Home

Kohler M20 User's Manual

1. Figure 9 5 Removing Air Cleaner Base REMOVE INTAKE MANIFOLD AND CARBURETOR A WARNING Explosive Fuel Gasoline may be present in the intake manifold car buretor and fuel system Gasoline is extremely flammable and its vapors can explode if ignited Keep cigarettes sparks open flames and other sources of ignition away from the engine Wipe up spilled fuel immediately SECTION 9 DISASSEMBLY 1 Note the position of govemor spring in govemor arm and speed control lever Loosen the hex nut and remove govemor arm and plain washer from cross shaft Refer to Figure 9 6 Governor Intake Prag Linkage Carburetor Manifold 7 YN 1 1 v x i y pee wy ME Speed Control Governor at MET Lever Spring q Figure 9 6 Removing Governor Arm Carburetor and Intake Manifold NOTE Loosening the hex nut or removing gover nor arm will disrupt govemor arm to cross shaft adjustment Readjustment will be Tequired upon reassembly 2 Remove the governor spring from govemor arm and speed control lever Remove the governor linkage from govemor arm and carburetor throttle lever 3 Loosen the hose clamp and remove fuel line from fuel pump outlet 4 Remove the hex cap screws split lock washers lifting straps intake manifold with carburetor and intake manifold gaskets Refer to Figure 9 7 Hex Cap Screws And Lock Washers Hex Cap Screws And Lock Washers BW Lifting Strap Carbu
2. Fan Flywheel Fan Fastener Torque in 10 Flywheel Fastener Torque ft Ib 4 Fuel Pump Mounting Screw Torque in Ib Ignition Ignition Module to Magnet Air Gap Spark Plug Type Champion or Equiv Spark Plug Gap ccs cece cece cee nennen nent Spark Plug Torque ft Ib Fill OIl Filter 52 173 01 Oil Fill Cap Torque 16 Engine Mtd Filter Adapter Fastener Torque in Ib Remote Oil Fitter Cover Fastener Torque in Ib Remote Oil Line Fitting Nut Torque in Ib Remote Oil Line Reducing Connector Torque in Ib Remote Oil Line Flare Nut Torque in Ib Remote Oil Filter Adapter Fitting Torque in Ib Oil Filter Installation Torque in Ib Oil Filter Bypass Cover Fastener Torque in Ib Ol Pump Pump Shaft to Crankcase Running Clearance Pump Drive Gear End 1 8 Model M18 3 1245 3 1255 3 128 002 0015 15 20 003 115 40 40 45 008 012 RV17YC 0 035 10 15 30 45 125 125 65 80 65 80 100 120 90 130 50 80 125 0010 0026 010 029 Model M20 3 1245 3 1255 3 128 002 0015 15 20 003 115 40 40 45 008 012 RV17YC 0 035 10 15 30 45 125 125 65 8
3. Iniet Duct Heater Cover Or Heater Plate v INCORRECT Figure 5 6 Installing Anti Icing Air Cleaner Cover 5 Install the wing nut Tighten wing nut 1 2 to 1 full turn after nut contacts cover Do not overtighten SERVICE Precleaner If so equipped wash and reoil the precleaner every 25 operating hours more often under extremely dusty or dirty conditions 1 Remove the precleaner from paper element Wash precleaner in warm water with detergent 2 Rinse the precleaner thoroughly until all traces of detergent are eliminated Squeeze out excess water do not wring Allow precleaner to air dry 3 Saturate the precleaner in clean fresh engine oil Squeeze out excess oil 4 Reinstall the precleaner over paper element Paper Element Every 100 operating hours more often under extreme ly dusty or dirty conditions check the paper element Replace the element as follows 1 Remove the precteaner if so equipped element Cover seal s elernent cover and paper element 2 Gently tap the flat side of the paper element to dislodge dirt Do not wash the paper element or use pressurized air as this will damage the ele ment Replace a dirty bent or damaged element with a new genuine Kohler element Handle new elements carefully do not use if surfaces are bent or damaged 3 Reinstall the precleaner cleaned and oiled over the paper element 4 Reinstall the paper element element cover and element cove
4. P Threaded Crankshaft Pump Application EP Generator Q Quiet Model MODEL 185 24501 SERIALNO 1523128516 REFER TO OWNERS MANUAL FOR OPERATION MAINTENANCE INSTRUCTIONS AND SAFETY PRECAUTIONS IK KOHLER COMPANY KOHLER WSCONSIN USA NOTE Engine model codes with a 3rd digit of 5 or greater denote MAGNUM engines Figure 1 2 Engine Identification Decals 13 SECTION 1 SAFETY AND GENERAL INFORMATION OIL RECOMMENDATIONS Using the proper type and weight of oil in the engine crankcase and in the gear reduction unit is extremely important as is checking oil daily and changing oil regularly Failure to use the correct oil or using dirty oil causes premature engine wear and failure Oil Type Use high quality detergent oil of API American Petroleum Institute Service Class SF or SG Select the viscosity based on the air temperature at the time of operation as shown in the table Recemmended SAE Viscosity Grades pru TNR gas 30 100 40 SW 20 5W NE 3 3 3 xi 331 iE um E BEFORE OL m Straight 30 weight oil is preferred SAE 10W 30 and 10W 40 are not recommended above 32 F 0 C Using these oils substantially increases oil consump tion and combustion chamber deposits NOTE Using other than Service Class SF or SG oil or extending oil change intervals longer than rec ommended could cause engine damage which is
5. Silicone Rubber RTV102 White RTV109 Gray GE Silicone Products RTV103 Black RTV154 Gray Distributors RTV106 Red RTV156 Red RTV108 Clear Silmate Black GE Silicone Instant Gasket Red Automotive Hardware and Discount Stores GE Silicone Hi Temp Instant Gasket Red Automotive Hardware and Discount Stores Loctite Superflex Silicone Adhesive 593 Black Loctite Distributors Sealant 594 White 595 Clear Permatex Silicone Form A Gasket 6 Blue 3 oz Bubble pack tube Automotive Hardware 6B Blue 3 oz Boxed tube and Discount Stores 6C Blue 11 oz Cartridge 6M Blue 12 oz Tube 66B Clear 3 oz Tube 66C Clear 11 oz Tube NOTE Using an outdated sealant can result in seal leakage All of the above sealants have a one to two year storage life 3 Lubricate the O Ring of camshaft bore plug with 4 Place the 2 crankcase side on the 1 side Ap engine oil Insert the plug into the camshaft bore ply thumb pressure on the plug as the sides are in flywheel end of 1 crankcase side brought together Maintain pressure on the plug as the crankcase fasteners are installed and tight When reinstalling a used plug make sure the ened This ensures the plug shoulder is bottomed marks scribed on the crankcase and plug during tightly against the crankcase Refer to disassembly are aligned Refer to Figure 11 19 Figure 11 20 Align Scribed gt Marks Figure 11 19 Installing Camshaft Bore Plug Figure 11 20 Installing 2 Crankcase
6. 1 125 M18 1 390 M20 Valve Guide Depth See Figure 10 5A for 30 Figure 10 5 Valve Detalls 45 Angle 30 CHANGEOVER See Figure 10 5A Beginning with Serial No 1917809296 a new cam shaft and 30 exhaust valve and seat went into pro duction for all Magnum twin cylinder engines and Short Blocks Cylinder barrels are now serviced as 1 and 2 side The same barrel does not work for both sides as it had previously The new camshaft is marked with a circle 3 8 diame ter of orange dye for easy part identification The new camshaft is available as a kit Part No 82 755 13 10 4 This kit includes a camshaft and four tappets The tappets included in the kit require a setling of 003 006 intake 013 016 exhaust When replacing the camshaft on engines prior to Seri 8l No 1917809296 also order and install valve kit 82 755 11 for M18 or 82 755 12 for M20 The valve kit includes a 30 exhaust valve and valve seat Re move the old seat install new seat and grind the seat to the 30 angle The new 30 exhaust valve has clearance specification of 013 016 SECTION 10 INSPECTION AND RECONDITIONING Under Valve Seat Insert oo Cut 1 380 i 031 Min Margin 1 125 M18 Face 1 390 M20 Valve Guide Depth Normal Even after long hours of operation a valve can be recon Bad Condition The valve depicted here should be replaced ditio
7. 2 Change the oil and filter while the engine is still warm from operation See Change Oil and Oil Filter 3 The fuel system must be completely emptied or the gasoline must be treated with a stabilizer to prevent deterioration 1f you choose to use a sta bilizer follow the manufacturers recommenda tions and add the correct amount for the capacity of the fuel system Fill the fuel tank with clean fresh gasoline Run the engine for 2 3 minutes to get stabilized fuel into the carburetor To empty the system drain the fuel tank and car buretor or run the engine until the tank and system are empty Remove the spark plugs Add one tablespoon of engine oil into each spark plug hole Install plugs but do not connect the plug leads Crank the en gine two or three revolutions Store the engine in a clean dry place 3 8 M18 amp M20 SECTION 4 TROUBLESHOOTING When troubles occur be sure to check the simple 1 Hydrostatic transmission is not in neutral PTO causes which at first may seem too obvious to be drive is engaged considered For example a starting problem could be 2 Battery is discharged caused by an empty fuel tank 3 Safety interlock switch is engaged 4 Loose or faulty wires or connections Some common causes of engine troubles are listed 5 Faulty key switch or ignition switch 6 7 TROUBLESHOOTING GUIDE Englne Will Not Crank below use this as a guide to locate causi
8. NOTE Do not crank the engine continuously for more than 10 seconds at a time If the engine does not start allow a 60 second cool down period between starting attempts Failure to follow these guidelines can bum out the starter motor SECTION 8 ELECTRICAL SYSTEM AND COMPONENTS NOTE If the engine develops sufficient speed to dis engage the starter but does not keep running a false start the engine rotation must be allowed to come to a complete stop before attempting to restart the engine If the starter is engaged while the flywheel is rotating the starter pinion and flywheel ring gear may clash This can damage the starter NOTE If the starter does not crank the engine shut Off the starter immediately Do not make fur ther attempts to start the engine until the con dition is corrected Do not jump start using another battery Using batteries larger than those recommended can bum out the starter motor NOTE Do not drop the starter or strike the starter frame Doing so can damage the ceramic permanent magnets Troubleshooting Guide Starter Drive Service Every 500 operating hours or annually whichever comes first clean and lubricate the drive splines of the starter If the drive pinion is badly wom or has chipped or broken teeth it must be replaced It is not necessary to disassemble the starter to ser vice the drive components Refer to Figure 8 17 and Service drive
9. 3 Remove the breather hose base screw air clean er base air intake tube and gasket Air Cleaner NS 1 i Cover Seal gt A Element Cover Paper Element Base Screw Air Cleaner fase Breather Hose gt i Gasket Pa i T Air Intake s Tube QS ed Intake Elbow Wing A e Air Cleaner o a Cover P iS Optional S 7 Precleaner Flgure 5 2 Square Air Cleaner Assembly 5 1 SECTION 5 AIR CLEANER Reassembly 1 Install the gasket air cleaner base air intake tube Wing Nut breather hose and base screw P NOTE Make sure breather hose seals tightly in Air Cleaner air cleaner base and breather cover to Cover Prevent unfiltered air from entering engine The air cleaner cover seal must be in Element i stalled to base to prevent vibration Ex 2 cess vibration can cause stud holes in Element Cover cover to enlarge which will allow dirt to enter the engine Optional Precleaner 2 Install the paper element precleaner cleaned and oiled element cover and element cover seals 3 Install the air cleaner cover and wing nuts Tight Pacer Elinant en wing nuts 1 2 to 1 full tum after nuts contact cover Do not overtighten DOME Refer To Figure 5 3 Base Screws 4 Disassembly Air Cleaner 1 Remove the wing nut and air cleaner cover Base Ty TEE Breather 2 Remove the element cover seal element cover S paper element and prec
10. 10355 Timing Gauge when assembling engine L3 2 SCRAPER Used to scrape machined surfaces without 11762 damage apes HANDLE Used with bearing installers slide hammer and 3 4747 Handle valve seat installers mee TOOL BOARD AND HOOK SET Used to store and identify tools SEE FRONT PAGE 1 23 SECTION 2 SPECIAL TOOLS 24 TOOL USAGE CHART KIT NO 3211 VALVE TOOLS PART NO amp NAME M18 11726 Valve Seat Puller 11915 Forcing Screw 11918 Adapter 11811 Valve Seat Installer 3222 Slide Hammer 3268 Valve Guide Removal Kit 11763 Valve Guide Driver depth 11770 Valve Guide Depth Gauge 11771 Valve Guide Depth Gauge 11843 Valve Guide Reamer 5 16 BEARING AND SEAL INSTALLERS 11782Installer Seal Pro e 11783 Installer Seal Flywheel 11795 Handle Installer Seal 12020 Seal Sleeve USE AS REQUIRED 12126 Seal Sleeve USE AS REQUIRED 12127 Seal Sleeve USE AS REQUIRED 12128 Seal Sleeve USE AS REQUIRED MISCELLANEOUS TOOLS 10357 Flywheel Strap Wrench 1 2 11797 Offset Wrench 1 2 11762 Scraper 4747 Drive Handle 3226 Flywheel Puller Kit N HR SECTION 2 SPECIAL TOOLS ENGINE ANALYSIS KIT NO KO 1000 Digital Tachometer Digital Engine Analyzer Thermocouples Digital Voltmeter Digital Thermometer Slack Tube Manometer
11. 3125 Intake Valve Guide Max Wear Limit 005 005 Exhaust Valve Guide I D Max Wear 007 007 1 9 SECTION 1 SAFETY AND GENERAL INFORMATION NOTES 1 Use standard torque values when specific values are not given Standard values have a tolerance of or 20 2 All dimensions are in inches unless otherwise specified 3 Also applies to self tapping screws 4 Lubricate with oil at assembly 5 3 8 16 thread with hex head nut and fiber gasket 2 Torque in increments to the value specified Do not overtorque do not loosen and retorque hex nuts on Posi Lock connecting rods 7 Refer to the Reassembly Section for instructions and tightening sequence STANDARD TORQUE VALUES 8 Top and center compression rings 9 Measurements D1 on Style D pistons are made perpendicular to piston pin in the position shown v2 L Coll ae 01 n 10 Refer to the Lubrication System Section for addi tional information Bolts Screws Nuts and Fasteners Botts Screws Nuts and Fasteners Assembled Into Cast Iron or Steel Assembled Into Aluminum 26969 96 27 24 Size Grade 2 Grade5 Grade 8 Size Grade 2 Grade 5 Grade 8 8 32 20 in 25 in Ib 8 32 20 in Ib 20 in Ib 20 in Ib 410 24 32 in 40 in Ib 10 24 32 in Ib 32 in Ib 32 in Ib 10 32 32 in 40 in Ib 1 4 20 70 in Ib 70
12. 4 Clogged or restricted fuel lines 1 Grass screen cooling fins or shrouding 5 Faulty choke or throttle controls cables clogged 6 Faulty spark plugs 2 Excessive engine load 7 Carburetor improperly adjusted 3 Low crankcase oil level 8 Incorrect valve to tappet clearance 4 High crankcase oil level 9 Low compression 5 Carburetor improperly adjusted 41 SECTION 4 TROUBLESHOOTING Engine Knocks 1 Low crankcase ail level 2 Excessive engine load 3 Old improper fuel 4 Internal wear or damage Engine Loses Power Low crankcase oil level High crankcase oil level Restricted air cleaner element Dirt or water in fuel system Excessive engine load Engine overheating Faulty spark plugs Carburetor Improperly adjusted Low compression Engine Uses Excessive Amount Of Oii 1 Incorrect oil viscosity type 2 Clogged or improperly assembled breather system 3 Worn or broken piston rings 4 Wom cylinder bores 5 Wom valve stems and or valve guides 6 Crankcase being overfilled EXTERNAL ENGINE INSPECTION Before cleaning or disassembling the engine check its external appearance and condition This inspection can give clues to what might be found inside the en gine and the cause once it is disassembled OOND AYN Check for buildup of dirt and debris on the crank case cooling fins grass screen and other exter nal surfaces Dirt or debris in these areas are cau
13. 609 Screw slotted bind head 6 Throttle Shaft Replacement Kits 25 757 14 25 757 15 25 757 16 and 25 757 17 To determine which kit to use measure the throttle shaft being replaced and select the shaft with corre sponding dimensions shown in the chart below Each kit contains Installation instructions and the following Qty beserteton Gasket bowl retaining screw Gasket bowl ring Gasket baffte Screw slotted head machine Shatt throttle Bushing throttle shaft Sealer Loctite amp No 609 Screw slotted bind head Spacer X 400 80 CHART THROTTLE SHAFT REPLACEMENT KIT SELECTION _ gt 1 Throttle Shaft I Dimensions KtNumbers A D 2575714 104 619 1 227 2 164 2575715 104 1 416 1 289 3 00 25 757 16 308 1 447 1227 3 00 25757 17 322 1 073 1 227 2 68 SECTION 6 FUEL SYSTEMS AND GOVERNORS To Replace Throttle and Choke Shafts A WARNING Prevent Eye Injury Suitable eye protection safety glasses goggles or face hood should be worn for any procedure involv ing the use of compressed punches hammers chisels drills or grinding tools Disassemble Carburetor Refer to Disassembly Steps 1 3 Remove Choke Plate and Choke Shaft Transfer Choke Lever To ensure correct reassembly mark choke plate and carburetor body with a mark
14. Carrying Case Figure 2 2 Engine Analysis Kit No KO 1000 The Kohler Engine Analysis Kit contains a selection of instruments which will enable you to measure critical items that relate to engine performance You will find many uses for these instruments from basic crank Case vacuum checks to sophisticated application tests The kit includes the following Qty Description Part No 1 Digital Voltmeter KO 1001 1 Digital Tachometer KO 1002 1 Digitat Thermometer KO 1004 1 Digital Engine Analyzer KO 1003 1 Slack Tube Manometer KO 1005 1 8 ft Lead With Plug KO 1006 3 14 mm Spark Piug Thermocouple KO 1007 2 Head Bolt Thermocouple KO 1008 1 Sump Thermocouple KO 1009 1 1 4 x 1 8 Bushing KO 1010 B 1 3 8 x 1 8 Bushing KO 1010 A 1 1 2 x 1 8 Bushing KO 1010 C 1 3 4 x 1 8 Bushing KO 1010 D 1 Tube With Fittings KO 1011 B 1 Carrying Case KO 1013 3 Piain Thermocouple KO 1015 The voltmeter tachometer thermometer and engine analyzer feature state of the art electronic circuitry and digital readouts Guidelines for using the instruments and testing are included Using the instruments in the kit you will be able to m Measure temperatures of spark plug base gasket cylinder head bolt oil sump air into flywheel and carburetor Measure engine speed RPM Measure crankcase vacuum and exhaust system back pressure m Measure voltage Measure charging system current Measure elec
15. Testing Module Primary flywheel magnet as possible tighten the hex flange screws slightly 2 Insert a 014 flat feeler gauge or shim stock be tween the magnet and module Refer to Figure 8 5 Figure 8 4 Testing Module Secondary Figure 8 6 Setting Magnet to Module Air Gap 8 3 SECTION 8 ELECTRICAL SYSTEM AND COMPONENTS 3 Loosen the hex flange screw so the magnet pulls module against feeler gauge Tighten the hex flange screw securely 4 Remove the feeler gauge or shim stock Due to the pull of the magnet the bracket and hardware will flex slightly The magnet to module air gap should be within the range of 008 012 5 Rotate the flywheel back and forth check to make sure the magnet does not strike the module Check gap with feeler gauge and readjust if necessary 6 Install the kill lead to kill terminal of module Rein stall the blower housing Kill Lead With Optional Diode An optional in line diode was installed in the kill lead of some early Magnum engines to protect the module from buming out if voltage was applied to the kill lead Refer to Figure 8 7 The diode was later added 10 the internal circuitry of the module so they would all have the same protection Heat Shrink Tubing Diode f To Kill Switch Coated Terminal Or OFF Position Fiberglass Of Keyswitch Sleeving Figure 8 7 Kill Lead With In Line Dio
16. breather hose and gasket Reassembly 1 Install the gasket air cleaner base breather hose and base screws NOTE Make sure breather hose seals tightly in the air cleaner base and breather cover to prevent unfiltered air from entering engine 2 Install the air cleaner base seal paper element precleaner cleaned and oiled element cover and element cover seal 3 Install the air cleaner cover with the inlet duct po sitioned for the season of operation Refer to the decai on the air cleaner cover Figure 5 5 Position Air Cleaner As Shown Below For Proper Engine Operation ENGINE TOP VIEW WINTER SUMMER BELOW 45 F 10 C ABOVE 45 F 10 C Figure 5 5 Typical Decal Anti Icing Air Cleaner Cover Positions For Winter Position Make sure the inlet duct fits completely over heater plate or heater cover Refer to Figure 5 6 Make sure the air cleaner cover is sealed tightly around the entire perimeter of air cleaner base NOTE Proper sealing around base is necessary to prevent unfiltered air from entering the engine To prevent vapor lock and to ensure proper engine operation do not operate the engine during summer season with the air cleaner cover in the winter position Always refer to the decal on the air cleaner cover for proper position 5 3 SECTION 5 AIR CLEANER Cleaner Cover Heater Cover Or Heater Platen CORRECT PA Air Cleaner Cover
17. later use bracket as shown in Figure 6A 19 Operation Centrifugal force acting on the rotating govemor gear assembly causes the flyweights to move outward as speed increases and inward as speed decreases As the flyweights move outward they force the regulating pin of the assembly to move outward The regulating pin contacts the tab on the cross shaft causing the shaft to rotate with changing speed One end of the cross shaft protrudes through the top of the crank case Through extemal linkage attached to the cross shaft the rotating action is transmitted to the throttle plate of carburetor When the engine is at rest and the throttle is in the fast position the tension of the governor spring holds the throttle valve open When the engine Is op erating governor gear assembly is rotating the force applied by the regulating pin against the cross shaft tends to close the throttle valve The governor spring tension and the force applied by the regulating pin are in equilibrium during operation holding the engine speed constant Wnen a load is applied and the engine speed and governor speed decreases the governor spring ten sion moves the govemor arm to open the throtlle plate wider This admits more fuel and restores engine speed This action takes place very rapidly so a re duction in speed is hardly noticed As the speed reaches the govemed setting the governor spring ten sion and the force applied by the regulat
18. 2 Figure 10 6 Pulling Valve Guide Install 5 16 18 NC nut on coarse threaded end of 2 1 2 long stud 2 Insert other end of stud through valve guide bore and install 5 16 24 NF nut Tighten both nuts securely NOTE Valve guide must be held firmly by the stud assembly so that all slide hammer force will act on the guide 3 Assemble the valve guide removal adapter to the stud and then the slide hammer to the adapter 4 Use the slide hammer to pull the guide out Install Valve Guide To install valve guide proceed as follows 1 Make sure valve guide bore is clean and free of nicks or bums 2 Using valve guide driver Refer to Section 2 Special Tools align and then press guide in until valve guide driver bottoms on depth gauge See Figure 10 7 Driver Tool 11763 Depth Gauge Tool 11770 tor M18 A 11771 for M20 Cylinder Barrel Figure 10 7 Installing Valve Guide 3 Valve guides are often slightly cornpressed during insertion Use a piloted reamer Refer to Section 2 Special Tools and then a finishing reamer to resize the guide bore to 3125 Refer to Figure 10 8 10 7 SECTION 10 INSPECTION AND RECONDITIONING 5 16 Reamer Figure 10 8 Reaming Valve Guide Valve Seat Inserts Intake valve seats are usually machined into the cylin der barrel however certain applications may specify hard alloy inserts The exhaust valve seats are re placea
19. Apply finger pressure to the throttle lever shaft to keep it firmly seated against pivot in carburetor body Rotate the throttle shaft until the throttle plate fully closes the bore around its entire perim eter then tighten screws Refer to Figure 6B 10 Throttle Lever Tightening ud Shaft Assembly Apply Pressure When Figure 6B 10 Installing Throttle Lever Shaft 4 Operate the throttle lever check for binding be tween the throttle plate and carburetor bore Loosen screws and adjust throttle plate as neces sary then torque screws to 8 12 in 1b 6B 8 Choke Shaft Installation 1 Install the detent spring and ball into the carbure tor body NOTE If the detent ball does not drop through the tapped air cleaner base screw hole by its own weight do not force it Forcing the ball could permanently lodge it in the hole Install the ball through the choke shaft bore instead 2 Compress the detent ball and spring Insert the choke lever shaft assembly into carburetor body with the cutout portion of shaft facing the air clean er mounting surface refer to Figure 6B 11 Make sure the choke lever is on the correct side of car buretor body Compress Bail And Spring Cutout Portion Ot Choke Shaft Figure 68 11 installing Choke Lever Shaft 3 Install the choke plate to choke shaft Make sure the plate is positioned properly in bore as marked and noted during disassembly The numbers stamped
20. D 4 Ma Lead C s f c QU E ONU EC KIII Switch Kill Terminal B OFF Position Of Keyswitch Laminations A Assembly Ignition Module Figure 8 1 Magnum Electronic Magneto Ignition System 8 1 SECTION 8 ELECTRICAL SYSTEM AND COMPONENTS ignition System Troubleshooting Guide The following guide will help locate and comect ignition system related starting problems This procedure uses a simple tester which can be easily made by the serviceman Refer to the Special Tools Section for ignition sys tem tester construction details NOTE Use a low voltage ohmmeter when ohmmeter is required Always zero ohmmeter on each scale before testing to ensure accurate readings Problem Test Conclusion 1 Make sure spark plug leads are connected to spark plugs 2 Check condition of spark plugs Make sure If plugs ara in good condition check adjust Qaps are set to 035 gaps and reinstall 3 Check ignition module using test plugs refer to If visible and audible sparks ARE produced the the Special Tools section and Figure 8 2 ignition module is OK Remove the high tension leads from the It visible and audible sparks ARE NOT engine spark plugs and connect them to produced the test plugs amp Make sure engine ignition switch and or NOTE To maintain engine speeds normally key switch are in the run position obtained during cranking do not re m
21. Ib 2 Install the fuel inlet needle into inlet seat Install float and slide float pin through float hinge and float hinge towers on carburetor body 3 Set float levet Invert carburetor so the float tab rests on the fuel inlet needle There should be 11 64 or 1 32 clearance between the machined surface of body and the free end of float Bend the float tab with a small screwdriver to adjust Refer to Figure 6A 13 Bend Tab To Adjust Inverted Carburetor Figure 6A 13 Setting Float Level 4 Set float drop Tum the carburetor over to its nor mal operating position and aliow float to drop to its lowest level The float drop should be limited to 1 1 32 between the machined surface of body and the bottom of the free end of float Bend the float tab with a smaif screwdriver to ad just Refer to Figure 6A 14 Bend Tab To Adjust Figure 6 14 Setting Float Drop 5 Check float to float hinge tower clearance In vert the carburetor so the float tab rests on the fuel inlet needle Insert a 010 feeler gauge between float and float hinge towers If the feeler gauge cannot be inserted or there is interference be tween the float and towers file the towers to ob tain the proper clearance Refer to Figure 6A 15 0 010 Feeler Gauge Both Sides Float File If Necessary Float Hinge Towers On Carburetor Body Inverted Carburetor Figure 6A 15 Checking Float Cl
22. M18 1 1 4 TURNS 1 1 4 TURNS M20 1 1 4 TURNS 1 TURN 3 Start the engine and run at half throttle for five to ten minutes to warm up The engine must be warm before making final settings 4 Maln Fuel Needle Setting This adjustment is possible only on adjustable main jet carburetors if the carburetor is a fixed main jet type disregard this Place the throttle into the fast position Tum the adjusting needle In clockwise The en gine speed may increase then it will decrease as the needle is tumed in lean Note the position of the needle Back the needle out approximately 1 4tum See Figure 6B 4A for best main fuel performance Back out Appx 1 8 to 1 4 Lean turn Lean Figure 6B 4A Optimum Main Fuel Setting 5 Low Idle Speed Setting Piace the throttle con tro into the idle or slaw position Set the low idle speed to 1200 RPM or 75 RPM by tuming the low idle speed adjusting screw in or out Check the speed using a tachometer NOTE The actual low idle speed depends on the application Refer to the equipment man ufacturer s instructions for specific low idle speed settings To ensure best re sults when setting the low idle fuel needle the low idle speed must not ex ceed 1500 RPM 6 Low Idle Fue Needle Setting Place the throttle into the idle or slow position Tum the adjusting needle in clockwise The en gine speed may increase then it
23. Remove the main fuel jet 5 In order to clean the off idle ports and the bowl vent channel thoroughly the welch plugs covering these areas must be removed Use tool No KO1018 and the following procedure to re move the welch plugs Refer to Figure 6B 6 Pry Out Plug Do Not Allow Tip To Strike Carburetor Body Pierce Plug With Tip Welch Plug Figure 68 6 Removing Welch Plugs a Pierce the welch plug with the tip of the tool NOTE To prevent damage to the carburetor do not allow the tooi to strike the carburetor body b Pry out the welch plug using the tool Throttle and Choke Shaft Removal Further disassembly to remove the throttle shaft and choke shaft is recommended only if these parts are to be cleaned or replaced Throttle Shaft Removal 1 Because the edges of throttle plate are beveled mark the throttle plate and carburetor body with a marking pen to ensure correct reassembly refer to Figure 6B 7 Also take note of the throttle plate position in bore and the position of the throttle lever Marking Pen Figure 6B 7 Marking Throttle Plate and Carburetor Body 2 Carefully and slowly remove the screws securing the throttle plate to throttle shaft Remove the throttle plate 3 File off any burrs which may have been left on the throttle shaft when the screws were removed Do this before removing the throttle shaft from carbu retor body 4 Remove the throttle lever shaft assemb
24. Switch Testing Test the switch for continuity using an ohmmeter or continuity test light For each switch position continu ity should be present across the terminals listed in the table below Switch Continuity Position Across Terminals 1 OFF G M A 2 RUN B A R 3 START B S SOLENOID A solenoid is used on applications The solenoid is an electrically actuated normally open switch de signed for heavy current loads Refer to Figur 8 16 Stud Terminals Solenoid Case Ground Tab Terminal Figure 8 16 Starter Solenold The solenoid is used to switch the heavy current re quired by the starter using the key switch designed for low current loads Testing 1 Connect an ohmmeter or continuity tester across the stud terminals of solenoid 2 Apply 12 volts DC across the tab terminal and case ground of solenoid and observe ohmmeter or tester NOTE Apply positive of voltage supply to tab terminal negative to case ground 3 The ohmmeter or tester should indicate continuity as long as voltage is applied If there is no conti nuity the solenoid is probably faulty and should be replaced Check the solenoid further using an ohmmeter Step 4 8 12 SECTION 8 ELECTRICAL SYSTEM AND COMPONENTS 4 Measure the resistance of the coil in the solenoid using an ohmmeter Connect one meter lead to the case ground and one lead to the tab terminal If the re
25. White Tracer Remote Oil Line Flared Nuts 100 120 in Ib Reducing Connectors Oil Filter Snug 1 2 Turn 8 Remote Oil Filter Adapter Hex Nipple 90 130 in ib Reducing Connector 90 130 in Ib Female Swivel Couplings 65 80 in Ib Remote Line Red Tracer Figure 7 8 Installation Torques Remote Mounted OII Fitters CRANKSHAFT SPLINED INSERT LUBE INTERVAL RECOMMENDATION While it was previously thought that spline lubricant would remain effective for as long as the pump mount ing remained intact we now recommend that splines be re lubricated every 500 hours of operation Misalignment and lack of lubricant remain as the two major causes of premature wear and or costly tooth damage to splined inserts Without any recom mended interval spline service was being neglected resulting in damage 7 3 SECTION 7 LUBRICATION SYSTEM Every 500 hours of operation separate the pump from the engine Clean the splined areas and lightly grease the male portion of pump spline Use either Dow Coming G N Metal Assembly Paste or 77 As sembly Paste As you remount the pump to the engine be certain the mating surfaces are clean and free of any foreign ma terial and that the pump is correctly aligned If you have a splined insert that has been damaged the following kits are available for spline replacement Descriptio Kohler Part No 9 tooth insert 82 755 02 11 toot
26. adjusting needie main fuel jet and welch plugs Clean all passages and blow out with compressed air 4 Fuel leaks from carburetor 4a Float level set too high See Remedy 2c b Dirt under fue inlet needle See Remedy 2d C Bowl vent plugged Remove fuel bowl and clean bow vent Biow out with compressed air d Float is cracked or damaged Replace float Bowl retaining screw gasket damaged Replace gasket f Bowi retaining screw is not tightened Torque screw to 6B 3 SECTION 6B FUEL SYSTEMS ADJUSTING WALBRO CARBURETORS In general tuming the adjusting needles in clockwise decreases the supply of fuel to the carburetor This gives a fuel to air mixture Tuming the adjust ing needles out counterclockwise increases the sup Ply of fuel to the carburetor Main Fuel Needie Figure 68 3 Walbro Adjustable Main Jet Carburetor NOTE The tip of the low idle fuel and main fuel adjusting needles are tapered to critical dimensions Damage to the needles and the seats in carburetor body will result if the needles are forced 1 With the engine stopped tum the adjusting needle s In clockwise until it bottoms fightiy 2 Preliminary Settings Turn the adjusting needie s out counterclockwise from lightly bot tomed as follows or to the rich side of adjustment H WALBRO FIXED JET LOW IDLE M18 1 1 4 TURNS M20 1 1 4 TURNS WALBRO ADJ LOW IDLE MAIN FUEL
27. are equipped with a full flow oil fil ter The filter helps remove sludge and other combus tion by products from the oil extends the oil change interval and helps cool the oil Oil filters are optional for special spec engines and are available in engine mounted or remote mounted types A cover plate seals the crankcase on those engines not equipped with an oil filter Refer to Figures 7 5 7 6 7 7 and 7 8 Also refer to the Periodic Maintenance Section for oil and oil filter change instructions Pressure Ii Switch Closure Plate Figure 7 3 Pickup Figure 7 5 Engine Mounted Oil Fliter and Oil Sentry Pressure Switch 72 SECTION 7 LUBRICATION SYSTEM Oil Filter Adapter ro Q Gasket x J N Oil Filter Snug 1 2 Turn Socket Screws 125 Ib Bypass Cover amp be Hex Socket Cap Gasket Screws 125 in Ib Figure 7 6 Installation Torques Engine Mounted Oll Filter Figure 7 7 Installation Torque Filter Bypass Cover Engines Without Oil Filter Female Swivel 90 130 in Ib Couplings 65 80 in Ib Remote Oil Line White Tracer Male Rigid Couplings 65 80 in Ib Hex Socket Cap Screws 125 in Ib a v Red Tracer Remote Oil Filter ce E WC 65 80 in ib N Hex Socket Cap Screws 125 in Ib Reducing Connector E 2 Remote Oil Line
28. as follows 1 Hold the drive pinion in a vise with soft jaws when removing and installing the stop nut The arma ture wili rotate with the nut only until the drive pin ion stops against internal spacers NOTE Do not overtighten the vise as this can distort the drive pinion 2 Remove the dust cover stop nut stop gear spacer anti drift spring dust cover spacer and drive pinion 3 Clean the drive shaft splines with solvent Dry the splines thoroughly Problem Possible Fault Correction 1 Clean corroded connections and tighten loose connections Wiring 2 Replace wires in poor condition and with frayed or broken insulation STARTER Starter Switch Bypass the switch or solenoid with a jumper wire if starter cranks normally replace FAILS or the faulty parts TO ENERGIZE Solenoid Battery Check specific gravity of battery If tow recharge or replace battery as necessary Battery Check specific gravity of battery If low recharge or replace battery as necessary Brushes Check for excessively dirty or worn brushes and commutator Clean using a coarse cloth not emery paper Replace brushes if excessively or unevenly worn STARTER Make sure the clutch or transmission is disengaged or placed in neutral This is ENERGIZES especially important on equipment with hydrostatic drive The transmission must BUT TURNS Transmission be exactly in neutral to prevent resistance which could keep the engine from SLOWLY or starting Engine Check for seize
29. burns avoid contact with skin eyes and clothing Batteries produce explosive hydrogen gas while being charged To prevent a fire or explosion charge batteries only in well ventilated areas Keep sparks open flames and other sources of ignition away from the battery at all times Keep batteries out of the reach of children Remove all jewelry when servicing batteries Before disconnecting the negative ground cable make sure all switches are OFF If ON a spark will occur at the ground cable terminal which could cause an explosion if hydrogen gas or gasoline vapors are present SECTION 1 SAFETY AND GENERAL INFORMATION ENGINE IDENTIFICATION NUMBERS When ordering parts or in any communication involv ing an engine always give the model specification and serial numbers of the engine Decal The engine identification numbers appear on a decai or decals affixed to the engine shrouding Refer to Figure 1 1 The significance of these numbers is shown below Identification E Figure 1 1 Location of Engine Identification Decal MODEL NO M 18 Magnum Engine Version Code Horsepower S Electric Start G Tapered Crankshaft Generator Application B SPEC NO 24501 Engine Model Code T variation Of Code Model Basic Engine 245 M18 495 M20 C SERIAL NO 1523128516 Year Manufactured Factory Code 15 1985 16 1986 17 1987 18 1988 19 1989 20 1990 21 1991 22 1992 23 1993 24 1994 25 1995
30. by the en gine Also disconnect other electrical acces sories in common ground with the engine 3 Prevent the stator AC leads from touching or shorting while engine is running This could permanently damage the stator 8 6 SECTION 8 ELECTRICAL SYSTEM AND COMPONENTS Electric Start Engines 15 amp Regulated Charging System Spark Plugs Ground To Kill Lead White Violet Ignition 5 Blue Module AP J Soe cee fili Fl gt Flywheel BEEN Keyswitch Stator 1 o Edo 4 1 c 1 H 1 Optional of J Tt Fuse f Rectifier z Pind Regulator bz il Sentry s ptional Seiten T Amen Indicator Light Optional Oil Sentry Switch Shutdown Starter Figure 8 9 Wiring Diagram Electric Start Engines 15 amp Regulated Battery Charging System E AC Leads Rectifier Regulator 15 Amp Stator Figure 8 10 15 amp Stator and Rectifier Regulator 8 7 SECTION 8 ELECTRICAL SYSTEM AND COMPONENTS Electric Start Engines 25 amp Regulated Charging System Spark Plugs Ground To Kill Lead White Ai 557 5 Blue Bw B AC Flywheel Stator GND Keyswitch AC Optional Q Rectifier Regulator Optional Oil Sentry i Switch Optional A Oil Sentry Indicator Light A
31. change in load if a big drop in speed occurs when normal load is applied the govemor should be set for greater sensitivity The standard spring position is in the fifth hole from cross shaft in governor arm and in the sixth hole from hex cap screw in speed control lever The po Sitions can vary depending on the engine application Therefore make a note of or mark the spring posi tions before removing it from the governor arm and speed control lever Refer to Figure 6A 20 Increase Sensitivity M Speed Control Lever Figure 6A 20 Governor Sensitivity Adjustment 6A 14 To increase sensitivity increase the govemor spring tension by moving the spring in govemor arm towards the cross shaft To decrease sensitivity and allow broader control decrease spring tension by moving the spring in gov emor arm away from the cross shaft ENGINE MOUNTED THROTTLE AND CHOKE CONTROLS Some M18 and M20 engines are equipped with throttle and choke controls mounted to the intake man ifold Refer to Figure 6A 21 DISASSEMBLY 1 Remove the intake manifold carburetor from engine 2 Remove the truss head nylock screw spring washer locking tab friction washers and throttle control lever Disconnect throttle linkage from speed contro lever on intake elbow 3 Remove the self tapping screw and throttle stop plate from Intake manifold 4 Remove the hex cap screw speed control lever high speed stop
32. frequency stated in the table Required Maintenance Check Oil Level Clean Grass Screen Check Replace Fuel Filter Change Oil and Filter Clean Foam Precleaner Clean Cooling Fins and Extemal Surfaces Clean Paper Air Cleaner Element Check Spark Plugs Check Valve To Tappet Clearance Clean Cylinder Heads and Combustion Chambers Service Starter Motor Drive Frequency Daily Daily As Required As Specifled in Oil Change Intervals Table 25 Hours 50 Hours 100 Hours 100 Hours 500 Hours 500 Hours Annually or 500 Hours Perform these maintenance procedures more frequently when engine is operated under extremely dusty and dirty conditions 250 Hours when leaded gasoline is used A WARNING Accidental Starts Before servicing the engine or equipment always remove the spark plug leads to prevent the engine from starting accidentally Ground the leads to pre vent sparks that could cause fires CHECK OIL LEVEL The importance of checking and maintaining the prop er oil level in crankcase cannot be overemphasized Check oil BEFORE EACH USE as follows 1 Make sure the engine is stopped level and is so the oil has had time to drain into the sump 2 Clean the area around dipstick before removing to keep dirt grass clippings etc out of the engine 3 Remove dipstick and wipe oil off Reinsert dip Stick and push it al
33. fuel is reach ing the combustion chambers If there is no fuel at tips fo spark plugs check for fuel flow from the fuel tank Test 3 3 Check for fuel flow from the fuel tank to fuel pump A Remove the fuel line from inlet fitting of fuel pump B Hold the line below the bottom of tank Open the shut off valve if so equipped and observe flow 4 Check operation of fuel pump A Remove the fuel line from inlet fitting of carburetor B Crank the engine several times and observe flow FUEL FILTER Some engines are equipped with an in line fuel filter Visually inspect the filter periodically Replace when dirty with a genuine Kohler filter Refer to Figure 6A 2 Fuel Filter Figure 6A 2 In Line Fuel Fitter 3 If fuel does flow from line check for faulty fuel pump Test 4 If fuel does not flow from line check for clogged fuel tank vent shut off valve screen and fuel lines If fuel does not flow from line check for clogged fuel line If line is unobstructed fuel pump is faulty and must be replaced If fuel does flow from fuel line the carburetor is probably faulty Refer to the Carburetor portion of this section FUEL PUMP Most Magnum engines are equipped with a mechani cally operated fuel pump On applications using a gravity feed fuel system the fuel pump is not used and the pump mounting pad on the crankcase is covered The fuel pump body is cons
34. in blown cylinder head gaskets If gasket fails in area surrounding one of the retaining capscrews high temperature gases can bum away portions of the aluminum alloy head A cylinder head in this condition must be replaced It will also be nec essary to replace the head screws The high tempera tures that caused the blown gasket could have made the screws ductile which will cause them to stretch when tightened If the cylinder heads appear in good condition use a block of wood or plastic scraper to scrape away car bon deposits Be careful not to nick or scratch the aluminum especially in gasket seating area Cylinder heads should also be checked for flatness Use a feeler gauge and a surface plate or piece of plate glass to make this check Cylinder head flat ness should not vary more than 003 if it does re place the cylinder head see Figure 10 1 NOTE Measure cylinder head flatness between each cap screw hole Apply Slight Downward Pressure Figure 10 1 Checking Cylinder Head Flatness SECTION 10 INSPECTION AND RECONDITIONING CYLINDER BARRELS Inspection and Reconditioning Check all gasket surfaces to make sure they are free of gasket fragments Gasket surfaces must also be free of deep scratches or nicks Scoring of the Cylinder Wall Unbumed fuel in severe cases can cause scuffing and scoring of the cylinder wall As raw fuel seeps down the cylinder wall it washes the
35. necessary lubricating oils off the piston and cylinder wall so that the piston rings make metal to metal contact with the wall Scoring of the cylinder wall can also be caused by localized hot spots result ing from blocked cooling fins or from inadequate or contaminated lubrication If the cylinder bore is badly scored excessively wom tapered or out of round resizing is necessary Use an inside micrometer to determine amount of wear refer to Specifications Tolerances and Special Torque Values Section 1 then select the nearest suitable oversize of either 003 010 020 or 030 Resizing to one of these oversizes will allow usage of the available oversize piston and ring assemblies Initially resize using a boring bar then use the follow ing procedures for honing the cylinder Honing While most commercially available cylinder hones can be used with either portable drills or drill presses the use of a low speed drill press is preferred as it facili tates more accurate alignment of the bore in relation to the crankshaft crossbore Honing is best accom plished at a drill speed of about 250 RPM and 60 strokes per minute After installing coarse stones In hone proceed as follows 1 Lower hone into bore and after centering adjust so that the stones are in contact with the cylinder wall Use of a commercial cutting cooling agent is recommended 2 With the lower edge of each stone positioned even with the lowest edge of t
36. operating the engine at high altitudes the main fuel mixture tends to get over rich An over rich mix ture can cause conditions such as black sooty ex haust smoke misfiring loss of speed and power poor fuel economy and poor or slow response To compensate for this a special high altitude main fuel jet is available for each carburetor The high alti tude main fuel jet is sold in a kit which includes the jet and necessary gaskets 6B 10 SECTION 6B FUEL SYSTEMS The following table lists the kits and the altitudes above which the kits should be used Engine Model Kit No Altitude M18 52 755 74 6000 1 M20 52 755 68 6000 ft High Altitude Jet Installation 1 Remove the fuel bowl retaining screw retaining screw gasket fuel bowl and bowl gasket NOTE If necessary remove the air cleaner and carburetor from engine to make fuel bowl removal easier 2 Remove the float pin float and fuel inlet needle 3 Remove the existing main fuel jet 4 Install the new high altitude main fuel Jet and torque to 12 16 In Ib 5 Reinstall the fuel inlet needle float and float pin 6 Install the new bowl gasket from kit and the fuel bowl Make sure the bowl gasket and bow are centered and positioned properly to ensure a good seal 7 Install the new bowl retaining screw gasket form kit and the bowl retaining screw Torque screw to 45 55 In Ib 8 Reinstall the carburetor and air cle
37. warrn it up 2 Remove spark plug s and air filter from engine 3 Rotate crankshaft until piston of cylinder being tested is at top dead center of compression stroke You will need to hold the engine in this position while testing The holding tool supplied with the tester can be used if the PTO end of the crankshaft is accessible Slide the holding tool onto the crankshaft and adjust the set screw to fit in the key slot Instalt a 3 8 breaker bar into the square hole of the holding tool so it is perpendic ular to both the holding tool and crankshaft PTO if the flywheel end is more accessible you can use a breaker bar and socket on the flywheel nut screw to hold it in position You may need an as sistant to hold the breaker bar during testing If the engine is mounted in a piece of equipment you may be able to hold it by clamping or wedg ing a driven component Just be certain that the engine cannot rotate off of T D C in either direction 4 Install the adapter into the spark plug hole but do not attach it to the tester at this time 5 Connect an adequate air source to the tester m Turn the regulator knob in the increase clockwise direction until the gauge needle is in the yellow set area at the low end of the gauge 7 Connect tester quick disconnect to the adapter Note the gauge reading and listen for escaping air at the carburetor intake exhaust outlet and crank case breather 8 Check your test
38. will decrease as the needle is turned in lean Note ttie position of the needle Back the needle out approximately 1 8 to 1 4 tum See Figure 6B 4B for best low idle fuel performance 6B 4 SECTION 6B FUEL SYSTEMS Adjust TE To Midpoint m Figure 6B 4B Optimum Low 10 Fuel Setting Throttle Lever Shaft Assembly Throttle Shaft Throttle Plate Dust Seal TES Throttle Plate Retaining Screws Carburetor Body Idle Fuel Adjusting 4 7 And Sprin Choke Detent E 2 S Bail And Spring amp lt 7 y Idle Speed Adjusting Choke Plate s wo Screw And Spring o SS S Choke Plate e US 25287 Welch Plugs Retaining Screws Fixed Main Shaft Assembly CARNE t Fuel Jet Fuel Iniet Needle Fuel Bowl Gasket Float cds E Fue Bowl Fuel Bowl Retaining Screw And Gasket Figure 6B 5 Walbro Built Carburetor Exploded View 6B 5 SECTION 6B FUEL SYSTEMS Disassembly Refer to Figures 6B 2 and 68 5 1 Remove the bowi retaining screw retaining screw gasket and fuel bowl 2 Remove the bowl gasket float pin float and fuel inlet needle NOTE To prevent damage to the carburetor do not attempt to remove the fuel inlet seat as itis not serviceable Replace the car buretor if the fuel inlet seat is damaged 3 Remove the idle fuel adjusting needle and spring Remove the idle speed adjusting screw and spring 4
39. will require more frequent service Gasollne Alcohol blends Gasohol up to 1096 ethyl alcohol 9096 unleaded gasoline by volume is approved as a fuel for Kohler engines Other gasoline alcohol blends are not approved Gasoline Ether blends Methyl Tertiary Butyl Ether MTBE and unleaded gaso line blends up to maximum of 15 MTBE by volume are approved as a fuel for Kohler engines Other gasoline ether blends are not approved F die _uncentenrocenten n Tides OUTLETS ou rarer j diee j A Ane so ner nn d ron Wi santy one gie ow E Q PE L3 BU CENTER or Gray re Figure 1 3 Overall Dimensions Model M18 and M20 1 5 SECTION 1 SAFETY AND GENERAL INFORMATION SPECIFICATIONS TOLERANCES AND SPECIAL TORQUE VALUES DESCRIPTION Model Model General Specifications M18 M20 Horsepower 3 600 18 20 Displacement cu in 42 18 46 98 Lj wlio AE E 3 12 3 12 oly dole TUS eig crit 2 75 3 06 Compression Ratio 6 0 1 6 6 1 Approx 0 0 130 130 Approx Oi Capacity U S Quarts 1 5 1 5 For best results fill to F mark on dipstick as opposed to adding a given quantity of
40. 0 65 80 100 120 90 130 50 80 125 0010 0026 010 029 SECTION 1 SAFETY AND GENERAL INFORMATION Model Model M18 M20 Piston and Piston Rings E Style D Pistons Thrust Face O D Dt 3 1203 3 1210 3 1208 3 1215 Thrust Face O D 01 Max Wear Limit 3 1181 3 1186 Thrust Face to Bore Clearance D1 New 0035 0052 0030 0047 Piston Ring End Gap 010 023 010 023 Piston Ring End Gap Used Max 032 032 Piston Ring Side Clearance 006 006 Piston Pin O D New 8247 6249 7499 7501 Valves and Tappets Intake Valve to Tappet Clearance Cold 003 006 003 006 Exhaust Valve to Tappet Clearance Cold Serial No 1816500646 and earlier 016 019 016 019 Serial No 1816500656 and later 011 014 011 014 Intake Valve Minimum Lift Zero Lash 274 274 Exhaust Valve Minimum Litt Zero 1 274 274 Intake Valve Minimum Stem 3103 3103 Exhaust Valve Minimum Stem OD 3088 3088 Nominal Seat Angle Serial No 1816500646 and earlier 45 45 Serial No 1816500656 and later 30 30 Valve Guide 5126 3125
41. 1 Remove the hex flange screws and ignition mod ule Refer to Figure 9 15 Hex Flange Screws Figure 9 15 Removing gnitlon Module 2 Remove the hex flange screws and bracket from 1 cylinder barrel Refer to Figure 9 16 1 Cylinder Barrel Figure 9 16 Removing ignition Module Bracket REMOVE GRASS SCREEN FLYWHEEL AND FAN NOTE Always use the flywheel strap wrench to hold the flywheel when loosening or tightening fly whee and fan retaining fasteners Do not use any type of bar or wedge between fins of cooling fan as the fins could become cracked or damaged Always use a puller to remove flywheel from crankshaft Do not strike the crankshaft or flywheel as these parts could become cracked or damaged Refer to Section 2 Special Toots for recom mended tools 9 5 SECTION 9 DISASSEMBLY 1 Remove the grass screen from fan Refer to Figure 9 16 2 Hold the flywheel with the strap wrench and loos en the hex cap screw Remove hex cap screw split lock washer and plain washer Refer to Figure 9 17 Figure 9 17 Removing Flywheel Fastener 3 Remove the flywheel fram crankshaft using a pull er Refer ta Figure 9 18 Strap Wrench Figure 9 18 Removing Flywheel Using A Puller 4 Remove the hex flange screws spacers and fan Refer to Figure 9 19 Spacers 4 Hex Flange Screws 4 Figure 9 19 Removing Fan From Flywheel A W
42. 10 16 K Engines Connecting Rod 800 Magnum Engines Connecting Rod Figure 10 16 Posl Lock Connecting Rods NOTE KT17 Series II engines built after Serial No 15089862 are equipped with the new style D pistons piston rings and connecting rods Inspection and Service Check bearing area big end for excessive wear Score marks running and side clearances Refer to Section 1 Specifications Tolerances and Special Torque Values Replace rod and cap if scored or excessively wom Service replacement connecting rods are available in STD crankpin size and 010 undersize The 010 undersized rod can be identified by the drilled hole located in the lower end of the rod shank refer to Figure 10 17 Always refer to the appropriate parts information to ensure that correct replacements are used Standard 010 Undersize Figure 10 17 Standard and 010 Undersize Service Connecting Rods CAMSHAFT AND CRANKSHAFT Inspection and Service Inspect the gear teeth on both the crankshaft and camshaft If the teeth are badly wom chipped or some are missing replacement of the damaged com ponents will be necessary Also inspect the crankshaft bearings for scoring grooving etc Do not replace bearings unless they show signs of damage or are out of running clearance specifications If crankshaft tums easily and noise lessly and there is no evidence of scoring grooving etc on the race
43. 20 SECTION 10 INSPECTION AND RECONDITIONING Clean all parts thoroughly Only clean parts can be accurately inspected and gauged for wear or damage There are many commercially available cleaners that quickly remove grease oil and grime accumulation from engine parts When such a cleaner is used fo low the manufacturers instructions and safety precau tions carefully Use gasket remover or paint remover to remove RTV from crankcase and closure plate Do not scrape the surfaces when cleaning as this will damage the surfaces This could result in leaks Make sure that all of the cleaner is removed before the engine is reassembled and placed in operation Even small amounts of these cleaners quickly break down the lubricating properties of engine oil Refer to A Guide to Engine Rebuilding TP 2150 for additional information Measurement Guide TP 2158 A and Engine Inspection Data Record TP 2435 are also available use these to record in spection results FLYWHEEL Inspection Inspect the flywheel for cracks and the flywheel keyway for damage Replace flywheel if cracked Replace the flywheel the crankshaft and the key if flywheel key is sheared or the keyway damaged Inspect ring gear for cracks or damage Kohler no longer provides ring gears as a serviceable part Re Place flywheel if the ring gear is damaged CYLINDER HEADS Inspection Blocked cooling fins often cause localized hot spots which can result
44. 3 Identify other engine components such as the valves pistons connecting rods and rod caps and valve tappets prior to removal or disassembly REMOVE SPARK PLUGS AND CYLINDER HEADS 1 Remove the spark plugs from cylinder heads 2 Remove the hex cap screws plain washers cyl inder heads and gaskets Refer to Figure 9 22 SECTION 9 DISASSEMBLY Spark Plug Cylinder Head Figure 9 22 Removing Spark Plugs and Cylinder Heads REMOVE CYLINDER BARRELS 1 Remove the hex nuts and plain washers using the barrel wrench Refer to Figure 9 23 Cylinder Barrel MI Hex Nuts And Plain Washers 6 Figure 9 23 Removing Cylinder Barrel Fasteners 2 Using a soft faced hammer carefully tap the cyl inder barrels between the intake and exhaust ports to break the seal between cylinder barrels and crankcase 3 Support the weight of barrels with hands and carefully pull the barrels from the studs and pis tons Refer to Figure 9 24 NOTE To prevent damage to pistons or connect ing rods when removing barrels make sure the cylinder barrels and connecting rods are supported at all times Do not allow the pistons or connecting rods to drop against edges of crankcase 9 7 SECTION 9 DISASSEMBLY Support Barrels And Pistons When Removing Figure 8 24 Removing Cylinder Barrels 4 Thoroughly remove the sealant from the mating Surfaces of crankcase and cylinder barrels NOTE The us
45. ARNING Ignition Magnet Is Not Removable or Serviceable Do not attempt to remove the ignition magnet from flywheel Loosening or removing the magnet mounting screws could cause the magnet to come loose and be thrown trom the engine causing se vere injury Replace the flywheel if magnet is damaged REMOVE ELECTRIC STARTER 1 Remove the hex nuts split lock washers wiring hamess clamp wiring hamess and electric start er Refer to Figure 9 20 oe R 252 Nuts And Lock Washers jp Figure 9 20 Removing Electric Starter and Stator REMOVE STATOR 1 Remove the self tapping screws and stator Refer to Figure 9 20 9 6 IDENTIFY ENGINE SIDES To ensure proper reassembly it is necessary to identi fy the engine sides and various other engine compo nents Refer to Figure 9 21 The 1 side of engine has the cylinder barrel closest to the flywheel end of crankshaft The 2 side of engine has the cylinder barrel closest to the PTO end of crankshaft Cylinder Head Crankcase Halves D Cylinder Barrel Figure 9 21 Identifying Engine Sides NOTE To prevent damage to the engine crank case and other components do not mark using a metal stamp 1 With a marking pen paint or chalk mark the crankcase halves and cylinder heads as 41 side and 2 side 2 The cylinder barrels are already identified as 1 or 2 by a mark stamped near the valve cover breather gasket surface
46. Always check level on dipstick before adding more oil On engines equipped with oil filter an additional 1 2 U S pint of oil is re quired when oil filter is replaced Angle of Operation Maximum At Full Oil Level Intermittent Operation Carb Side Up 1Cyl Up 35 1 Cyl Up 35 Carb Side Down 1 Cyl Down 35 1 Cyl Down 35 Flywheel End Up 30 30 Flywheel End Down 30 30 Camshaft End Play 003 013 003 013 Camshaft to Camshaft Bearing Running Clearance 0010 0025 0010 0025 Carburetor Prelirninary Main Fuel Screw Setting 4 aa a aE 2 1 2 2 1 2 Pretiminary Idle Fuel Screw Setting 1 1 11 64 or 1 32 11 64 or 1 32 Float Drop 1 1 32 1 1 32 Fuel Inlet Seat Torque in Ib 35 35 Bowl Retaining Screw Torque in Ib 50 50 Float to Float Pin Tower Clearance cH 010 010 16 SECTION 1 SAFETY AND GENERAL INFORMATION Connecting Rod Posl Lock New Service Rod Nut Torque Ib 46 Used Rod Nut Torque 16 46 Rod to Crankpin Running Clearance New Rod to Crankpin Max Wear Limit Rod to Piston Pin Running Clearance New Rod to Side Play on Crankpin Crankcase Cylinder Barrel Intake and Exhaust Manifold Fastener Torque in Ib Closure Plate Fa
47. CE AIR CLEANER Magnum engines are equipped with a high density paper air cleaner element Some specifications are also equipped with an oiled foarn precleaner which surrounds the paper element Refer to Figure 3 4 SECTION 3 PERIODIC MAINTENANCE Also refer to the Air Cleaner Section for disassembly and reassembly procedures for all styles of air clean ers used on these engines Re Base Element Element Cover Cover Seals Optional Paper Element Precleaner Figure 3 4 Air Cleaner Components Precleaner If so equipped wash and reoil the precleaner every 25 operating hours more often under extremely dusty dirty conditions 1 Remove precleaner from paper element Wash the precleaner in warm water with detergent 2 Rinse precleaner thoroughly until all traces of de tergent are eliminated Squeeze out excess water do not wring Allow precleaner to air dry 3 Saturate precleaner in clean fresh engine oil Squeeze out excess oil 4 Reinstall precleaner over paper element Paper Element Every 100 operating hours more often under extreme ly dusty or dirty conditions check the paper element Replace the element as follows 1 Remove the precleaner if so equipped element Cover seals elernent cover and paper element 2 Replace a dirty bent or damaged element with a new genuine Kohler element Handle new ele ments carefully do not use if surfaces are bent or damaged 3 3 SECT
48. ION 3 PERIODIC MAINTENANCE NOTE Do not wash the paper element or use pressurized alr as this will damage element 3 Install the precleaner cleaned and oiled over pa per element 4 Reinstall the paper element element cover and element cover seals 5 Install air cleaner cover and wing nuts Tighten wing nuts 1 2 to 1 full turn after nuts contact cov er do not overtighten Inspect Air Cleaner Components Whenever the air cleaner cover is removed or the ele ment or precleaner serviced check the following components Air Cleaner Base Make sure it seals tightly against intake elbow and is not bent or damaged Element Cover and Element Cover Seals Make Sure element cover is not bent or damaged Make sure element cover seals are in place to ensure element is sealed tightly between element cover and air cleaner base Breather Tube Make sure it is sealed tightly in air cleaner base and breather cover NOTE Damaged worn or loose air cleaner compo nents could allow unfiltered air into the engine causing premature wear and failure Replace damaged or worn components CLEAN AIR INTAKE COOLING AREAS To ensure proper cooling make sure the grass screen cooling fins and other external surfaces of engine are kept clean at all times Refer to Figure 3 5 Every 50 operating hours more often under extremely dusty dirty conditions remove the blower housing and other cooling shrouds Clean the
49. N AND RECONDITIONING Figure 10 3 Measuring Cylinder Bore Clean Cylinder Bore After Honing Proper cleaning of the cylinder walls following boring and or honing is very critical to a successful overhaul Machining grit left in the cylinder bore can destroy an engine in less than one hour of operation after a rebuild The final cleaning operation should always be a thor ough scrubbing with a brush and hot soapy water Use a strong detergent that is capable of breaking down the machining oil while maintaining a good level of suds If the suds break down during cleaning dis card the dirty water and start again with more hot wa ter and detergent Following the scrubbing rinse the Cylinder with very hot clear water dry it completely and apply a light coating of engine oil to prevent rusting Measuring Piston to Bore Clearance Before installing the piston into the cylinder bore it is necessary that the clearance be accurately checked This step is often overlooked and if the clearances are not within specifications generally engine failure will result NOTE Do not use a feeler gauge to measure piston to bore clearance it will yield inaccurate measurements Use a micrometer The following procedures should be used to accurate ly measure the piston to bore clearance 1 Use a micrometer and measure the diameter of the piston 1 2 above bottom of piston skirt per pendicular to the pi
50. REASSEMBLY INSTALL VALVE COVER AND BREATHER On 1 Side 1 Install the gasket breather plate seal and filter Refer to Figure 11 41 Breather Cover Figure 11 41 Installing Breather Components 2 Install the gasket breather cover copper washer and hex nut Refer to Figure 11 42 NOTE Hole in cover should be directly over mesh filter Hex Nut And Copper Washer La Figure 11 42 Installing Breather And Valve Cover On 2 Side 1 Instali the gasket valve cover copper washer and hex nut Refer to Figure 11 42 INSTALL BLOWER HOUSING CYLINDER HEAD BAFFLES AND TOP BAFFLE 1 Route the stator leads and wiring harness to top of crankcase between crankcase and fuel pump 2 install the high tension leads and kill lead into grommet Install the grommet in slot in blower housing 3 Install the blower housing and self tapping screws 4 Install the 1 side cylinder head baffle and self tapping screws 5 Install the 2 side cylinder head baffle and self tapping screws 6 Install the top baffle and self tapping screws INSTALL SOLENOID KEY SWITCH RECTIFIER REGULATOR AND CONNECT WIRING 1 Install the spacer solenoid with bracket and self tapping screws Connect the leads to starter sole noid Secure wiring harness to solenoid with a new wire tie Refer to Figure 11 43 Self Tapping Self Tapping Screw And Spacer Figure 11 43 Installing Starter So
51. RELIEF VALVE AND REAR OIL SEAL 1 Remove the hex flange screws closure plate and gasket Refer to Figure 9 28 3 Hex Socket Hex Flange Screws 9 Figure 9 30 Removing Oil Filter Adapter SPLIT THE CRANKCASE 1 Scribe a line across the camshaft bore plug and the 1 crankcase side This line Is used to align the plug on reassembly Refer to Figure 9 31 Closure Plate Figure 9 28 Removing Closure Plate 2 Remove the oil pressure relief valve spring steel ball and sleeve Refer to Figure 9 29 Figure 9 31 Camshaft Bore Plug 2 Put tape or govemor spring around the tappet stems in the 42 crankcase side This prevents the Figure 9 29 Removing Oil Pressure Relief Valve tappets from falling into the 1 side when the crankcase is split 3 Remove the hex nuts plain washers and hex 3 Remove the rear oil seal from closure plate REMOVE OIL FILTER ADAPTER flange screws securing the crankcase halves 1 Remove the hex socket head screws oil filter together adapter and gasket Refer to Figure 9 30 4 Lay the crankcase down so the 2 side is up Locate the splitting notches in the seam of the crankcase Pry the halves apart using the blade of a large screwdriver Refer to Figure 9 32 9 9 SECTION 9 DISASSEMBLY Figure 9 32 Splitting The Crankcase NOTE Insert the screwdriver only in the splitting notches Do not pry on the gasket surfaces o
52. RETOR REPAIRS Always use new gaskets when repairing and reinstall ing a carburetor The following covers the kits avail able for reconditioning the Kohler built 1 venturi size gasoline fuel carburetors used on the M18 amp M20 en gines Three repair kits one Choke and one Throttle Shaft Replacement Kits are now available Refer to Figure 6A 7 for components described in the following Carburetor Repair Kits No 25 757 01 and No 25 757 02 Contains These kits include all gaskets and fuel inlet compo nents generally used in reconditioning a Kohler built 1 carburetor Kit No 25 757 01 is for basic carbure tors while 25 757 02 is used for carburetors with float dampening springs Qty Description Gasket bow retaining screw Gasket bowl ring Gasket baffle Gasket fuel inlet seat Needle and Seat fuel inlet Pin float hinge Float Repalr Kit No 25 757 03 Contalns Use this kit to replace damaged or leaking floats on all Kohler built 1 carburetors Description Float Assembly Gasket battle Choke Shaft Replacement Kit No 25 757 21 This kit is used to replace wom or damaged choke shaft assemblies Each kit contains installation in structions and the following components Qty Description Gasket bowl retaining screw Gasket bowl ring Gasket baffle Spring choke shaft Ball choke shaft Screw slotted head machine Shaft choke Bushings choke shaft Sealer Loctite No
53. SECTION 6A FUEL SYSTEMS AND GOVERNORS Install Throttle Shaft Bushing 1 Make sure the dust seal counterbore in carburetor body is thoroughly clean and free of chips and burrs 2 Instail a throttle shaft without throttle lever into carburetor body to use as a pilot Use one of the remaining new throttle shafts from kit 3 Coat the outside surface of throttle shaft bushing with Loctite from kit Slip bushing over shaft Using installation tool from kit and vise press bushing into counterbore until it bottoms in carbu retor body Refer to Figure 6A 11 Installation Tool Figure 6A 11 installing Throttle Shaft Bushings 4 Allow Loctite to set for 5 10 minutes then re move throttle shaft 5 install new throttie shaft with lever into carburetor body Rotate shaft and check for binding NOTE If binding occurs locate cause and cor rect before proceeding Use throttle shaft to align bushing if necessary 6 Remove shaft and allow Loctite to set for an additional 30 minutes befare proceeding 7 Wipe away all excess Loctite from bushing and throttle shaft Install Detent Spring and Ball Choke Shaft and Choke Plate 1 Install new detent spring and bail into carburetor body in the side opposite choke lever 2 Compress detent ball and spring and insert choke shaft through bushings Make sure the choke le ver is on the correct side of carburetor body Re fer to Figure 6A 12 Com
54. Screw Solenoid g Screw And Spacer Figure 9 11 Removing Starter Solenold REMOVE TOP BAFFLE CYLINDER HEAD BAFFLES AND BLOWER HOUSING 1 Remove the self tapping screws and top baffle 2 Remove the self tapping screws and 1 side cyl inder head baffle 3 Remove the self tapping screws and 2 side cyl inder head 4 Remove the self tapping screws and blower housing REMOVE BREATHER AND VALVE COVER On 1 Side 1 Remove the hex nut copper washer breather cover and gasket Refer to Figure 9 12 Hex Nut And Copper Washer Breather Cover Hex Nut And Valve Cover Copper Washer Figure 9 12 Removing Breather and Valve Cover 2 Remove the filter seal breather plate and gasket Refer to Figure 9 13 SECTION 9 DISASSEMBLY Figure 8 13 Removing Breather Components On 2 Side 1 Remove the hex nut copper washer valve cover and gasket Refer to Figure 9 12 REMOVE FUEL PUMP A WARNING Explosive Fuel Gasoline may be present in the fuel pump Gasoline is extremely flammable and its vapors can explode if ignited Keep cigarettes sparks open flames and other sources of ignition away from engine Wipe up fuel Immediately 1 Remove the truss head screws fuel pump and gasket Refer to Figure 9 14 Fuel Pump Truss Head 7 Screw Deo am Figure 9 14 Removing Fuel Pump REMOVE IGNITION MODULE AND BRACKET
55. Seal Installer 11783 Seal Installer 11784 Seal Installer 11785 Seal Installer 11788 Seal Installer 11787 Seal Installer 11790 Seal Installer 11791 Seal Installer 11792 Seal Installer 11793 Seal Installer 11795 Handie Used to install seals without damage and to prop er depth Use 11795 handle with installers 2 2 SECTION 2 SPECIAL TOOLS SEAL AND BEARING INSTALLERS TOOL NO amp NAME APPLICATION ILLUSTRATION 12020 75 12021 1 00 12022 125 12126 1 12 12127 1 50 12128 1 44 3242 SEAL PROTECTOR SLEEVE KIT Used on crankshaft when installing seals to pre vent damage 3241 BEARING INSTALLING KIT 12014 Ins Crank Bushing 12015 Ins Cam Bushing 12016 12017 12018 amp 12109 Brg Installers Used to install amp remove engine bearings and bushings OTHER APPLICATIONS 3226 FLYWHEEL PULLER KIT 12485 Puller w forcing screw 5108 Bolt 1 4 w washer 3 12505 Bolt 10 24 w washer 2 12504 Bolt 3 8 w washer 2 12506 Storage Bag FLYWHEEL STRAP WRENCH 10357 OFFSET WRENCH 11797 Wrench 1 2 4923 Wrench 9 16 Used to remove flywheels and bearing plates from engine Used to hold flywheel for nut removal Used to remove amp install cylinder barrel retaining nuts FEELER GAUGE Used to set oil pump drive gear backlash on twin 12033 11767 cylinder engine TIMING GAUGE Used to hold balance gears in timed position
56. Side SECTION 11 REASSEMBLY Install the hex flange screws plain washers and hex nuts 6 Torque fasteners 1 through 6 in the sequence shown to a preliminary vatue of 100 In Ib Torque the remaining fasteners to 100 In Ib in the most expedient sequence Refer to Figure 11 21 Figure 11 21 Crankcase Fastener Torque Sequence 7 Torque fasteners 1 through 4 to 260 In ib Torque fasteners 5 and 6 to 200 In Ib Torque the remaining fasteners to 200 In Ib in the most expedient sequence Refer to Figure 11 21 8 Locate a center punch in the previous stake marks surrounding the camshaft bore plug Restake the plug securely in place Refer to Figure 11 22 Center Punch Figure 11 22 Restaking Camshaft Bore Plug 9 Remove the tape or govemor spring from tappets in 2 crankcase side INSTALL FRONT OIL SEAL 1 Slide the appropriate seal sleeve refer to Section 2 Special Tools over flywheel end of crankshaft Generously lubricate lips of front oil seal with light grease Slide oil seal over sleeve Refer to Figure 11 23 Sleeve Figure 11 23 Installing Oil Seal Using Sleeve 2 Using the 11795 handle and appropriate seal driver install the front oil seal to a depth of 1 32 3 64 1 64 Refer to Figure 11 24 Handle Figure 11 24 Installing Seal Using Driver INSTALL OIL FILTER ADAPTER 1 Install the gasket filt
57. alves 3 Compress the springs using a valve spring com pressor and install keepers Refer to Figure 11 33 11 12 Figure 11 33 Installing Valves Side 2 Shown INSTALL CYLINDER HEADS AND SPARK PLUGS 1 Install gaskets cylinder heads plain washers and hex cap screws lubricate threads with oil Torque hex cap screws in increments in the se quence shown in Figure 11 34 to 15 20 ft Ib Figure 11 34 Cylinder Head Fastener Torque Sequence 2 Install the spark plugs 0 035 gap torque to 10 15 ft Ib SECTION 11 REASSEMBLY INSTALL STATOR 1 Install the stator and self tapping screws Refer to Figure 11 35 Wiring Harness M Hex Nuts And Lock Washers Figure 11 35 Installing Stator and Electric Starter INSTALL ELECTRIC STARTER 1 Install the starter wiring hamess clamp split lock washers and hex nuts Refer to Figure 11 35 2 Install the wiring hamess in clamp so that the end of lead which connects to solenoid is approxi mately 4 1 2 to 5 from the clamp Bend clamp securely around wiring hamess INSTALL FAN FLYWHEEL AND GRASS SCREEN A WARNING Damaging Crankshaft and Flywheel Could Cause Personal Injury Using im proper procedures to install the flywheel can crack or damage the crankshaft and or flywheel This not only causes extensive engine damage but also is a Serious threat to the safety of person nearby since broken fragments could be thrown from
58. and prepared as directed by the sealant manufacturer Refer to INSTALL CAMSHAFT BORE PLUG AND SEAL SECTION 11 REASSEMBLY CRANKCASE earlier in this section for more infor mation on sealants Closure Plate Figure 11 26 Installing Pressure Rellef Valve 3 Apply a 1 16 bead of sealant to the closure plate as shown in Figure 11 27 Follow the sealant manufacturer s recommendations regarding setting Closure Plate Torque Sequence Sealant Figure 11 27 Closure Plate Sealant Pattern Closure Plate Fastener Torque Sequence 4 Install the closure plate and hex flange screws Torque screws to 150 in Ib in the sequence shown in Figure 11 27 5 Slide the appropriate seal sleeve over PTO end of crankshaft Generously lubricate the lips of rear oil seal with light grease Slide the oil seal over sleeve Refer to Figure 11 23 6 Using the 411795 handle and appropriate seal driver install the rear oil seal to a depth of 5 32 3 64 1 64 Refer to Figure 11 24 SECTION 11 REASSEMBLY CLOSURE PLATE ALIGNMENT Engines with Serial No 1830500016 and higher have two alignment pins pressed into the crankcase see Figure 11 26 to provide proper alignment of the clo sure plate On direct connected applications having splined crankshafts the correct alignment is essential to pre vent rapid spline wear due to excessive run out When rebuilding splined crankshaft engines t
59. aner to engine as necessary using the new gaskets from kit M20 Linkage and Dampening Spring Installation M20 engines built between Serial No 1619504216 and 1631600816 inclusive were built with a dampening spring connected to the govemor arm and the bushing in carburetor throttle lever The dampening spring can be eliminated by installing a new governor linkage and new bushings as shown in Figure 6B 15 These parts are available in Kit No 52 755 64 To reinstall the existing dampening spring bushings and govemor linkage use the following procedure 1 Install the bushings and govemor linkage as shown in Figure 6B 15 2 Install the dampening spring to govemor arm and bushing on carburetor throttle lever as shown in Figure 68 16 Make sure the end of spring with larger hook is installed around the bushing In car buretor throttle lever Governor Arm y 99 2 Linkage e PO Bushing Bushing Throttle Lever On Carburetor Figure 6B 15 Installing Bushings And Governor Linkage M20 Engines 68 11 SECTION 6B FUEL SYSTEMS Governor Arm Bushing Governor Linkage Throttle Lever On Carburetor Dampening Spring Bushing Bushing Governor Linkage Governor Arm Figure 6B 16 Installing Dampening Spring M20 Engines 6B 12 M18 amp M20 SECTION 7 LUBRICATION SYSTEM OPERATION oil pump maintains high oil flow and oil pressure even Magnum M18 an
60. ar limits and free of score or scuff marks the old piston may be Magnum M18 and M20 service replacement pistons are available in STD bore size and in 003 010 020 and 030 oversizes Replacement pistons in clude new piston ring sets and new piston pins reused Service replacement piston ring sets are also avail 2 Remove old rings and clean up grooves Never able separately for STD 003 same ring set for both reuse old rings sizes 010 1020 030 oversized pistons Al 3 Before Installing new rings on piston place top ways use new piston rings when installing pistons two rings each in tum in its running area in cylin Naver reuse old rings der bore and check end gap see Figure 10 13 The cylinder bore must be deglazed before service This gap should be 010 032 in a used cylinder ring sets are used bore and 010 023 in a new cylinder bore 10 11 SECTION 10 INSPECTION AND RECONDITIONING Figure 10 13 Measuring Piston Ring End Cap 4 After installing the new compression top and middle rings on piston check piston to ring side Clearance Maximum recommended side clear ance is 006 If side clearance is greater than 006 a new piston must be used Refer to Figure 10 14 Figure 10 14 Measuring Piston Ring Side Clearance Install Piston Rings To install piston rings proceed as follows NOTE Rings must be installed correctly Ring instal lation inst
61. ar to Shaft 4 Measure pump drive gear end play with a flat feel er gauge Refer to Figure 11 3 Recommend end play is 010 029 Add one 1 additional shim spacer if necessary to bring end play within range 6 Install the cover side marked OUT away from crankcase and self tapping screws Refer to Figure 11 5 Figure 11 5 Installing Oil Pump Cover Oil Pickup 1 Install the oil pickup tube Make sure tube is angled upward Install clamp and self tapping screw Refer to Figure 11 6 oil rms Figure 11 3 Measuring Oi Pump Drive Gear End Play 5 Lubricate the oil pump cavity with engine In stall inner and outer rotors Refer to Figure 11 4 Figure 11 4 Installing Oil Pump Rotors 11 2 Figure 11 6 Installing Pickup Components 2 Install the oil pickup housing and spring clip in stall narrow side of clip into crankcase first INSTALL CROSS SHAFT AND GOVERNOR SHAFT 1 install the plain washer cross shaft plain washer and retaining ring Refer to Figure 11 7 SECTION 11 REASSEMBLY Governor Arm Installed Later LT Plain Washer Installed Later Plain Washer Retaining Ring Cross Shaft Figure 11 7 Installing Governor Cross Shaft 2 install the thrust washer and govemor gear to stub shaft Refer to Figure 11 8 Cross Shaft Governor Gear Figure 11 8 Installing Governor Gear 3 Instail the copper was
62. ble alloy inserts If the seats become badly pitted cracked or distorted the inserts must be re placed The Inserts are a tight press fit in the cylinder barrel A valve seat removal tool is recommended for this job Refer to Section 2 Special Tools Since insert re moval causes loss of metal in the insert bore area use only Kohler service replacement inserts which are slightly larger to provide retention in the cylinder bar fel Make sure new inserts are properly started and pressed into bore to prevent cocking of the insert Remove Valve Seat Insert To remove a valve seat insert refer to Figure 10 9 and proceed as follows Forcing Screw 3 16 Hex Valve Seat Wrench 9 16 Open end or Box Wrench Barrel a Adapter Valve Seat Insert Puller Hex Nut Washer Figure 10 9 Pulling Valve Seat Insert Install valve seat puller on forcing screw and light ly secure with washer and nut Center the puller assembly on valve seat insert Hold forcing screw with a hex wrench to prevent tuming and slowly tighten nut See Figure 10 9a Continue to tighten nut until puller is tight against valve seat insert 10 8 SECTION 10 INSPECTION AND RECONDITIONING 5 Assemble adapter to valve seat puller forcing screw and slide hammer to adapter See Figure 10 9b 6 Use slide hammer to remove valve seat insert Install Valve Seat Insert To install valve sea
63. certain that oil pressure 20 psi or more is pres ent Run the engine for 5 10 minutes between idle and midrange Adjust the carburetor mixture settings as necessary 2 Make sure the maximum engine speed does not exceed 3750 RPM no load Adjust the throttle and choke contrals and the high speed stop as necessary Refer to the Fuel System and Gover nor Section 11 19 THE NEW SHAPE OF KOHLER POWER KOHLER 317355 ENGINE DIVISION KOHLER CO KOHLER WISCONSIN 53044 FOR SALES AND SERVICE INFORMATION IN U S AND CANADA CALL 1 800 544 2444 FORM NO TP 2204 B ISSUED 3 86 REVISED 5 93 MAILED 5 93 LITHO IN U S A
64. choke shaft bores then tighten vise This ensures the carburetor body and drill are perpendicular and in correct alignment Refer to Figure 6A 9 Figure 8A 8 Allgning Dritling Carburetor Body 3 Install a 19 64 dia drill a chuck Set drill press speed to a low speed suitable for aluminum Feed drill slowly to obtain a good finish to holes 4 Ream the choke shaft bores to a final size of 5 16 For best results use a piloted 5 16 reamer 5 Blow out all metal chips using compressed air Thoroughly clean the carburetor body in a carbu retor cleaner install Choke Shaft Bearings 1 install screws into the tapped holes that enter the choke shaft bores until the screws bottom lightly Refer to Figure 6A 10 N Figure 6A 10 Installing Choke Shaft Bushings Coat the outside surface of choke shaft bushings with Loctite from kit Carefully press bushings into carburetor body using a smooth jawed vise Stop pressing when bushings bottom against screws Allow Loctite to set for 5 10 minutes then re move screws Install new choke shaft in bushings Rotate shaft and check for binding NOTE If binding occurs locate and correct cause before proceeding Use choke shaft to align bushings if necessary Remove choke shaft and allow Loctite to set for an additional 30 minutes before proceeding Wipe away all excess Loctite from bushings and choke shaft 6A 9
65. cooting fins and extemal surfaces as necessary Make sure the cool ing shrouds are reinstalled Refer to the Disassembly and Reassembly Sec tions for cooling shroud removal and installation procedures NOTE Operating the engine with a blocked grass screen dirty or plugged cooling fins and or cooling shrouds removed will cause engine damage due to overheating KEEP THESE AREAS CLEAN Air Cleaner Air Intake Tube Blower Housing Grass Screen Crankcase Cooling Fins Cylinder Head Cooling Fins Batfles And Shrouds Figure 3 5 Air Intake and Coollng Areas 3 4 SECTION 3 PERIODIC MAINTENANCE CHECK SPARK PLUGS Every 100 operating hours remove the spark plugs check condition and reset gaps or replace with new plugs as necessary Refer to Figure 3 6 Wire Gauge Spark Plug 0 035 Gap l au Ground Electrode Figure 3 6 Servicing Spark Plugs Before removing spark plugs clean the area around the base of plugs to keep dirt and debris out of engine 2 Remove the plugs and check conditions Replace the plugs if wom or if reuse is questionable Use Champion Type RV17YC or equivalent spark plugs NOTE Do not clean the spark plugs in a machine using abrasive grit Some grit could re main in spark plugs and enter the engine causing extensive wear and damage 3 Check gaps using a wire feeler gauge Adjust gaps to 0 035 by carefully bend
66. correct settings can cause a fouled spark plug overheating excessive valve wear and other problems To ensure correct settings make sure the following adjustment procedures are used Make carburetor adjustments after the engine has warmed 6A 3 SECTION 6A FUEL SYSTEMS AND GOVERNORS Condition 1 Black sooty exhaust smoke engine sluggish 2 Engine misses and backfires at high speed 3 Engine starts and then stops under cold weather conditions 4 Engine runs roughly or stalls at idle speed tinue adjust the carburetor immediately if black exhaust smoke is noted check the air cleaner first An apparent over rich mixture can actually be caused by a clogged air cleaner element If after element is replaced black smoke or other problems con Possible Cause Probable Solution 1 Main fuel mixture too rich Tum main fuel adjusting needie in clockwise 2 Main fuel mixture tdo lean Tum main fuel adjusting needle out counterclockwise 3 Main fuel mixture too lean Turn main fuel adjusting needie out counterclockwise 4 Idle speed too low or improper idle fuel mixture Tum idle speed adjusting screw then idle fuel ad justing needle 1 Stop the engine Turn the main fuel and idle fuel adjusting needles in clockwise until they bottom lightly NOTE The ends of the main fuel and idle fuel ad justing needles are tapered to critical di mensions Damage to needles and seats will resul
67. d M20 engines use a full pressure at low speeds and high operating temperatures A lubrication system that delivers oil to the crankshaft pressure relief valve iocated in the engine crankcase camshaft and connecting rod journal surfaces Under behind the closure plate limits the maximum oil pres normal engine operating conditions the oil pressure sure in the system No adjustments to relief valve are can be as high as 50 psi A high efficiency Gerotor possible Refer to Figure 7 1 Camshaft Connecting Rod Journal Surfaces Bearing Surfaces Camshaft Full Flow Crankshaft Crankshaft Oil Filter Bearings Oil Level Oil Pump Pressure Relief Oil Level Valve Oil Pickup Figure 7 1 Full Pressure Lubrication System LUBRICATION SYSTEM SERVICE The crankcase must be split to service the pump il pi The oil pump cover and rotors and pressure relief shan drive gear oil pickup etc valve can be serviced without splitting the crankcase Refer to Figures 7 2 7 3 and 7 4 Also refer to the Remove the rear closure plate to service those parts Disassembly and Reassembly Sections for oil pump component removal and installation procedures 74 SECTION 7 LUBRICATION SYSTEM Outer Rotor Figure 7 2 Oll Pump Assembly Crankcase Figure 7 4 Pressure Rellef Valve OIL FILTER All basic engines
68. d engine components such as the bearings connecting rod and piston 4 Apply a small amount of Kohler electric starter drive lubricant Part No 52 357 01 to splines NOTE Kohler starter drive lubricant Part No 52 357 01 must be used on all Kohler electric starter drives The use of other lubricants can cause the drive to stick or bind 5 Apply a small amount of Loctite amp No 271 to stop nut threads 6 Reinstall the drive pinion dust cover spacer anti drift spring stop gear spacer and stop nut Torque stop nut to 160 In Ib Instalt the dust cover Disassembly 1 Remove the dust cover stop nut stop gear spacer anti drift spring dust cover spacer and drive pinion Refer to Starter Drive Service 2 Remove the thru bolts 3 Remove the drive end cap and thrust washer 8 14 SECTION 8 ELECTRICAL SYSTEM AND COMPONENTS 4 Remove the commutator end cap with brushes and springs 5 Remove the armature from inside the starter frame Brush Replacement Reter to Figure 8 18 Selt Tapping 7 Brush Springs Screw Negative Brush Brush Holder Negative Brush Self Tapping Screw Stud Terminal With Positive Brushes Figure 8 18 Commutator End Cap With Brushes Remove the brush springs from the pockets in brush holder 2 Remove the self tapping screws negative brushes and plastic brush holder 3 Remove the hex nut split lock washer pla
69. de The diode is rated such that diode failure is highly un likely If the diode should fail however two failure modes are possible If the diode fails in the shorted mode and voltage is applied to the kill lead the mod ule will bum out If the diode fails in the open mode the engine will continue to run when the kill switch is placed in the off position If either of these symp toms is experienced the diode should be tested 8 4 DIODE TEST Use an ohmmeter or continuity tester to test the diode Set the meter on Rx1 scale and zero 1 Disconnect the kill lead terminais from the kill switch and ignition module 2 Connect the meter tester leads to the kill lead ter minals Then reverse the leads In one direction the resistance should be infinity ohms no continuity With the leads reversed some resistance continuity should be measured 3 If the resistance is infinity ohms in both directions no continuity the kill lead or diode is open and the wiring hamess must be replaced Refer to the appropriate Parts Manual for the correct part number If the resistance In 0 ohms in both directions and the module is burned out replace the module only Spark Plugs Engine misfire or starting problems are often caused by spark plugs in poor condition or with improper gap setting SERVICE Every 100 operating hours remove the spark plugs check condition and reset gaps or replace with new plugs as necessary Refer to Fi
70. e The valve faces and seats must be lapped in before checking adjusting valve to tappet clearance 1 Rotate the crankshaft and look into the valve boxes The tappets will move in only one of the boxes 2 Install valves into valve guides for the cylinder in which no movement was observed Hold valves firmly against seat and measure valve to tappet Clearance with a flat feeler gauge Refer to Figure 11 32 11 11 SECTION 11 REASSEMBLY a Insert Flat Feeler Gauge Between Valve Stem And Tappet pose SN W Intake Valve Exhaust Valve Cylinder Barrel Valve Spring ARES Valve Springs Compressor Keepers Figure 11 32 Measuring Valve to Tappet Clearance Clearance Specifications Intake Valve Closest to Flywheel 003 006 Exhaust Valve Seat Angle Closest to PTO 45 016 019 30 011 014 Serlal No 1816500646 and later 3 Rotate the crankshaft 360 and measure the valve to tappet clearance for the remaining cylinder 4 If the clearance is insufficient grind the valve stems until the correct clearance is obtained Make sure the valve stems are ground perfectly flat and smoath If the clearance is excessive replace the valves and recheck clearance INSTALL VALVES 1 Install the intake valve seals to valve guides 2 Install the valve springs close coils towards cylin der head surface exhaust valve rotators lower intake valve spring retainers and v
71. e Air Bleed Air Cleaner Mounting Surface Idle Fuel Fuel Inlet Inlet Needle Figure 6B 2 Major Components and Service Locations Typical Walbro Carburetor 6B 2 SECTION 6B FUEL SYSTEMS Troubleshooting Make sure the carburetor is securely fastened to the engine using gaskets in good condition If engine troubles are experienced that appear to be fuel system related check the following areas before adjusting or disassembling the carburetor Make sure the fuel tank is filled with clean fresh gasoline Make sure the fuel tank cap vent is not blocked and that it is operating properly Make sure fuel is reaching the carburetor This includes checking the fuel shut off valve fuel tank filter screen in line fuel filter fuel lines and fuel e Make sure the air cleaner element is clean and all air cleaner components are fastened securely Make sure the ignition system governor system exhaust system and throttle and choke controls are operating properly If after checking the items listed above starting prob lems or other conditions similar to those listed in the following table exist it may be necessary to adjust or service the carburetor pump for restrictions or faulty components Condition Possible Cause Probable Remedy 1 Engine starts hard or runs roughly or 1 Idle fuel mixture or idle speed are improperly adjusted Adjust the idle q S
72. e of a gasket removing solvent is recommended Do not scrape the sur faces with a metal putty knife or similar tool Scratching the mating surfaces will cause leaks REMOVE VALVES 1 With a marking pen or paint mark the valves as coming from the 1 or 2 cylinder barrel Exhaust valves are already identified with an EX stamp on the valves 2 Compress the valve springs with a valve spring compressor and remove keepers Refer to Figure 9 25 3 Remove the valve spring compressor then re move valves lower intake valve spring retainers exhaust valve rotators and valve springs 4 Remove the intake valve seals from valve guides REMOVE PISTONS FROM CONNECTING RODS 1 With a marking pen or paint mark the pistons and connecting rods as 1 side and 2 side Refer to Figure 9 26 Connecting Rod Figure 9 26 Removing Pistons 2 Remove the piston pin retainers piston pins and pistons REMOVE PISTON RINGS 1 Remove the top and center compression rings using a ring expander tool Refer to Figure 9 27 Valve Spring Cylinder Barrel Compressor Intake Valve Stem Seal Exhaust Valve Rotator Valve Springs Keepers Top Compression Ring Ring Expander Too Figure 9 25 Removing Valves Figure 9 27 Removing Piston Rings 2 Remove the oil control ring rails then remove rails spacer SECTION 9 DISASSEMBLY REMOVE CLOSURE PLATE OIL PRESSURE
73. e ordered complete as shown Refer to Figure 2 1 or the tools can be ordered individually Contact your Kohler Dis tributor for price and availability w 2 Wes ea xl Figure 2 1 Special Service Tool Kit No 3211 24 SECTION 2 SPECIAL TOOLS VALVE SERVICE TOOLS TOOL NO amp NAME APPLICATION ILLUSTRATION VALVE SEAT PULLERS 11726 11913 Removal of valve seats use 11918 adapter 3222 slide hammer amp 11915 forcing screw FORCING SCREW 11915 Used with valve seat pullers 11726 amp 11913 ADAPTER 11918 Used to connect valve seat pullers to slide hammer VALVE SEAT INSTALLER Used to install intake and exhaust seats Use with 11838 Stud 3 1 2 12100 Stud 2 1 2 11800 Adapter 0917 Nut 12008 Nut 11811 4747 handle 11812 3222 SLIDE HAMMER Provides pulling force for valve seat and guide re 11799 Weight moval Use 4747 handle 12244 Slide Bolt 3268 VALVE GUIDE REMOVAL KIT Used to pull valve guides with 3222 slide hammer 12325 Driver 11763 Driver 11770 Gauge 11771 Gauge 3224 VALVE GUIDE INSTALLER KIT Used to install valve guides to proper depth Use 11763 driver with 11770 amp 11771 depth gauges REAMERS Valve Gulde 11843 5 16 11844 1 4 To ream valve guidos SEAL AND BEARING INSTALLERS 3223 SEAL INSTALLER KIT 11782
74. earance 6 Install the bowl gasket and baffle gasket Position baffle gasket so the inner edge is against the float hinge towers 7 Install the fuel bowl so it is centered on the baffle gasket Make sure the baffle gasket and bowl are positioned properly to ensure a good seal 8 Install the bowl retaining screw gasket and bowl retaining screw Torque screw to 50 60 In Ib 6 11 SECTION 6A FUEL SYSTEMS AND GOVERNORS 9 Install the idie speed adjusting screw and spring install the idle fuel and main fuel adjusting needles and springs Tum the adjusting needles clockwise until they bottom lightly NOTE The ends of adjusting needles are tapered to critical dimensions Damage to needles and seats will result if needles are forced 10 Reinstall the carburetor to the engine using a new gasket 11 Adjust the carburetor as outlined under the Adjustment portion of this section GOVERNOR Magnum engines are equipped with a centrifugal fly weight mechanical govemor It is designed to hold the engine speed constant under changing load con ditions The governor gear flyweight mechanism is mounted within the crankcase and is driven off the gear on the camshaft Refer to Figure 6A 16 Cross Governor Shaft Spring Governor Gear Assembly Regulating Pin Carburetor Throttle Lever Figure 6A 16 Centrifugal Flywelght Mechanical Governor NOTE Earlier models only
75. eather hose seals tightly in air cleaner base and breather cover to prevent unfiltered air from entering engine Air Cleaner Base Breather Hose Self Tapping Screw Figure 11 50 Installing Air Cleaner Base 2 Install the paper element precteaner if so equipped element cover and element cover seals Refer to Figure 11 51 Element Cover Optional Precleaner Figure 11 51 Installing Alr Cleaner Element 3 Install the air cleaner cover and wing nuts Tight en the wing nuts 1 2 to 1 full turn after nuts contact cover Do not overtighten Refer to Figure 11 52 11 17 SECTION 11 REASSEMBLY Air Cleaner Cover Figure 11 52 Installing Alr Cleaner Cover INSTALL EXHAUST ELBOWS AND MUFFLERS 1 Install the gaskets exhaust elbows and hex socket screws Torque screws to 150 In Ib Re fer to Figure 11 53 I Hex Socket he Screws Exhaust Elbow Figure 11 53 Installing Exhaust Elbows 11 18 2 Install the exhaust pipes and mufflers Refer to Figure 11 54 Muffler Muffler Exhaust Exhaust Pipe Pipe Spark Plug Spark Plug Lead Lead Exhaust Elbow Filter Oil Drain Plugs Figure 11 54 Installing Mufflers Filter Oil Drain and Spark Plug Leads INSTALL OIL FILTER NOTE The instructions given here are for the basic spec engine with the engine mounted oil filter If the engine is equipp
76. ed with an optional re mote oil filter system refer to Section 7 in this manual for installation details 1 Apply a thin coating of oil on the surface of the rubber seal 2 Tum the filter clockwise until rubber seal contacts the filter adapter then tighten filter an additional 1 2 tum 3 Add an additional 1 2 pint of oil for the filter capacity PREPARE THE ENGINE FOR OPERATION The engine is now completely reassembled Before Operating the engine be sure to do the following C Make sure ali hardware is tightened securely and oil drain plugs are installed O Fill the crankcase with the correct amount weight and type of oil Refer to the oil recommendations and procedures in the Safety and General Infor mation and Periodic Maintenance Sections D Adjust the carburetor main fuel needle idle fuel needle or idle speed adjusting screw as neces sary Refer to the Fuel System and Governor section D Make sure the maximum engine speed does not exceed 3600 RPM Adjust the high speed stop as necessary Refer to the Fuel System and Govemor Section SECTION 11 REASSEMBLY TESTING THE ENGINE It is recommended that the engine be operated on a test stand or bench prior to installation in the piece of equipment 1 Set the engine up on a test stand Install an oil pressure gauge in the location normally used for Oil Sentry Refer to Lubrication System Sec tion Figure 6 4 Start the engine and check to be
77. emove base from air intake elbow and intake manifold 2 Remove the valve cover and breather assembly fram the 1 cylinder barrel Remove the valve cover from the 2 cylinder barrel 3 Remove the spark plugs Measure Valve to Tappet Clearance IMPORTANT The piston must be at top dead center TDC of the compression stroke to measure valve to tappet clear ance By rotating the flywheel and observing the valves and tappets for movement it can be deter mined if a cylinder is at TDC If for example the flywheel is rotated and movement is noticed in the 2 side valve box the opposite cyl inder 1 side will be at TDC and valve to tappet clearance can be measured Rotating the flywheel one complete revolution 360 will then cause movement in the 1 side valve box the 2 side cylinder will be at TDC enabling measure ment of valve to tappet clearance for that side Clearance Specifications Intake Valve Closest to Flywheel 003 006 Exhaust Valve Seria No 1816500646 and earller Closest to PTO 016 019 Exhaust Valve Serial No 1816500656 and later Closest to PTO 011 014 1 Retate the flywheel and look into the valve boxes The valves and tappets will move in only one of the boxes Measure the valve to tappet clear ance for the cylinder in which no movement was Observed use a flat feeler gauge Refer to Figure 3 11 SECTION 3 PERIODIC MAINTENANCE 2 Rotate the flywheel 360 and meas
78. eplace Service With 1816500656 and later 52 012 08 Camshaft 52 012 07 Camshaft 52 012 08 Camshaft 52 019 02 Tappet 4 52 019 03 Tappet 4 52 019 02 Tappet 4 1816500646 and earlier 82 755 09 Camshaft Kit kit 82 755 09 contains the 52 012 08 camshaft and 52 019 02 tappets 4 Valve to Tappet Cold Clearance Intake 003 006 in 011 014 in 52 012 07 Camshaft 2003 006 in 52 019 03 Tappets When installing the camshaft from the 82 755 09 kit make sure the new tappets are also installed The Small Diameter new camshaft cannot be used with the original Drift Punch 52 019 03 tappets Set the valve to tappet clearance as specified above Engines Equipped With 52 012 08 Camshaft 52 019 02 Tappets 016 019 in NOTE The engine must be co d when setting valve to tappet clearance OIL PUMP Inspection and Service Check oil pump gear for any cracked chipped or badly worn teeth Replace gear if any of these prob lems exist See Figure 10 19 for oil pump gear removal Figure 10 19 Removing the Oll Pump Gear 10 14 SECTION 10 INSPECTION AND RECONDITIONING Check oil pump relief valve ball seat and spring refer NOTE An oil relief valve repair kit is available which to Figure 10 20 Ball and seat should be free of contains a new spring check ball and sleeve nicks or burrs Check spring for wear or disto
79. equiva lent to threads of switch install reducer to switch and tighten securely 3 Apply Loctite amp No 592 Teflon sealant or equiva lent to threads of reducer Install reducer switch assembly into crankcase Tighten the reducer securely into the crankcase Testing The pressure switch is a normally closed type calibrated to open break contact with increasing pressure and close make contact with decreasing pressure within the range of 2 0 5 0 psi Compressed air a pressure regulator a pressure gauge and a continuity tester are required to test the Switch 1 Connect the continuity tester across the blade ter minal and metal case of switch With O psi pres sure applied to switch the tester should indicate continuity Switch closed 2 Gradually increase the pressure to the switch The tester should indicate a change to no continu ity switch open as the pressure increases through the range of 2 0 5 0 psi The switch should remain open as pressure is increased to 90 psi maximum 3 Gradually decrease the pressure to the switch The tester should indicate a change to continuity switch closed as the pressure decreases through the range of 2 0 5 0 psi approaching 0 psi 7 4 M18 amp M20 SECTION 8 ELECTRICAL SYSTEM AND COMPONENTS MAGNUM ELECTRONIC MAGNETO IGNITION SYSTEM This engine is equipped with a state of the art elec tronic magneto ignition system The system consists of the follo
80. er adapter and hex sock et head screws Make sure the on filter adapter is pointing to top of crankcase Refer to Figure 11 25 Installation Oil Filter Adapter Figure 11 25 Installing Oil Filter Adapter 2 Torque the hex socket head screws to 75 90 In Ib NOTE Refer to the Lubrication System section for installation torques of remote oil filter and oil filter bypass components INSTALL OIL PRESSURE RELIEF VALVE CLOSURE PLATE AND REAR OIL SEAL NOTE Later production models use silicone sealant as a gasket between the closure plate and crankcase In order to eliminate the fiber gas ket and use sealant an additional 020 of material was added to the closure plate Therefore closure plates designed for use with gaskets cannot be installed using sea lant closure plates designed for use with sea lant cannot be installed using a gasket Follow these general guidelines when reinstalling or replacing closure plates When reinstalling a closure plate originally in stalled using a gasket use a new gasket When reinstalling a closure plate originally in stalled using sealant or installing a service re placement closure plate kit apply a new bead of sealant to the closure plate as shown in Figure 11 27 1 Instali the oil pressure relief valve sleeve steel ball and spring Refer to Figure 11 26 2 Make sure the mating surfaces of the crankcase and closure plate are cleaned
81. ess than 90 psig 2 Set the throttle and choke controls to the wide check for the conditions below open position Make sure air cleaner and exhaust system are not restricted LOW COMPRESSION Possible Cause Solution 1 Blown cylinder head gaskets 1 Remove cylinder heads Inspect heads for flatness replace heads if necessary replace gaskets re Install heads and recheck compression Locate and correct the cause of initial failure 2 Warped or loose cylinder heads 2 Remove cylinder heads check for flatness replace heads if necessary Make sure cylinder head fas teners are torqued in the proper sequence to the proper value 3 Excessive combustion chamber deposits 3 Remove cylinder heads and clean deposits from combustion chamber 4 Wom piston rings blowby occurring 4 Recondition piston rings and cylinder bores 5 Wom valves 5 Recondition valves and valve seals 4 4 SECTION 4 TROUBLESHOOTING Cylinder Leakdown Test A cylinder leakdown test can be a valuable altemative to a compression test By pressurizing the combus tion chamber from an extemal air source you can de termine if the vatves or rings are leaking and how badly The Kohler Part No 47 800 02 is a relatively simple inexpensive leakdown tester for small engines The tester includes a quick disconnect for attaching the adapter hose and a holding tool Leakdown Test Instructions 1 Run engine for 3 5 minutes to
82. ests on the fuel inlet needle The exposed surface of float should be parallel with the bowl gasket surface of the carburetor body exposed free end of float 690 720 from bowl gasket sur face Refer to Figure 6B 14 6B 9 SECTION 6B FUEL SYSTEMS i Needle w cllp Installed Needle w clip on float adj tab Installing tloat needle well Bend Tab To Aqu Parallel Parallel p e Bowl Gasket P 4 Figure amp B 14 Setting Fiost Level Bend the float tab with a small screwdriver to adjust 5 Install a new bowl gasket and the fuel bowl Make sure the bowl gasket and bowl are centered and positioned properly to ensure a good seal 6 Install a new bow retaining screw gasket and the bowl retaining screw Torque screw ta 45 55 In Ib 7 Install the idle speed adjusting screw and spring Figure 6B 13 Fuel Needle Clip 8 Install the idle fuel adjusting needle and spring Turn the adjusting needle In clockwise until it bottoms lightly NOTE The tip of the idle fuel adjusting needle is tapered to critical dimensions Damage to the needle and the seat in carburetor body will result if the needle is forced 9 Tum the idle fuel needle out counterclockwise from lightly bottomed according to the instructions in the Adjustment portion of this Section High Altitude Operation Fixed Main Carburetors When
83. etorque the hex nuts on Posi Lock connect ing rods Torque the nuts in increments di rectly to the specifled values INSTALL BEARINGS AND CRANKSHAFT 1 Lubricate the crankshaft bearing journals with en gine oil Install the 130 thrust washer to end of crankshaft Refer to Figure 11 11 Sleeve Bearings PTO End Connecting Rods Thrust Washer Figure 11 11 Installing Thrust Washer and Bearings to Crankshaft 2 Install the bearings to PTO and flywheel end of crankshaft 3 Install the crankshaft with connecting rods and bearings into crankcase Make sure the locating tab of PTO end sleeve bearing is positioned in notch in crankcase refer to Figure 11 12 The oil hole in flywheel end sleeve bearing must be aligned with the oil gallery in crankcase refer to Figure 11 13 PTO Sleeve Bearing econ Figure 11 12 Position of PTO Bearing Measuring Crankshaft End Play With Gallery Hole Must Be ux d Figure 11 13 Position of Flywheel Bearing NOTE Improper positioning of bearings could result in engine failure due to lack of lubrication 4 Measure the crankshaft end play with a flat feeler gauge The recommended crankshaft end play is 002 014 Exchange thrust washer if necessary to bring end play within range Three sizes of thrust washers are available 121 130 STD and 139 Roller Thrust Bearings Some engines for high th
84. f crankcase as this can cause leaks REMOVE CAMSHAFT AND TAPPETS 1 Remove the camshaft and camshatt bore plug from the 1 crankcase side Refer to Figure 9 33 Figure 9 33 Removing The Camshatt and Camshaft Bore Plug 2 With a marking pen or paint mark the tappets ac carding to crankcase side and as either intake or exhaust Remove tappets from both crankcase sides Refer to Figure 9 34 9 10 Rear Bearing Crankshatt With Connecting Rods Figure 9 34 Removing Tappets Crankshaft Front Oil Seal and Bearings NOTE The intake valve tappet is Closest to the fly wheel side of crankcase The exhaust valve tappet is closest to the PTO side of crankcase REMOVE CRANKSHAFT FRONT OIL SEAL AND BEARINGS 1 Remove the crankshaft with connecting rods bearings and front oil seal from the 1 crankcase side Refer to Figure 9 34 2 Remove the front oil seal from the flywheel end of crankshaft Remove bearings and thrust washer from crankshaft SECTION 9 DISASSEMBLY REMOVE CONNECTING RODS NOTE Loosen the clamp securing dipstick tube 1 With a marking pen or paint mark the connecting to crankcase Move the dipstick tube out Tods and rod caps as 1 side and 42 side On of the way to ease removal of stop M18 mark which side is top 2 Remove the governor gear and thrust washer from 2 Remove the hex nuts connecting rod caps and stub shaft Refer to Figure 9 37 connecting rods fro
85. g Crankshaft and Cam Gear Timing Marks 4 Measure the camshaft end play with a flat feeler gauge The recommended camshaft end play is 003 013 Refer to Figure 11 17 Add shim spacers if necessary to bring end play within range n Camshatt Flat Feeler Gauge Figure 11 17 Measuring Camshaft End Play INSTALL CAMSHAFT BORE PLUG AND SEAL CRANKCASE 1 Prepare the sealing surfaces of the crankcase sides and mating surfaces of crankcase and cylin der barrels as directed by the sealant manufacturer NOTE Do not scrape the surfaces when cleaning as this will damage the surfaces causing leaks The use of a gasket removing sol vent is recommended 2 Apply a 1 16 bead of sealant to the 42 crankcase side as shown in Figure 11 18 Follow the sea lant manufacturer s recommendations regarding setting Recommended sealants are listed below 2 Crankcase Side Sealant n Gallery 1 In 1 Side Sealant Sealant iy DT TOU Figure 11 18 Crankcase Sealant Pattern SECTION 11 REASSEMBLY Recommended Sealants These commercially available sealants are recommended for use on MAGNUM M18 and M20 engines VENDOR PRODUCT VENDOR NO amp DESCRIPTION AVAILABILITY Dow Corning Silicone Rubber Sealant 732 Aluminum Black Bronze Clear Automotive Hardware White and Discount Stores GE
86. gaskets when servicing and reinstall ing carburetors Repair kits are available which in clude new gaskets and other components These kits are described below Components such as the throttle and choke shaft as semblies throttle plate choke plate idle fuel needle main jet and others are available separately Refer to the appropriate Parts Manual to ensure the correct carburetor repair kits and replacement parts are ordered Carburetor Repair Kit No 25 757 11 For WHG Serles 1 Contains Qty Description Gasket carburetor 3 different styles Gasket air cleaner 4 different styles Gasket fuel bowl Gasket bowl retaining screw Plug 3 8 dia welch Plug 5 16 dia welch Needle fuel inlet Valve fuel inlet assembly annuum Float Assembly Kit No 25 757 09 For WHG Serles Carbs Contains Qty Description 1 Float Assembly 1 Float Pin Reassembly Throttle Shaft Installation 1 Install the foam dust seal on throttle shaft Insert the throttle lever shaft assembly into carburetor body with the cutout portion of shaft facing the carburetor mounting flange 2 Install the throttle plate to throttle shaft Make sure the plate is positioned property in bore as marked and noted during disassembly the numbers stamped on plate should face the carburetor mounting flange Apply Loctite 609 to threads of 2 plate retaining screws Install screws so they are slightly loose 3
87. gure 8 8 Wire Gauge Ground Etectrode gr ORE 0 035 Gap Figure 8 8 Servicing Spark Plug SECTION 8 ELECTRICAL SYSTEM AND COMPONENTS 1 Before removing the spark plugs clean the area around the base of plugs to keep dirt and debris out of the engine 2 Remove the plugs and check condition Replace the plugs if wom or if reuse is questionable Use Champion type RV17YC or equivalent spark plugs NOTE Do not clean the spark plugs in a machine using abrasive grit Some grit could re main in spark plugs and enter the engine causing extensive wear and damage 3 Check the gaps using a wire feeler gauge Adjust gaps to 0 035 0 89 mm by carefully bending the ground electrode 4 Reinstall the spark plugs Into cylinder heads Torque plugs to 10 15 ft Ib 14 20 Nem INSPECTION Inspect the spark plugs as soon as they are removed from the cylinder heads The deposits on the tips are an indication of the general condition of piston rings valves and carburetor Normal and faulty spark plugs are shown in the follow ing photos Normat A plug taken from an engine operating under nor mal conditions will have light tan or gray colored deposits If the center electrode is not worn a plug in this condition could be regapped and reused Carbon Fouled Soft sooty black deposits indicate incom plete combustion Incomplete combustion is usually caused by over r
88. h insert 48 755 23 13 tooth insert 48 755 21 OIL SENTRY OIL PRESSURE MONITOR Some engines are equipped with the optional Oil Sentry oil pressure monitor Oil Sentry will either Stop the engine or activate a low oil waming light if the oil pressure gets low Actual Oil Sentry use will depend on the engine application Operation Oil Sentry uses a pressure switch in one of the main crankcase ail galleries to detect low oil pressure At Gil pressures below approximately 3 1 2 psi the pres sure switch closes At oil pressures above approxi mately 3 1 2 psi the pressure switch opens On stationary or unattended applications pumps generators etc the pressure switch can be used to ground the ignition module to stop the engine On vehicular applications garden tractors mowers etc the pressure switch can be used to activate a low oil waming light NOTE Oil Sentry is not a substitute for checking oil level BEFORE EACH USE Make sure the oil level is maintained up to the F mark on dip Stick Installation The pressure switch is installed in the oil gallery lo cated near the dipstick tube and closure plate on the 1 side of crankcase refer to Figure 7 5 On engines not equipped with Oil Sentry the oil gallery Is sealed with a 1 16 N PT F pipe plug 1 Remove the 1 16 pipe plug or old switch and reducer from crankcase 2 Apply Loctite amp No 592 Teflon sealant or
89. hat were built before the permanent alignment pins were add ed use the available alignment pin tools when install ing new or serviced closure plates Hobart Welders use Part No 52 455 05 pins while all other splined shaft specifications use 52 380 06 pins The closure plate kits which are available for these earlier engines include the pins and instructions for using Follow preceding instructions for reinstalling the clo sure plate however before tightening the plate and before installing the oil seal insert the four alignment pins into four equal distant locations between the crankshaft seal surface and the closure plate outer circumference If any pins become tight shift the clo sure plate to allow all pins to position equally against crankshaft sealing surface After aligning tighten clo sure plate screws as specified in Step 4 Remove the pins after tightening the closure plate to allow install ing the oil seal INSTALL PISTON RINGS NOTE For detailed piston inspection procedures and piston ring installation procedures refer to the Inspection and Reconditioning Section INSTALL PISTONS IN CYLINDER BARRELS NOTE Proper orientation of the pistons within cylin der barrels is extremely important Improper orientation may Cause extensive wear or damage 1 Stagger the piston rings in grooves until the end gaps are 120 apart 2 Lubricate the pistons and rings with engine oil Install piston ring compressor ar
90. he bore start drill and honing process Move hone up and down while resizing to prevent formation of cutting ridges Check size frequently 10 2 NOTE Keep in mind the temperatures caused by honing may cause inaccurate measure ments Make sure the barrel is cool when measuring 3 When bore is within 0025 of desired size re move coarse stones and replace with burnishing stones Continue with bumishing stones until within 0005 of desired size and then use finish stones 220 280 grit and polish to final size A crosshatch should be observed if honing is done correctly The crosshatch should intersect at ap proximately 23 33 off the horizontal Too flat of an angle could cause the rings to skip and wear excessively too steep of an angle will result in high oil consumption refer to Figure 10 2 Figure 10 2 Cylinder Bore Crosshatch After Honing 4 After resizing check the bore for roundness taper and size Use an inside micrometer telescoping gauge or bore gauge to take measurements Re fer to Figure 10 3 The measurements should be taken at three locations in the cylinder at the top middle and bottom Two measurements should be taken perpendicular to each other at each of the three locations NOTE Your final bore size should be exactly 003 010 020 or 030 over standard size Service replacement pistons are manufactured to precise tolerances to match those sizes SECTION 10 INSPECTIO
91. he pis ton pin See Figure 10 11 Also the piston pin bosses are thicker than other styles of similar pistons Figure 10 11 Style D Piston NOTE The Posi Lock connecting rods used with the style D pistons are narrower at piston pin end 1o accommodate the increased piston pin boss thickness See Posi Lock Connecting Rods elsewhere in this section 10 9 SECTION 10 INSPECTION AND RECONDITIONING Inspection Scuffing and scoring of pistons and cylinder walls oc curs when intemal temperatures approach the welding point of the piston Temperatures high enough to do this are created by friction which is usually attributed to improper lubrication and or overheating of the engine Normally very little wear takes place in the piston boss piston pin area If the original piston and con necting rod can be reused after new rings are in stalled the original pin can also be reused but new piston pin retainers are required The piston pin is included as part of the piston assembly if the pin boss in piston or the pin are wom or damaged a new piston assembly is required Ring failure is usually indicated by excessive oil con sumption and blue exhaust smoke When rings fail oil is allowed to enter the combustion chamber where it is bumed along with the fuel High oi consumption can also occur when the piston ring end gap is incor rect because the ring cannot properly conform to the cylinder wall under this condition O
92. he ring gear into the retracted position Starter Removal and Reinstallation Refer to the engine disassembly and reassembly sec tions later in this manual for starter removal and instal lation procedures Magnet switch Drive lever Drive housing Stop collars Yoke Front bushing Snap ring End frame Clutch Rear bushing Brush spring ex Cover insulator Brush holder Thru bolt Figure 8 21 Exploded View of Nippensenso Solenold Shift Starter 8 16 SECTION 8 ELECTRICAL SYSTEM AND COMPONENTS Starter Disassembly 1 Disconnect the wire from the solenoid Drive lever 2 Remove the hex nuts securing the solenoid and remove the solenoid from the starter assembly 3 Remove the two thru bolts 4 Remove the commutator end cap 5 Remove the insulator and brush springs from the brush spring holder Insulator Move the pivot of pliers to the jaws Brush spring Brush maximum opening position Figure 8 22 Removing the Insulator Figure 8 24 Removing the Stop Collar 1 6 Remove the armature trom the frame 8 The stop collar consists of two similar pieces held in place by being snapped over a retainer The 7 Remove the drive lever and armature trom the retainer is held in place by a groove in the arma drive end cap ture shaft To remove the stop collar the two pieces must be prieg off the retainer NOTE When removing the teve
93. her and govemor stop pin Refer to Figure 11 9 Stop Pin Copper Washer Dipstick Tube Clamp Figure 11 9 Installing Governor Stop Pin NOTE If nat loosened during disassembly loosen the clamp securing the dipstick tube to crank case Move the dipstick tube out of the way to ease installation of stop pin Tighten the clamp securely after installing stop pin INSTALL CONNECTING RODS 1 Lubricate the connecting rod journals and studs with engine oil and instali connecting rods to crankshaft e When Reinstalling Used Rods Install the 1 connecting rod to crankshaft joumal closest to flywheel end of crankshaft Install 2 connect ing rod to the journal closest to PTO end of crankshaft On Model M20 Insiall the connecting rods with the shanks angled down and away from the camshaft top of crankcase Refer to Figure 11 10 SECTION 11 REASSEMBLY r Posi Lock Connecting Rods Dowel Sleeve un M18 Match Marks Shank Angled Down And Away From Camshaft M20 Match Marks Figure 11 10 Installing Posi Lock Connecting Rods 2 Install the connecting rod caps Make sure the match marks are aligned and the proper cap is reinstalled to each connecting rod 3 Install the hex nuts and torque as follows Torque New Service Rod 140 In Ib Used Reinstalled Rod 100 in Ib NOTE To prevent damage to the connecting rods and engine do not overtorque ioosen and r
94. hes top RPM and stop NOTE Setting the idle mixture screw halfway be tween the two ranges will cause a rich mixture setting SECTION 6A FUEL SYSTEMS AND GOVERNORS C Increase engine RPM to the high speed set ting of 3600 Apply a load and adjust the high speed mixture screw at the adapter see Figure 6A 24 as follows Tum high speed mixture screw OUT toward the rich side until engine RPM drops this should be confirmed with tachometer Then tum screw IN toward lead side until engine RPM recovers and begins to fall off At this point again tum the screw OUT just until en gine reaches top RPM and stop It this procedure is used correctly tne unit will now be adjusted to LEAN BEST POWER d When using a dual fuel adapter with a gaso line carburetor the gasoline carburetor mixture setting will need to be adjusted from that of the factory LPG CARBURETOR Some M18 amp M20 Engines are equipped with Kohler built Liquid Propane Gas LPG carburetors as shown in Figure 6A 25 On applications using this carbure tor the equipment manufacturer furnishes the regula tors fuel tank and other LPG system components Use the part number stamped on the body of the car buretor for ordering the correct replacement compo nents for the carburetor involved as listed in the M18 amp M20 parts manual The Venturi fuel inlet fitting adjusting needles screws and springs can be replaced on these carburetors however the throttle
95. ich carburetion weak ignition or poor compression SECTION 8 ELECTRICAL SYSTEM AND COMPONENTS Worn On a worn plug the center electrode will be rounded and the gap will be eroded 010 or more than the correct gap Replace a wom spark plug immediately the combustion chamber Excess fuel could be caused by operating the engine with too much choke Oil in the com bustion chamber is usually caused by worn piston rings or valve guides NOTE For repeated spark plug fouling order and install Carburetor Baffle Kit 82 755 24 Chalky White Deposits Chatky white colored deposits indi cate overheating This condition is usually accompanied by excessive gap erosion A clogged grass screen clogged cooling fins and lean carburetion are some causes of overheating ELECTRICAL SYSTEMS WIRING DIAGRAMS AND BATTERY CHARGING SYSTEMS The following battery charging systems are available on Magnum twin cylinder engines D 15 Amp Regulated Battery Charging System O 25 Amp Regulated Battery Charging System Refer to the following wiring diagrams and trouble shooting guides to test and service these battery charging systems NOTE To prevent damage to the electrical system and components 1 Make sure battery polarity is correct A nega tive ground system is used 2 Disconnect the rectifier regulator leads and or wiring hamess plug before electric welding is done on the equipment powered
96. icing the carburetor engine or equip ment always remove the spark plug leads to prevent the engine from starting accidentally Ground the leads to prevent sparks that could cause fires A WARNING Explosive Fuell Gasoline may be present in the carburetor and fuel system Gasoline is extremely flammable and its vapors can explode if ignited Keep sparks open flame and other sources of ignition away from the area to prevent the possibility of fires or explosions A WARNING Prevent Eye Injury Suitable eye protection safety glasses goggles or face shield should be worn for any procedure in volving the use of compressed air punches ham mers chisels drills or grinding tools 6B 1 SECTION 68 Series Designation Kohler Part No NOTE These will be on either the top throttle Date Code lever side of mounting flange as shown or on AL x the bottom fuel bowl side of mounting flange Dee Throttle Lever Shaft Assembly Idie Fuel Adjusting Needle And Spring Choke Lever Shaft Assembly Choke Plate Lars Fuel Bowl Choke Detent Bail And Spring Idle Speed Adjusting X Fuel Bowl Retalning Screw And Spring Screw And Gasket Idle Fuel Outlet Port ing FI Mounting Flange Fuel Bowl Gasket Float Pin Float gt Ott Idle Throttle Plate Float Level Fioat Drop _ Port Adjusting Tab Limiting Tab Non Adjustabie Idle Air Bleed Bow Vent Float Hinge Nozzl
97. igure 6A 19 clockwise as far as it will go 3 Tighten the palnut on govemor arm to 15 In Ib torque HIGH SPEED ADJUSTMENT The maximum allowable speed is 3600 RPM no load The actual high speed setting depends on the appli To Increase i cation Refer to the equipment manufacturer s instruc Speed tions for specific high speed settings Check the operating speed with a tachometer do not exceed the EM maximum To adjust high speed stop High Speed Stop Bracket To Decrease Speed For Remote Throttle Control Early Tab Version figure 6A 19 High Speed Adjustment Engine NOTE High Speed Stop Tab as shown in Figure Mounted Throttle Control and Later Remote Mounted 6A 18 used only on earlier models Later 2 Slide bracket until the desired speed is reached models all use high speed stop bracket ie 3 Make sure the bracket is resting against boss on shown in Figure Lorie It engine avowed intake elbow and tighten hex cap screw securely has bracket type adjust high speed foltowing instructions for Engine Mounted Throttle ily speed with the tachometer readjust if Control 1 Loosen the hex cap screw securing high speed Stop tab to intake elbow Refer to Figure 6A 18 6A 13 SECTION 6A FUEL SYSTEMS AND GOVERNORS SENSITIVITY ADJUSTMENT Govemor sensitivity is adjusted by repositioning the governor spring the holes in governor arm If set too sensitive speed surging will occur with a
98. il control is also lost when ring gaps are not staggered during installation 10 10 When cylinder temperatures get too high lacquer and vamish collect on pistons causing rings to stick which results in rapid wear A wor ring usually takes on a shiny or bright appearance Scratches on rings and pistons are caused by abrasive material such as car bon dirt or pieces of hard metal Detonation damage occurs when a portion of the fuel charge ignites spontaneously from heat and pressure shortly after ignition This creates two flame fronts which meet and explode to create extreme hammering pressures on a specific area of the piston Detonation generally occurs from using low octane fuels Preignition or ignition of the fuel charge before the timed spark can cause damage similar to detonation Preignition damage is often more severe than detona tion damage Preignition is caused by a hot spot in the combustion chamber from sources such as glow ing carbon deposits blocked fins improperly seated valves or wrong spark plugs See Figure 10 12 for some common types of piston and ring damage SECTION 10 INSPECTION AND RECONDITIONING Stuck Broken Rings Abrasive Scratched Rings Scored Piston and Rings Figure 10 12 Common Types of Piston and Ring Damage Service Some important points to remember when servicing piston rings 1 If the cylinder block does not need reboring and if the old piston is within we
99. in Ib 70 in ib 1 4 20 70 in 1i5in Ib 165in Ib 5 16 18 150 in Ib 150in Ib 150in Ib 1 4 28 85 in 140 in Ib 200 in Ib 5 16 18 150 in 250 in Ib 350in Ib Oil Drain Plugs 5 16 24 165 in 270 in Ib 30 ft Ib 3 8 16 260in 350 10 50 ft Ib size Into Cast Iron Pans Into Aluminum Pans 3 8 24 300 in 40 ft Ib 60 ft Ib 1 4 150 in Ib 100 in Ib 7 16 14 35 ft 55 ft Ib 80 ft Ib 3 8 180 in Ib 120 in Ib 7 16 20 45ft 75 ft Ib 105 ft Ib 1 2 20 ft Ib 13 ft Ib 1 2 13 50 ft 80 ft Ib 115 ft Ib 25 ft Ib 16 ft Ib 1 2 20 70 ft 105 ft Ib 165 ft Ib X 708 15 20 25 ft Ib 20 25 ft Ib 9 16 12 75 ft 125 ft Ib 175 ft tb 9 16 18 100ft 165 ft Ib 230 ft tb Conversions 5 8 11 1100 180 ft Ib 260 ft Ib ft Ib in Ib x 0 083 5 8 18 140 ft 230 ft Ib 330ft Ib in Ib 3 4 10 150 ft 245 ft Ib 350 ft Ib kgm 3 4 16 200 ft 325 ft Ib 470 ft Ib Nem ft Ib x 1 3558 M18 amp M20 SECTION 2 SPECIAL TOOLS SPECIAL SERVICE TOOL KIT NO 3211 These quality tools are designed to help you perform specific disassembly repair and reassembly proce dures By using tools designed for the job you can service engines easier faster and safer In addition you ll increase your service capabilities and customer satisfaction by decreasing engine down time The Special Service Tool Kit No 3211 can b
100. in washer and fiber washer from the stud terminal Remove the stud terminal with positive brushes and plastic insulating bushing from end cap Reinstall the insulating brushing to new stud termi nal with positive brushes Install the bushing and stud terminal into end cap Secure with the fiber washer plain washer split lock washer and hex nut Install the brush holder and new negative brushes Secure with the self tapping screws gt a Ld Instali the brush springs and brushes into the pockets in brush holder Make sure the cham fered sides of brushes are away from the springs NOTE Use a brush holder tool to keep the brushes in the pockets A brush holder tool can easily be made from thin sheet metal Refer to Figure 8 19 Sheet Metal Brush Holder Brush Holder Installed 7 Over Brushes And End Cap Figure 8 19 Brush Holder Tool Commutator Service Clean the commutator with a coarse lint free cloth Do not use emery cloth If the commutator is badly wom or grooved turn down on a lathe or replace the armature Reassembly 1 Insert the armature into the starter frame Make sure the magnets are closer to the drive shaft end of armature The magnets will hold the armature inside the frame 2 Install the thrust washer and drive end cap Make sure the match marks on end cap and frame are aligned Refer to Figure 8 20 Match Marks Match Marks Comm
101. ing pen Also take note of choke plate position in bore and choke lever position 2 Carefully and slowly remove the screws securing choke plate to choke shaft Remove and save the choke plate as it will be reused 3 File off any burrs which may have been left on choke shaft when screws were removed Place carburetor on workbench with choke side down Remove choke shaft the detent ball and spring will drop out 4 Note the position of the choke lever with respect to the cutout portion of choke shaft 5 Carefully grind or file away the riveted portion of shaft Remove and save choke lever discard old choke shaft 6 Install choke lever to new choke shaft from kit Make sure lever is installed correctly as noted in Step 5 Apply Loctite amp to threads of 1 43 48 x 7 32 brass screw secure lever to shaft 6A 7 SECTION 6A FUEL SYSTEMS AND GOVERNORS Throttle Shaft 4 Styles Choke Shaft Bushing Bras Choke Detent Ball And Spri Te all And Springs Sew 3 48x7 32 Choke Flate Brass Screws 7 Ber BIN A Choke Shaft Bushing Choke Shaft Choke Lever Reused 2 56x7 32 or 3 48x7 32 Brass Screw For Models M18 and M20 1 Carb 3 48 7 32 7 Battie Gasket i 2 56x7 32 or 43 48x7 32 Brass Screw SS Throttle Lever Reused 5 Screws aA Bow Gasket E Throttle Shaft Bushing Installation Tool Figure 6A 8 Throttle and Choke Shaft Replacement Ki
102. ing pin will again be in equilibrium This maintains engine speed amp t a relatively constant level Govemed speed may be at a fixed point as on con stant speed applications or variable as determined by a throttle control lever Adjustment A WARNING Overspeed Is Hazardous The maximum allowable speed for these engines is 3600 RPM no load Never tamper with the governor settings to increase the maximum speed Severe personal injury and damage to the engine or equip ment can result if operated at speeds above maximum 6A 12 SECTION 6A FUEL SYSTEMS AND GOVERNORS INITIAL ADJUSTMENT Make this initial adjustment whenever the governor arm is loosened or removed from cross shaft Make sure the throttle linkage is connected to governor and throttle lever on carburetor to ensure proper set ting Refer to Figure 6 17 High Speed Stop Tab Figure 6A 18 High Speed Adjustment Remote Throttle Control Early Tab Version 2 Pivot the high speed stop tab until the desired v speed is reached Governor 3 Tighten the hex cap screw tightly Arm For Engine Mounted Throttle Control Figure 6A 17 Initial Governor Adjustment and Later Remote with Stop Bracket 1 Pull the govemor arm away from the carburetor as 1 Loosen the hex cap screw securing the high far as it will go speed stop bracket to intake elbow Refer to 2 Grasp the end of cross shaft with pliers and turn F
103. ing the ground electrode 4 Reinstall spark plugs into cylinder heads Torque plugs to 10 15 ft Ib IGNITION SYSTEM SERVICE Magnum engines are equipped with a dependable electronic magneto ignition system Other than peri odically checking replacing the spark plugs no main tenance timing or adjustments are necessary or possible with this system CHECK FUEL FILTER Fuel Filter Figure 3 7 In line Fuel Filter Some engines are equipped with an in line fuel filter Visually inspect the filter periodically Replace when dirty with a genuine Kohler filter SERVICE STARTER MOTOR DRIVE Every 500 operating hours or annually whichever oc curs first clean and lubricate tne drive splines of the Bendix drive electric starter motor Refer to Figure 3 8 S Splines Drive Shaft Drive Pinion Stop Gear Spacer Dust Cover NS Spacer ee Spring E Dust Cover Stop Nut Figure 3 8 Starter Drive Components 1 Remove starter from crankcase Refer to the Disassembly Section 2 Remove dust cover stop nut stop gear spacer spring Gust cover spacer and drive pinion 3 5 SECTION 3 PERIODIC MAINTENANCE 3 Clean the drive shaft splines with solvent Dry splines thoroughly 4 Apply a small amount of Kohler electric starter drive lubricant Part No 52 357 01 to splines NOTE Kohler starter drive lubricant Part No 52 357 01 must be used on all Kohler e
104. ion until desired position is reached 2 Install new gasket fuel pump and truss head ny Jock screws NOTE Make sure the fuel pump lever is posi tioned above the camshaft Damage to the fuel pump and subsequent severe engine damage could result if the lever is positloned below the camshaft Torque screws to 40 45 In Ib 3 Connect fuel lines to inlet and outlet fittings CARBURETOR This subsection covers the adjustment disassembly cleaning inspection repair and reassembly of Kohler buitt side draft adjustable Jet carburetors n A WARNING Explosive Fuell Gasoline may be present in the carburetor and fuel system Gasoline is extremely flammable and its va pors can explode if ignited Keep sparks open flame and other sources of ignition away from engine Wipe up spilled fuel immediately Adjustment The carburetor is designed to deliver the correct fuel air mixture to the engine under all operating condi tions Carburetors are set at the factory and normally do not need adjustment If the engine exhibits condi tions like those found in the table on page 6A 4 it may be necessary to adjust the carburetor Tuming the adjusting needles In clockwise de creases the supply of fuel to the carburetor This gives a leaner fuel air mixture Turning the adjusting needles out counterclockwise increases the supply of fuel to the carburetor This gives a richer fuel air mixture Refer to Figures 6A 5 and 6A 8 NOTE In
105. ipstick and oil drain plug Drain the oil from crankcase Refer to Figure 9 1 2 Remove and discard the oil filter Oil Fill gt Exhaust Cap Pipe Muttler Spark Plug t Spark Plug Lead T Lead Dipstick Oil Filter Oil Drain Plugs Figure 9 1 Removing Spark Plug Leads Oil Drain Oil Filter and Mufflers 9 1 SECTION 9 DISASSEMBLY REMOVE MUFFLERS AND EXHAUST ELBOWS 1 Remove the mufflers and exhaust pipes Refer to Figure 9 1 2 Remove the hex socket screws exhaust elbows and gaskets Refer to Figure 9 2 28 Exhaust Figure 9 2 Removing Exhaust Elbows REMOVE AIR CLEANER NOTE The instructions given here are for the basic spec engine with the square style air cleaner If the engine is equipped with an optional style air cleaner refer to the Air Cleaner Sec tion for removal procedures 1 Remove the wing nuts and air cleaner cover Re fer to Figure 9 3 Air Cleaner Wing Cover P Figure 9 3 Removing Air Cleaner Cover 9 2 2 Remove the element cover seals element cover and paper element with precleaner if so equipped Refer to Figure 9 4 Element Cover Seals N Element Cover Figure 9 4 Removing Air Cleaner Element 3 Remove the breather hose self tapping screw air Cleaner base air intake tube and gasket Refer to Figure 9 5 Air Cleaner Base Breather Hose i Sett Tapping Screw
106. k screw enough to hold throttle lever In position while the engine is running Do not overtighten the screw the lever must operate smoothly Connect the choke linkage to choke lever on car buretor Loosely install choke control assembly to intake manifold with clamp and self tapping Screw Adjust Choke ControlI Make sure the choke knob is held against the hex head threads Move the assembly towards carburetor until the choke plate is wide open Tighten the self tapping screw securely 6A 15 SECTION 6A FUEL SYSTEMS AND GOVERNORS OPTIONAL AUTOMATIC CHOKE AND SHUTDOWN CONTROL in clockwise direction for richer setting or counter clockwise direction for leaner setting Tighten the cov er retainer screws Sore Magnum twins on may be equipped with an optional Thermo Electric Automatic Choke and with a Fuel Shutdown Control Automatic Choke Function The choke is an integral part of tne carburetor The choke will close automatically from ambient air Upon starting the engine vacuum will partially open the choke The bi metal spring in the choke is electrically connected to the rectifier regulator and the current flowing through the bi metal spring will heat to a point that the choke will open fully Automatic Choke Adjustment The choke unit Figure 6A 22 is set at the factory for average conditions To readjust for local conditions loosen the cover retaining screws and shift the cover Pr
107. ke sure the arrow on bracket is pointing to top of crankcase Refer to Figure 11 38 1 Cylinder Barrel Figure 11 38 installing ignition Module Bracket Rotate flywheel magnet away from module position 3 Install the module and hex flange screws to bracket Move module as far from flywheel as possible tighten hex cap screws slightly 4 Insert a 014 flat feeler gauge or shim stock be tween magnet and module Loosen the hex flange screws so magnet pulls the module against feeler gauge refer to Figure 11 39 Tighten the hex flange screws securely Remove the feeler gauge or shim stock Due to the pull of the mag net the magnet to module air gap should be within the final range of 008 012 11 14 Bron Feeler 3 li Hex Flange ih Screws Figure 11 39 Installing ignition Module 4 Rotate the flywheel back and forth check to make sure the magnet does not strike the module Readjust gap if necessary 5 install the kill lead to kill terminal on module INSTALL FUEL PUMP 1 Install the gasket fuel pump and truss head screws Refer to Figure 11 40 Fuel Pump Truss Head Figure 11 40 Installing Fuel Pump NOTE Make sure the fuel pump lever is posi tioned above the camshaft Damage to the fuel pump and subsequent severe en gine damage could result if the lever is Positioned below the camshaft 2 Torque screws to 40 45 In Ib SECTION 11
108. l oil filter adapter Install oil pressure relief valve closure plate and rear oil seal 10 Install piston rings 11 Install pistons in cylinder barrels 12 Install cylinder barrels 13 Measure valve to tappet clearance 14 Install valves 15 Install cylinder heads and spark plugs 16 Install stator 17 Install electric starter 18 Install fan flywheel and grass screen 19 Install bracket and ignition module SCONAHAYON A 20 Install fuel pump 21 Install valve cover and breather 22 Install blower housing cylinder head baffles and top baffle 23 Install solenoid key switch rectifier regulator and connect wiring 24 Install carburetor and intake manifold 25 Install air cleaner 26 Install exhaust elbows and mufflers 27 install oil filter INSTALL O L PUMP AND OIL PICKUP Oil Pump 1 Install the shim spacer next to support rib oil pump drive gear slotted end of gear hub towards spacer and rib and oil pump drive shaft through support rib and into pump cavity Refer to Figures 11 1 and 11 2 Roll Pin d Q Gear Spacer Figure 11 1 Installing Oil Pump Drive Gear 2 Rotate the drive shaft and drive gear until hole in shaft is aligned with slot in gear hub 3 Lubricate a new roil pin with grease Drive the roll pin until it is flush with gear hub Refer to Figure 11 2 SECTION 11 REASSEMBLY Figure 11 2 Securing Pump Drive Ge
109. l the way down into tube Re move dipstick and check the level The oil level should be up to but not over the F mark on the dipstick Refer to Figure 3 1 3 1 SECTION 3 PERIODIC MAINTENANCE Operating P Range 6 p E X Figure 3 1 Oil Level Range 4 Add the proper type of oil if the level is low Al ways check the level with dipstick before adding more oil NOTE Never operate the engine with the oil level below 1 mark or over F mark on dipstick Oil Sentry Some engines are equipped with optional Oil Sentry oil pressure monitor Oil Sentry will either stop the engine or activate a low oil waming light if the oil pressure gets low Actual Oil Sentry use will vary depending on the engine application NOTE Oil Sentry is not a substitute for checking oil level BEFORE EACH USE Make sure the oil level is maintained up to the F mark on dipstick CHANGE OIL For a new engine change oil after the first 5 hours of operation Thereafter change oil as specified in the Oil Change Intervals table For an overhauled engine or those rebullt with a new short block use straight 30 weight Service Class SF or SG oil for the first 5 hours of operation Change the oil after this initial run in period Thereaf ter change the oil as specified in the Oil Change In tervals table Drain oil while the engine is still warm from operation The oil will flow
110. leaner li 3 Remove the base screws air cleaner base breather hose and gasket Gasket Reassembly 1 Install the gasket air cleaner base breather hose J and base screws Intake Elbow NOTE Make sure breather hose seals tightly in air cleaner base and breather cover to prevent unfiltered air from entering engine 2 Install the paper element precleaner cleaned and oiled element cover and element cover seal 3 Install the air cleaner cover and wing nut Tighten wing nut 1 2 to 1 full tum after nut contacts cover Do not overtighten Figure 5 3 Dome Air Cleaner Assembly ANTI ICING Refer To Figure 5 4 The anti icing air cleaner assembly uses heat from the exhaust manifold to prevent ice buildup in the carbure tor and intake manifold during cold weather operation 5 2 SECTION 5 AIR CLEANER Air Cleaner SS Aa Cover A Element Cover Seal a Element Cover Bn Optional VP TUS Precleaner 4 Heater i Heater dT SS Cover Paper Element Base Seal DOS er m d Base Screws 4 Air Cleaner 1 E oui Base a Breather Hose On The Application Figure 5 4 Anti Icing Air Cleaner Assembly Disassembly 1 Remove the wing nut and air cleaner cover 2 Remove the element cover seal element cover paper element precleaner and air cleaner base seal 3 Remove the base screws air cleaner base
111. lectric starter drives The use of other lubricants can cause the drive to stick or bind 5 Apply a small amount of Loctite No 271 to stop nutthreads Assemble drive parts in reverse order of removal Torque stop nut to 160 in Ib 6 Reinstall starter to crankcase CLEAN CYLINDER HEADS AND COMBUSTION CHAMBERS Every 500 operating hours 250 hours when leaded gasoline is used remove cylinder heads and clean combustion chambers Refer to Figure 3 9 Wooden Or Plastic Scraper Cylinder udo c Figure 3 9 Cleaning Cylinder Heads and Combustion Chambers 1 Remove cylinder head baffles and cylinder heads 3 6 2 Clean away combustion deposits using a wooden or plastic scraper 3 Reinstall cylinder heads using new gaskets Torque cylinder head fasteners in increments to 15 20 ft Ib in the sequence specified in Figure 3 10 Figure 3 10 Cylinder Head Fastener Tightening Sequence CHECK VALVE TO TAPPET CLEARANCE Every 500 operating hours remove breather valve cov ers and check valve to tappet clearance with a flat feeler gauge Refer to Figure 3 11 The engine must be cold when checking this clearance ro Feeler Valve Movement 7 Gauge Is Observed Check Clearance Of This Side Figure 3 11 Measuring Valve To Tappet Clearance Remove Air Cleaner Valve Covers Breather And Spark Plugs 1 Disassemble air cleaner Disconnect breather tube from air cleaner base R
112. lenoid 2 Install the panel with key switch and seif tapping screws Install the kill lead to connector Install the connector to back of key switch Refer to Figure 11 44 11 15 SECTION 11 REASSEMBLY Keyswitch Kill Lead Connector Self Tapping Screw Engine Mounted Throttle And Choke Controis Round Head Pan Head Screws Intake Manifold Figure 11 44 Installing Key Switch 3 Install the rectifier regulator and hex cap screws Install the lead to center position of connector Install the connector to rectifier regulator Refer to Figure 11 45 Figure 11 45 Install Rectifler Regulator INSTALL CARBURETOR AND INTAKE MANIFOLD 1 Install the gasket intake elbow plain washer round head screw intemal tooth lock washers and pan head screws to carburetor Refer to Figure 11 46 11 16 Figure 11 46 Installing Carburetor to Intake Manifold 2 Install the gasket carburetor with intake elbow and hex nuts to intake manifold Torque hex nuts to 150 In Ib 3 Install the engine mounted throttle and choke con trols if so equipped 4 Install the gaskets intake manifold with carburetor lifting straps split lock washers and hex cap screws Torque screws to 150 In Ib Refer to Figure 11 47 Hex Cap Screws And Lock Washers Lifting Strap Carburetor Lifting Strap intake Hex Cap Screws Manitold And Lock Washers Figure 11 47 In
113. llow the cleaner manufac turer s warnings and instructions on its proper and safe use Never use gasoline as a cleaning agent 64 5 SECTION 6A FUEL SYSTEMS AND GOVERNORS All parts should be carefully cleaned using a carbure tor cleaner such as acetone Be sure all gum depos its are removed from the following areas Carburetor body and bore especially the areas where throttle plate choke plate and shafts are seated Float and float hinge Fuel bowl e Idle fuel and off idle ports carburetor bore ports In main fuel adjusting needle and main fuel seat Note these areas can be cleaned using piece of fine wire in addition to cleaners Be careful not to enlarge the ports or break the cleaning wire within ports Blow out all passages with compressed air NOTE Do not submerge carburetor in cleaner or sol vent when fiber and rubber seals are installed The cleaner may damage these seals Inspection Carefully inspect all components and replace those that are worn or damaged Inspect the carburetor body for cracks holes and other wear or damage Inspect the float for dents or holes Check the float hinge tor wear and missing or damaged float tabs Inspect the intet needle and seat for wear or grooves Inspect the tips of the main fuel and idle fuel ad justing needles for wear or grooves Inspect the throttle and choke shaft and plate as semblies for wear or excessive play CARBU
114. ly with foam dust seal from carburetor body 6B 6 SECTION 6B FUEL SYSTEMS Choke Shaft Removal 1 Because the edges of choke plate are beveled mark the choke plate and carburetor body with a marking pen to ensure correct reassembly refer to Figure 6B 8 Also take note of the choke plate position in bore and the position of the choke lever Choke Plate Marking Pen Carburetor Body Figure 6B 8 Marking Choke Plate and Carburetor Body 2 Carefully and slowly remove the screws securing the choke plate to choke shaft Remove the choke plate 3 File off any burrs which may have been left on the choke shaft when the screws were removed Do this before removing the choke shaft from carbu retor body 4 Rotate the choke shaft until the cutout portion of shatt is facing the air cleaner mounting surface refer to Figure 6B 9 Place the carburetor body on workbench with choke side down Remove the choke lever shaft assembly from carburetor body the detent ball and spring will drop out Air Cleaner Mounting Surface Choke Lever Shaft Assembly Cutout Portion Ot Choke Shaft Figure 6B 9 Removing Choke Lever Shaft Cleaning A WARNING Flammable Solvents Carburetor cleaners and Solvents are extremely flammable Keep sparks flames and other sources of ignition away from the area Follow the cleaner manufacturer s warnings and instructions on its proper and safe use Never use gas
115. m cold cranking amps is normally used Refer to the equip ment manufacturer s instructions for specific information Battery Test if the battery charge is not sufficient to crank the en gine recharge the battery NOTE Do not attempt to jump start the engine with another battery Starting the engine with bat teries larger than those recommended can burn out the starter motor Test the battery voltage by connecting DC voltmeter across the battery terrninals crank the engine If the battery drops below 9 volts while cranking the battery is discharged or faulty Refer to Figure 8 14 DC Voltmeter Figure 8 14 Checking Battery Voltage SECTION 8 ELECTRICAL SYSTEM AND COMPONENTS Battery Charging WARNING Dangerous Acid Explosive Gases Batteries contain sulfuric acid To prevent acid burns avoid contact with skin eyes and clothing Batteries produce explosive hydrogen gas while be ing charged Charge the battery in well ventilated areas Keep cigarettes sparks open flame and other sources of ignition away from battery at all times To prevent accidental shorting and the resulting sparks remove jewelry when servicing the battery When disconnecting battery cables always disc nect the negative ground cable first When on connecting battery cables always connect the neg ative cable last Before disconnecting the negative ground cable make sure all switche
116. m crankshaft Refer to Figure 9 35 3 Remove the retaining ring plain washers and cross shaft Hex Nuts _ Retaining Ring Plain Washer Connecting Rods Figure 9 35 Removing Connecting Rods REMOVE GOVERNOR Figure 9 37 Removing Governor Gear GEAR AND CROSS SHAFT REMOVE OIL PICKUP AND OIL PUMP 1 Remove the governor stop pin and copper washer te Refer to Figure 9 36 Oil Pickup 1 Remove the spring clip using a long nosed pliers Remove the oil pickup housing Refer to Figure 9 38 Oit Pickup Tube Clamp Dipstick Tube Housing Figure 9 38 Removing Oil Pickup Components Figure 9 36 Removing Governor Stop Pin 2 s P 2 Remove the self tapping screw clamp and oil pickup tube 9 11 SECTION 9 DISASSEMBLY Oil Pump NOTE The oil pump rotors shaft and drive gear are virtually trouble free and normally require little service These parts should be removed only if service or replacement is necessary 1 Remove the self tapping screws cover and pump rotors Refer to Figures 9 39 and 9 40 Screws Figure 9 40 Removing Oil Pump Rotors 2 Using a small diameter drift punch drive the roll pin out of the pump drive gear and shaft Remove shaft drive gear and shim spacer Refer to Figure 9 41 Oii Pump Cover Figure 9 39 Removing Pump Cover Figure 9 41 Removing Pump Drive Gear 9 12 M18 amp M
117. m engine parts When such a cleaner is used follow the manufacturer s instructions carefully Make sure all traces of the cleaner are re moved before the engine is reassembled and placed in operation even small amounts of these cleaners quickly break down the lubricating properties of en gine oil TYPICAL DISASSEMBLY SEQUENCE Disconnect spark plug leads Drain oil and remove oil filter Remove mufflers and exhaust elbows Remove air cleaner Remove intake manifold and carburetor Disconnect wiring remove rectifier regulator key switch and solenoid 7 Remove top baffle cylinder head baffles and blower housing 8 Remove breather and valve cover 9 Remove fuel pump 10 Remove ignition module and bracket 11 Remove grass screen flywheel and fan 12 Remove electric starter 13 Remove stator 14 Identify engine sides 15 Remove spark plugs and cylinder heads 16 Remove cylinder barrels 17 Remove valves 18 Remove pistons from connecting rods 19 Remove piston rings 20 Remove closure plate oil pressure relief valve and rear oil seal 21 Remove oil filter adapter 22 Split the crankcase 23 Remove camshaft and tappets 24 Remove crankshaft front oil seal and bearings 25 Remove connecting rods 26 Remove govemor gear and cross shaft 27 Remove oil pickup and oil pump DISCONNECT SPARK PLUG LEADS DRAIN OIL AND REMOVE OIL FILTER 1 Remove the oil fill cap d
118. mmeter Switch Shutdown Rectifier Regulator AC Leads Figure 8 12 25 amp Stator and Rectifler Regulator 25 Amp Stator 8 8 SECTION 8 ELECTRICAL SYSTEM AND COMPONENTS Troubleshooting Guide 15 25 amp Battery Charging Systems NOTE Zero ohmmeters on each scale to ensure accurate readings Voltage tests should be made with engine running at 3600 RPM no load Battery must be fully charged Problem Test Conclusion 1 Trace B lead from rectifier regulator to key switch or other accessible connection Discon nect it from switch or connection Connect an ammeter from loose end of B lead to positive terminal of battery Connect DC voltmeter from loose end of B lead to negative terminal of battery With engine running at 3600 RPM read voltage on voltmeter If voltage Is 13 8 volts or more place a mini mum load of 5 amps on battery to reduce volt age Observe ammeter NOTE Turn on lights if 60 watts or more Or place a 2 5 chm 100 watt resistor 1 If voltage is 13 8 14 7 and charge rate in creases when load is applied the charging sys tem is OK and battery was fully charged If voltage is less than 13 8 or charge rate does not increase when load is applied test stator Tests 2 and 3 N If voltage is 28 volts or more stator is OK Rec tifier regulator is faulty Replace the rectifier regulator If voltage is less than 28 volts stato
119. more freely and carry away more im purities Change oil as follows 1 Remove the oil drain plug and dipstick Refer to Figure 3 2 Tilt the engine slightly towards the drain hole to obtain better drainage Figure 3 2 Oil Drain Plug Location OIL CHANGE INTERVALS Temperature Oll Type Engine Type Interval ABOVE With Filter 50 Hours 32 F 0 C SAE 30 Without Filter 25 Hours BELOW With Filter 50 Hours 32 F 0 C Multiviscosity Without Filter 25 Hours 25 hours for continuous and or heavy duty operation 3 2 2 Reinstail the drain plug Make sure it is tightened securely 3 Fill with new oil of the proper type to the F mark on the dipstick Always check the level on dip stick before adding more oil Make sure the en gine is level when filling and checking oil CHANGE OIL FILTER Figure 3 3 Oil Filter Change the oil filter every other oil change in accor dance with the Oil Change Intervals table Always use a genuine Kohler oil filter and change as follows Drain crankcase oil then remove old filter 2 Before installing replacement filter apply a thin coating of oil on surface of the rubber seal 3 Tum filter clockwise until rubber seal contacts the filter adapter then tighten the filter an additional tum 4 Add an additional 1 2 pint of oil for the filter capacity 5 Start the engine and check for and correct any cil leaks SERVI
120. n Set idle speed to 1200 RPM or 75 RPM by turning the idle speed adjust ing screw in or out NOTE The actual idle speed depends on the application Refer to the equipment man ufacturer s instructions for specitic idle speed settings Disassembly Refer to Figure 6A 7 1 Remove the bowl retaining screw retaining screw gasket and fuel bowl 2 Remove the float pin float fuel inlet needle baffle gasket and bowl gasket 3 Remove the fuel inlet seat and inlet seat gasket Remove the idle fuel and main fuel adjusting needles and springs Remove the idle speed ad justing screw and spring 4 Further disassembly to remove the throtlle and choke shafts is recommended only if these parts are to be replaced Refer to Throttle And Choke Shaft Replacement SECTION 6A FUEL SYSTEMS AND GOVERNORS Main Fuel d Needle Gasket Idle Speed Screw Spring Spring Bl Carburetor 2 Body by TT Idle Fuel Ses Bowl Needle Fai d Gasket Fuel Inlet z Seat 0 Baffle Gasket 8 s m Seat x Fuel Inlet Sy Needle X Float Pin Float Hinge Fuel Bowl S 2 retaining Retaining Screw Screw Gasket Figure 6A 7 Kohier Built Adjustable Jet Carburetor Exploded View Cleaning A WARNING Flammable Solvents Carburetor cleaners and solvents are extremely flam mable Keep sparks flames and other sources of ignition away from area Fo
121. nded an incorrect type or weight of oil was used over rich carburetor set tings and weak ignition to name a few CLEANING THE ENGINE After inspecting the extemal condition of the engine clean it thoroughly before disassembling Also clean individua components as the engine is disassembled Only clean parts can be accurately inspected and gauged for wear or damage There are many comrnercially available cleaners that Quickly remove grease oil and grime from engine parts When such a cleaner is used follow the manu facturer s instructions carefully Make sure all traces of the cleaner are removed before the engine is reas sembled and placed into operation Even small amounts of these cleaners quickly break down the lubricating properties of engine oil 4 2 SECTION 4 TROUBLESHOOTING Insert the stopper hose into the oil fill hole Leave the other vent of manometer open to BASIC ENGINE TESTS Crankcase Vacuum Test atmosphere Make sure the shut off clamp is A partial vacuum should be present in the crankcase closed when the engine is operating at normal temperatures 2 Start the engine and run at high speed 3200 to Pressure in the crankcase usually caused by a 3600 RPM clogged or improperly assembled breather can cause oil to be forced out at oil seals gaskets or other available spots 3 Open the clamp and note the water level in the tube The level in the engine side should be 13 to 20 in abo
122. ned and reused if the face and margin are in good shape Ifa Note the warped head margin damaged and too narrow These valve is worn to where the margin is less than 1 32 do not reuse it conditions could be attributed to excessive hours or a combination The valve shown was in operation for almost 1000 hours under poor operating conditions controlled test conditions 10 5 SECTION 10 INSPECTION AND RECONDITIONING Leakage A poor grind on face or seat of valve will allow leakage resulting in a burned valve on one side only Coking Coking is normal on intake valves and is not harmful the seat is good the valve could be reused atter cleaning Excessive Combustion Temperatures The white deposits seen here indicate very high combustion temperatures usually due to a lean fue mixture Gum Gum deposits usually result from using stale gasoline This condition is often noted in applications where fuel is not drained out of tank during the off season Gum is a prevalent cause of valve sticking The cure is to ream the valve guides and clean or replace the valves depending on their condition Stem Corrosion Moisture in fuel or from condensation are the most common causes of valve stem corrosion Condensation oc curs from improper preservation during storage and when engine is repeatedly stopped before it has a chance to reach normal oper ating temperatures Replace corr
123. ng factors Faulty electric starter starter solenoid Engine Cranks But Witt Not Start Seized intemal engine components 1 Empty fuel tank 2 Fuel shutoff valve closed Engine Runs But Misses 3 Clogged fuel line 1 Dirt or water in fuel system 4 Spark plug leads disconnected 2 Spark plug leads loose 5 Key switch or kill switch in off position 3 Loose wires or connections which intermittently 6 Faulty spark plugs short kill terminal of ignition module to ground 7 Faulty ignition module 4 Carburetor improperly adjusted 8 Dirt or water in the fuel system 5 Engine overheating Engine Starts But Does Not Keep Running 6 Incorrect valve to tappet clearance 1 Restricted fuel tank vent 7 Faulty ignition module 2 Dirt or water in fuel system 3 Faulty choke or throttle controts cables Engine Will Not Idle 4 Loose wires or connections which short 1 idle speed adjusting screw improperly set kill terminal of ignition module to ground 2 Dirt or water in fuel system 5 Carburetor improperly adjusted 3 Idle fuel adjusting screw improperly set 6 Faulty cylinder head gaskets 4 Restricted fuel tank vent 7 Faulty fuel pump 5 Faulty spark plugs Engine Starts Hard 6 Incorrect valve to tappet clearance 1 Hydrostatic transmission is not in neutral PTO 7 Low compression 8 Stale fuel and or gum in carburetor drive is engaged 2 Loose wires or connections 3 Dirt or water in fuel system Engine Overheats
124. ng procedures FUEL RECOMMENDATIONS A WARNING Explosive Fuels Gasoline Is extremely flammable and its vapors can explode if ignited Store gasoline only in ap proved containers in well ventilated unoccupied buildings away from sparks or flames Do not fill fuel tank while the engine is hot or running since Spilled fuel could ignite if it comes in contact with hot parts or sparks from ignition Do not start en gine near spilled fuel wipe up spills immediately Never use gasoline as a cleaning agent General Recommendations Purchase gasoline in small quantities and store in clean approved containers A container with a ca pacity of 2 gallons or less with a pouring spout is rec ommended Such a container is easier to handle and helps eliminate spillage during refueling Do not overfill the fuel tank Leave room for the fuel to expand Do not use gasoline left over from the previous sea son to minimize gum deposits in your fuel system and to insure easy starting Do not add oil to the gasoline Fuel Type For best results use only clean fresh unleaded gaso line with a pump sticker octane rating of 87 or higher In countries using the Research method it should be 90 octane minimum Unleaded gasoline is recommended as it leaves less combustion chamber deposits Leaded gasoline may be used in areas where unleaded is not available and exhaust emissions are not regulated Be aware how ever that the cylinder head
125. not covered by the engine warranty A logo or symbol on oil containers identifies the API service class and SAE viscosity grade Rod Check Oil Level Check oil level BEFORE EACH USE NOTE Do not operate the engine with the oil level below 2 mark or over F mark on dipstick Operating Range Change Oil For a new engine change oil after the first 5 hours of operation Thereafter change the oil as specified in the following Oil Change Intervals table For an overhauled engine or those rebuilt with a new short block use straight 30 weight Service Class SF or SG oil for the first 5 hours of operation Change the oil after this initial run in period Refill with Service Class SF or SG oil as specified in the table OIL CHANGE INTERVALS Temperature Oll Type Engine Type Interval ABOVE With Filter 50 Hours 32 F 0 C SAE 30 Without Filter 25 Hours BELOW With Filter 50 Hours 32 F 0 Multiviscosity Without Filter 25 Hours 25 hours for continuous and or heavy duty operation 1 4 SECTION 1 SAFETY AND GENERAL INFORMATION Oil Filter Some engines are equipped with an oil filter Replace the oil filter every other oil change in accordance with the Oil Change Intervals table Always use a genu ine Kohler replacement oil filter Refer to the Periodic Maintenance Section for de tailed oil checking and changi
126. oblem Automatic Choke Service Guide Causes Faulty lead to choke Faulty iead to ground Figure 6A 22 Automatic Choke 1 Check for secure lead connections 2 Check for secure lead connections Solutions Make continually check on lead Replace if no continuity Choke Won t Close 2 Make continuity check on lead When Cranking Replace if no continuity 1 Poor adjustment 1 Adjust choke 2 Choke shaft binds vamish 2 Repair with kit or replace choke 3 Wash with carburetor cleaner Choke Will Not Fully Open 1 Poor adjustment 1 Adjust choke 2 Fautty choke 2 Repair with kit or replace choke 6A 16 SECTION 6A FUEL SYSTEMS AND GOVERNORS Power Lead Ground Solenoid Plunger Shutdown Control Solenoid Retaining Bracket Choke Heater Automatic Choke Figure 6A 23 Engine Shutdown Control and Automatic Choke Automatic Choke Inspection 1 Disconnect the high tension leads from spark plugs so the engine will not start 2 Remove the air cleaner cover element and base 3 Tum the start switch to the start position and hold for five seconds The choke should fully close and release when the start switch is released 4 If he choke does not function properly Step 3 see Service Guide on previous page Automatic Choke Service Choke Unit Replacement see Flgure 6A 23 1 Position the choke unit on the two mounting screws so
127. oded valves Overheating An exhaust valve subject to overheating will have a dark discoloration in the area above the valve guide Wom guides and faulty valve springs may cause this condition Also check for clogged air intake blocked fins and lean fuel mixture when this condition is noted SECTION 10 INSPECTION AND RECONDITIONING Valve Guides If a valve guide is wom beyond specifications it will not guide the valve in a straight line This may result in burnt valve faces or seats loss of compression and excessive oil consumption To check valve guide to valve stem clearance thor oughly clean the valve guide and using a split ball gauge measure the inside diameter Then using an outside micrometer measure the diameter of the valve stem at several points on the stem where it moves in the valve guide Use the largest stem diameter to cal culate the clearance If the clearance exceeds 005 on intake or 007 on exhaust valve determine wheth er the valve stem or the guide Is responsible for the excessive clearance If the valve stem diameter is within specifications then replace the valve guide Remove Valve Gulde The valve guides are a tight press fit in the cylinder barrel A valve guide removal tool is recommended to remove the guides refer to Section 2 Special Tools To remove valve guide refer to Figure 10 6 and proceed as follows Adapter Cylinder Stud 5 16 x 2 1
128. ol Test Refer to Figure 6A 23 for identification of parts 1 Remove shutdown control solenoid and plunger from carburetor body by loosening the screw so the retaining bracket holding the control can be shifted Do not disconnect the lead wires 2 Pull the shutdown control out of the carburetor 3 Hold the plunger approximately 1 4 away from the Turn the ignition switch to ON and reiease the plunger 6A 17 SECTION 6A FUEL SYSTEMS AND GOVERNORS If the plunger is drawn into the solenoid the shut down control is functioning properly If the plunger is not drawn into the solenoid the solenoid is faulty and must be replaced As a temporary fix until a replacement solenoid can be obtained the plunger can be removed from the shutdown control and the solenoid reinstalled minus the plunger After replacing solenoid refer to Section 6A for carbu retor adjustment The removal of the plunger will not affect normal car buretor function however to prevent unfiltered air from entering the carburetor the defective solenaid must be reinstalled over shutdown control vent hole after the plunger has been removed ENGINES EQUIPPED FOR DUAL FUEL Hard starting and low power on units equipped for dual fuel gasoline LPG have been traced to two causes 1 Improper size venturi 2 Improper adjustments to regulator and adapter The following changes and or adjustments must be made to the unit to assure pr
129. oline as a cleaning agent All parts should be carefully cleaned using a carbure tor cleaner such as acetone Be sure all gum depos its are removed from the following areas Carburetor body and bore especially the areas where the throttle plate choke plate and shafts are seated Idle fuel and off Idle ports in carburetor bore main Jet bowl vent and fuel Inlet seat NOTE These areas can be cleaned using a piece of fine wire in addition to cleaners Be careful not to enlarge the ports or break the cleaning wire within ports Blow out all passages with compressed air Float and float hinge e Fuel Bowl e Throttle plate choke plate throttle shaft and choke shaft NOTE Do not submerge the carburetor in cleaner or solvents when fiber rubber or foam seals or gaskets or the fuel inlet needle are installed The cleaner may damage these parts 6B 7 SECTION 6B FUEL SYSTEMS Inspection Carefully inspect all components and replace those that are worn or damaged Inspect the carburetor body for cracks holes and other wear or damage Inspect the float for cracks or holes Check the float hinge for wear and missing or damaged float tabs Inspect the fuel inlet needle for wear or grooves Inspect the tip of the idle fuel adjusting needle for wear or grooves Inspect the throttle and choke shaft and plate as semblies for wear or excessive play Repair Always use new
130. on plate should face the air cleaner mounting surface and be upright Apply Loctite 609 to threads of 2 plate retaining screws Install the screws so they are slightly loose 4 Operate the choke lever check for binding be tween the choke plate and carburetor bore Ad just plate as necessary then torque screws to 8 12 in Ib SECTION 6B FUEL SYSTEMS Carburetor Reassembly 1 If the welch plugs have been removed for ing new welch plugs must be installed Use tool No KO1017 and the following procedure to install the welch plugs a Position the carburetor body securely with the welch plug cavities to the top b Place a new welch plug into the cavity with the raised portion up Use the end of the tool that is about the same size as plug and flat ten the plug Do not force the plug below the top surface Refer to Figure 6B 12 Tool KO1017 Carburetor Body New Welch Plug Figure 6B 12 Installing Welch Plugs c After welch plugs are installed seal the ex posed surface with Glyptal or an equivalent sealant Allow the sealant to dry NOTE If a commercial sealant is not available fingemail polish can be used 2 Install the main fuel jet and torque to 12 16 in Ib 3 Install fuel inlet needle clip assembly attach clip to the adjusting tab on float as shown in Figure 6B 13 slowly lower float into position in seat 4 Set Float Level Invert the carburetor so the float tab r
131. oper performance NOTE When switching from gasoline to LPG make sure that gasoline supply has been tuned off and that all gasoline is vacated from the float bow and fuel lines by running the engine out of gasoline 1 Check venturi size of adapter a If adapter is equipped with no 26 size venturi move on to adjustment procedure b If the adapter is equipped with a no 20 size venturi see Figure 6A 24 remove no 20 venturi and replace with no 26 size venturi 64 18 Load Screw Adaptor Venturi Venturi Size Last 2 digits Reference only Figure 6A 24 Venturi Identification 2 Check and make adjustments to regulator and adapter a Before starting engine set the mixture load screw at the adapter 1 1 2 tums out from closed b If engine is equipped with Century brand regu lator vaporizer no idle adjustment is neces sary Move to Step C If equipped with Beam model 50 or 50 secondary regulator proceed as follows Start engine with engine running manually hold throttle against idle stop screw Confirm that engine is running at or below 1500 RPM with tachometer Tum the idle mixture screw located on sec ondary regulator IN toward the rich side until RPM drops This should be confirmed with a tachometer Then turn screw OUT toward the lean side until engine RPM recovers and again begins to fall off At this point again turn the screw IN just until the engine reac
132. ound pistons Refer to Figure 11 28 Piston Ring Compressor Installed Around Piston Cylinder Barrel Figure 11 28 Installing Pistons 3 Orient the Fly mark on pistons so it points to wards flywheel intake port side of cylinder bar rels Refer to Figure 11 29 Top of Piston Arrow Must Point Towards Flywheel Figure 11 29 Piston Installation Direction Identifier Gently push the pistons into cylinder bores from cylinder head side do not pound on piston Re ferto Figure 11 28 Make sure that used pistons are reinstalled into the proper cylinder barrels as marked during disassembly 4 Continue pushing the piston into bore until the pis 1on pin bore is completely exposed on the crank case side of cylinder barrel Make sure the oil control ring is not exposed INSTALL CYLINDER BARRELS 1 Make sure the mating surfaces of crankcase and cylinder barrels are cleaned and prepared as di tected by the sealant manufacturer Refer to INSTALL CAMSHAFT BORE PLUG AND SEAL CRANKCASE 2 Apply a 1 16 bead of sealant to the crankcase as shown in Figure 11 30 Follow the sealant man ufacturer s recommendations regarding setting 11 10 SECTION 11 REASSEMBLY Figure 11 30 Cylinder Barrel Sealant Pattern Cylinder Barrel Fastener Torque Sequence 3 Install one 1 new piston pin retainer in one side of each piston pin bore 4 Install the pistons inside cylinder barrels piston
133. ove the engine spark plugs b Check wires and terminais of ignition mod ENGINE ule and other components for accidental NOT b Make sure the engine ignition switch kill grounding and or damaged insulation START Switch and or key switch are in the run Position c Crank the engine and observe the test plugs Visible and audible sparks should be produced If wires and terminals are OK the ignition module is probably faulty and should be replaced Test module further using an ohmmeter Test 4 4 Measure the secondary resistance of module using an ohmmeter Refer to Figures 8 1 and 8 4 NOTE Module must have been fixed to per form Test 4 Secondary Secondary Leads Terminals Resistance C D 22 000 42 000 ohms If resistance is within range module secondary is OK If resistance is low or 0 ohms module second ary is shorted Replace module resistance is high or infinity ohms module secondary is open Replace module 8 2 SECTION 8 ELECTRICAL SYSTEM AND COMPONENTS Ignition Module REMOVAL 1 Remove the blower housing 2 Remove the kill lead from kill terminal of module Refer to Figure 8 5 1 Cylinder arret Figure 8 5 Removing Ignition Module 3 Remove the hex flange screws and module from bracket on 1 cylinder barrel INSTALLATION 1 Install the module and hex flange screws to bracket Move the module as far from Figure 8 3
134. pins and new piston pin retainers to connecting rods Refer to Figure 11 31 Cylinder Connecting Rod Barrel Piston Piston Pin And Retainers Figure 11 31 Installing Pistons Cylinder Barrels to Connecting Rod NOTE To prevent damage to the connecting rods when reinstalling the cylinder barrels make sure the barrels and connecting rods are supported at all times Do not allow the connecting rods to drop against the edges of crankcase 5 Slide the cylinder barrels over pistons and crank case studs 6 Install the plain washers and hex nuts Torque hex nuts 1 and 2 to 100 In Ib Torque the re maining hex nuts to 100 in Ib in the most expe dient sequence Refer to Figure 11 30 7 Torque all hex nuts to 200 Ib in the sequence shown MEASURE VALVE TO TAPPET CLEARANCE IMPORTANT The piston must be at top dead center TDC of the compression stroke to measure valve to tappet clear ance By rotating the crankshaft and observing the tappets for movement it can be determined If a cylin der is at TDC for example the crankshaft is rotated and movement is observed in the 42 side valve box the opposite cylinder 1 side will be at TDC and valve to tappet clearance can be measured Rotating the flywheel one complete revolution 360 will then cause movement in the 1 side valve box The 2 side cylinder will be at TDC enabling mea surement of valve to tappet clearance for that sid
135. press Ball And Spring Choke Shaft Figure 6A 12 Installing Choke Shaft 3 Install choke plate to choke shaft Make sure marks are aligned and plate is positioned properly in bore Apply Loctite to threads of 2 3 48 x 7 32 screws Install screws so they are Slightly loose 4 Operate choke lever Check for binding between choke plate and carburetor bore Loosen screws and adjust piate as necessary then tighten screws securely Install Throttle Shaft And Throttle Plate 1 Install throttle shaft into carburetor with cutout por tion of shaft facing out 2 Install throttle plate to throttle shaft Make sure marks are aligned and plate is positioned properly bore Apply Loctite to threads of 2 43 48 x 7 32 screws install screws so they are Slightly loose 3 Apply finger pressure to throttle shaft to keep it firmly seated against pivot in carburetor body Rotate the throttle shaft until throttle plate fully closes the bore around its entire perimeter then tighten screws 6A 10 SECTION 6A FUEL SYSTEMS AND GOVERNORS 4 Operate the throttle lever and check for binding between the throttle plate and carburetor bare Loosen screws and adjust plate as necessary then tighten screws securely Reassemble Carburetor Refer to the following Reassembly portion of this section Reassembly 1 install the fuel inlet seat gasket and fuel inlet seat into carburetor body Torque seat to 35 45 In
136. r and armature be careful not to lose the thrust washer and be sure to reinstall it later Front collars Snap rings Rear collars Rear collar remains Front collar remains Figure 8 25 Removing the Stop Collar 2 Using the SST tool for removing the GA stop collar remove the stop collar as shown in Figure 8 24 insert ihe blade of the SST into the groove between the two adjacent stop collars and then remove the stop collar while widening the groove SECTION 8 ELECTRICAL SYSTEM AND COMPONENTS NOTE Since the rear stop collar may engage with the snap ring if the shaft s end is hit too hard be sure to hit it with the proper force i hammer Box wrench Rear stop collar Figure 8 26 Removing the Rear Stop Collar lene hammer Align notches of removed rear collar with protrusions of front collar Hold pinion against rear collar Figure 8 27 Removing the Front Stop Collar 9 After the stop collars are removed the retainer can be removed from the armature shaft Do not reuse the retainer Figure 8 28 Replacement Brush BRUSH REPLACEMENT The brushes in the starter are part of the starter frame brush kit Part No 52 221 01 contains four replacement brushes and springs If replacement is necessary all four brushes should be replaced 1 Remove brushes from brush holder and remove brush holder from frame Trim off Brush lead wi
137. r is probably faulty and should be replaced Test stator fur ther using an ohmrneter Test 3 3a If resistance is 064 0 2 ohms the stator is OK If resistance is infinity ohms stator is open Re place stator 3b if resistance is infinity ohms no continuity the stator is OK not shorted to ground If resistance or continuity is measured the sta tor leads are shorted to ground Replace stator across battery terminals NO 2 Remove connector from rectifier regulator CHARGE With engine running at 3600 RPM measure AC voltage across stator leads using an AC BATTERY voltmeter 3a With engine stopped measure the resistance across stator leads using an ohmmeter 3b With engine stopped measure the resistance from each stator lead to ground using an ohmmeter 1 Perform same test as Step 1 above BATTERY CONTINUOUSLY CHARGES AT HIGH RATE If voltage is 14 7 volts or less the charging sys tem is OK The battery is unabie to hold charge Service battery or replace as necessary If voltage is more than 14 7 volts the rectifier regulator is faulty Replace rectifier regulator 8 9 SECTION 8 ELECTRICAL SYSTEM AND COMPONENTS 8 10 D C Voltmeter Rectifier Regulator Ammeter Battery Figure 8 13 Connections for Testing 15 and 25 Systems BATTERY Batteries are supplied by the equipment manufacturer A 12 voit battery with a rating of 250 minimu
138. r seal s Make sure element is sealed tightly against the element cover and air cleaner base 5 Install the air cleaner cover and wing nuts Tight en wing nuts 1 2 to 1 full turn after nuts contact cover Do not overtighten Inspect Air Cleaner Components Whenever the air cleaner cover is removed or servic ing the element or precleaner check the following components Air Cleaner Base Make sue it seals tightly against intake elbow and is not bent or damaged Element Cover and Element Cover Seals Make sure element cover is not bent or damaged Make sure element cover seals are in place to ensure element is sealed tightly between element Cover and air cleaner base Breather Tube Make sure it is sealed tightly in air cleaner base and breather cover NOTE Damaged worn or loose air cleaner com ponents could allow unfiltered air into the engine causing premature wear and fail ure Replace all damaged or worn components 5 4 M18 amp M20 SECTION 6A FUEL SYSTEMS AND GOVERNORS FUEL SYSTEM The typical fuel system and related components in clude the fuel tank with vented cap in line fuel filter fuel pump carburetor and interconnecting fuel line Refer to Figure 6A 1 Kohler built carburetors are dis cussed in this section plus Dual Fuel System Walbro Carburetors are covered in Section 6B Operation The fuel from the tank is moved through the in line filter and fuel tines by the fuel p
139. re Figure 8 29 Cutting Brush Lead Wires from the Frame Posts 2 Cut the brush lead wire at the edge of the post with a pair of nippers 3 File off burrs on the post Remove burrs File Figure 8 30 Filing Off Burrs on Posts 4 Place the plate of the spare brush on the welded partion of the brush lead wire and then crimp them together with a pair of pliers Be sure to align the edge of the lead wire 8 18 SECTION 8 ELECTRICAL SYSTEM AND COMPONENTS Plate A 5 Solder the crimped portion to the post 6 Replace the brush holder in the frame and place the brushes in the brush holder Reinstall the springs Trimmed edge Spare brush Crimp Figure 8 31 Connecting Replacement Brushes Solder Soldering iron Figure 8 33 Installing Snap Ring Starter Service Clean drive lever and armature shaft then apply Kohler electric starter drive lubricant or equivalent to lever and shaft Starter Reassembly EH 1 Insert the rear stop collar on the armature shaft Figure 8 32 Soldering Brush Cllps to Posts Always use new snap ring 8 19 SECTION 8 ELECTRICAL SYSTEM AND COMPONENTS Grease Grease Grease Thrust washer Engine oil Figure 8 34 Lubrication Points Grease Engine oil Engine oil Stop collar Pliers Pliers Figure 8 35 Tightening the Snap Ring 2 Place the retainer in
140. results against the table below LEAKDOWN TEST RESULTS Air escaping from crankcase breather Air escaping from exhaust system Air escaping from carburetor Gauge reading in low green zone Gauge reading in moderate yellow zone Gauge reading in high red 20 Defective rings or wom cylinder walls Defective exhaust valve Defective intake valve Piston rings and cylinder in good condition erent dd Mese Engine is still usable but there is some wear present Customer should start planning for overhaul or replacement VERUS Vases Rings and or cylinder have considerable wear Engine should be reconditioned or replaced 4 5 M18 amp M20 SECTION 5 AIR CLEANER Magnum engines are equipped with a high density paper air cleaner element Some specifications are also equipped with an oiled foam which surrounds the paper element Refer to Figure 5 1 Element Cover Seals Air Cleaner Element Optional Precleaner Element Figure 5 1 Air Cleaner Components Three types of air cleaner assemblies are used on Model M18 and M20 engines square dome or anti icing Refer to the instructions for the specific type of air cleaner being serviced SQUARE Refer To Figure 5 2 Disassembly 1 Remove the wing nuts and air cleaner cover 2 Remove the element cover seals element cover paper element and precleaner
141. retor Figure 9 7 Removing Intake Manifold and Carburetor 5 Remove the engine mounted throttle and choke controls if so equipped 6 Remove the hex nuts carburetor with intake el bow and gasket from intake manifold Refer to Figure 9 8 Engine Mounted Throttle And Choke Controls Intake Elbow Gasket Hex Nuts Round Head Screw Pan Head Screws Carburetor Figure 9 8 Removing Carburetor From Intake Manifold 7 Remove the pan head screws int tooth lock washers round head screw plain washer intake elbow and gasket from carburetor 9 3 SECTION 9 DISASSEMBLY DISCONNECT WIRING REMOVE RECTIFIER REGULATOR KEY SWITCH AND SOLENOID 1 Remove the connector from rectifier regulator Remove the lead from center position of connec tor Remove the hex cap screws and rectifier regulator Refer to Figure 9 9 fou Blower Housing Hex Cap a Screws Miron 8 Rectifier Regulator R Figure 9 9 Removing Rectifler Regulator 2 Remove the connector trom key switch Remove kill lead from connector Remove the self tapping screws and panel with key switch Refer to Figure 9 10 Keyswitch ue Panel Connector Self Tapping Self Tapping Screw Screw Figure 9 10 Removing Key Switch 3 Disconnect the leads from starter solenoid Re move the wire tie self tapping screws solenoid with bracket and spacer Refer to Figure 9 11 9 4 Selt Tapping
142. rs and solvents are extremely flammable Keep Sparks flames and other sources of ignition away from the area Follow the cleaner manufacturer s warnings and instructions on its proper and safe use Never use gasol ne as a cleaning agent 1 2 A WARNING Carbon Monoxide Can cause severe nausea fainting or death Do not operate engine in closed confined area e Sulfuric Acid in batteries can cause severe injury or death Charge only in well ventilation Keep sources of ignition away Lethal Exhaust Gases Engine exhaust gases contain poisonous carbon monoxide Carbon monoxide is odorless colorless and can cause death if inhaled Avoid inhaling exhaust fumes and never run the engine in closed building or confined area A WARNING Spring Under Tension Retractable starters contain a powerful flat wire recoil spring that is under tension Do not remove the center screw from the starter until the spring tension is released Removing the center screw before releasing spring tension or improper starter disassembly can cause the sudden and potentially dangerous release of the spring Always wear safety goggles when servicing retractable starters full face protection is recommended To ensure personal safety and proper starter disassembly and reassembly follow the procedures In this section carefully Dangerous Acid Explosive Gases Batteries contain sulfuric acid To prevent acid
143. rtion Refer to your parts manual for correct kit part Spring free length should be approximately 992 number Replace spring if distorted or wen GOVERNOR GEAR v Crankcase End Inspection Inspect the governor gear teeth Look for any evi dence of wom chipped or cracked teeth If one or more of these problems is noted replace the governor gear Figure 10 20 Olt Pressure Rellef Valve 10 15 M18 amp M20 SECTION 11 REASSEMBLY The following sequence is suggested for complete engine reassembly This procedure assumes that all components are new or have been reconditioned and all component subassembly work has been com pleted This procedure may have to be varied slightly to accommodate options or special equipment Make sure old RTV sealant has been removed from compo nents using this before reassembling NOTE Make sure the engine is assembled using all specified torque values tightening se quences and clearances Failure to observe specifications could cause severe engine wear or damage NOTE Always use new gaskets NOTE Make sure all components have been cleaned BEFORE reassembly TYPICAL REASSEMBLY SEQUENCE Install oil pump and oil pickup Install cross shaft and governor gear Install connecting rods Install bearings and crankshaft Install tappets and camshaft install camshaft bore plug and seal crankcase Install front oil seal Instal
144. ructions are usually inctuded with new ring sets Follow instructions carefully Use a piston ring expander to install rings Install the bottom oil control ring first and the top compression ring last Refer to Figure 10 15 10 12 Oil Control Ring Three piece Piston Ring Dykem Siripe Piston Expander Figure 10 15 Piston Ring Installation Oil Control Ring Bottom Groove Install the ex pander and then the rails Make sure the ends of expander are not overlapped Compression Ring Center Groove Install the beveled ring using a piston ring installation tool Make sure the pip mark is up and the PINK dy kem stripe is to the left of end gap Compression Ring Top Groove install the top ting using a piston ring installation tool Make sure the pip mark is up and the BLUE dykem stripe is to the left of end gap SECTION 10 INSPECTION AND RECONDITIONING POSI LOCK CONNECTING RODS Posi Lock Connecting Rods are used in all Magnum M18 and M20 engines Because of the increase in piston pin boss thickness of the new style D pistons used the connecting rods on these engines have a narrower piston pin end than on older style Posi Lock connecting rods Therefore the Posi Lock connecting rods for the new pistons are not interchangeable with ihe Posi Lock connecting rods for the standard pis tons used on KT17 and 19 and KT17 and KT19 Series I engines Refer to Figure
145. rust applications use a roller thrust bearing and flat thrust washers on the flywheel end of the crankshaft Refer to Figure 11 14 Flywheel End Shaft Locating Washer Crankshaft Roller Sleeve Bearing Bearing Side Side Flat Thrust Washer Roller Thrust Bearing Sleeve Bearing Figure 11 14 Installing Roller Thrust Bearings SECTION 11 REASSEMBLY Install the 039 thrust washer roller thrust bearing 156 shaft locating washer and flanged sleeve bear ing to flywheel end of crankshaft INSTALL TAPPETS AND CAMSHAFT 1 Lubricate the stems of tappets with engine oil Install the tappets into crankcase sides Make sure that used tappets are reinstalled into the proper sides and positions intake or exhaust as marked during disassembly NOTE The intake valve tappet is closast to the flywheel side of crankcase The exhaust tappet is closest to the PTO side of crankcase 2 Put tape or governor spring around the tappet stems in the 2 crankcase side This prevents the tappets from falling into the 1 side when reas sembling crankcase Refer to Figure 11 15 Figure 11 15 Holding Tappets 2 Side Using Governor Spring 3 Place the camshaft into the 1 side of crankcase Make sure the timing mark on crankshaft aligns with the timing mark on cam gear Refer to Figure 11 16 SECTION 11 REASSEMBLY Camgear Timing Mark P Crankshatt Timing Mark Figure 11 16 Alignin
146. s are OFF If ON a spark will occur at the ground cable terminal which could cause an explosion if hydrogen gas or gasoline pors are present va Keep batteries and acid out of the reach of children Battery Maintenance Regular maintenance will ensure the battery will a cept and hold a charge 1 Regularly check the level of electrolyte Add tilled water as necessary to maintain the reco mended level NOTE Do not overfill the battery Poor perfo ance or early failure due to loss of electro lyte will result 2 Keep the cables terminals and external surfa of battery clean A build up of corrosive acid C dis m rm ces or grime on the external surfaces can self discharge the battery Self discharging happens rapidly when moisture is present Wash the cables terminals and extemal surfaces with a baking soda and water solution Rinse thoroughly with clear water SECTION 8 ELECTRICAL SYSTEM AND COMPONENTS NOTE Do not allow the baking soda solution to enter the cells as this will destroy the electrolyte KEY SWITCH The key switch used on Magnum engines equipped with instrument panels is shown in Figure 8 15 Itis three position OFF RUN START break before make type switch Position 1 OFF osition 2 RUN Position 3 START 5 Position Connector Body S Starter B Battery zi KS A Accessory M Module Rear Of Switch Figure 8 15 Key
147. s or bearing surfaces the bearings can be reused Check crankshaft keyways If worn or chipped re placement of the crankshaft will be necessary Also inspect the crankpin for score marks or metallic pick up Slight score marks can be cleaned with crocus cloth soaked in oil If wear limits as stated in Specifications and Tolerances are exceeded it will be necessary to either replace the crankshaft or re grind the crankpin to 010 undersize If reground a 010 undersize connecting rod big end must then be used to achieve proper running clearance Measure the crankpin for size taper and out of round NOTE If the crankpin is reground visually check to insure that the fillet blends smoothly with the crankpin surface Refer to Figure 10 18 10 13 SECTION 10 INSPECTION AND RECONDITIONING High Point From CAMSHAFT VALVE TO Fillet Intersections TAPPET CLEARANCE CHANGE SINE Nee All M18 and M20 engines and short blocks Serial No 1816500656 and later are being built with a new cam shaft and tappets In addition to the new parts new valve to tappet cold clearances apply To service the camshaft and tappets in engines with Serial No 1816500646 and earlier camshaft kit 82 755 09 is available The Fillet Must Blend Smoothly With The Bearing Journal Surtace 45 Minimum This Fillet Area Must Be Completely Smooth Figure 10 18 Crankpin Fillets Serial No New Parts R
148. ses of overheating CJ Check for obvious fuel and oil leaks and dam aged components Excessive oil leakage can in dicate a clogged or improperly assembled breather worn or damaged seals and gaskets or loose or improperly torqued fasteners O Check the air cleaner cover element cover and air cleaner base for damage or indications of im proper fit and seal Also check the seals on the air cleaner cover wing nuts Missing or damaged seals could allow dirt to enter the engine Check the air cleaner element Look for holes tears cracked or damaged sealing surfaces or other damage that could ailow dirt to enter the engine Also note if the element is clogged or re Stricted These could indicate that the air cleaner has been under serviced Check the carburetor throat for dirt Dirt in the throat is further indication that the air cleaner is not functioning properly O Check the oil level Note if the oil level is within the operating range on the dipstick or if it s low or overfilled Check the condition of the oil Drain the oil Into a container it should flow freely Check for metal chips and other foreign particles NOTE It is good practice to drain oil at a loca tion away from the workbench Be sure to allow ample time for complete drainage Sludge is a natural by product of combustion a small accumulation is normal Excessive sludge formation could indicate that the oil has not been changed as recomme
149. shaft lever assembly is non serviceable If the shaft or bore become wom or dam aged the carburetor will have to be replaced If starting or performance problems occur check the air cleaner first and service LPG system components following instructions provided by the equipment man ufacturer If carburetor readjustment is indicated stop the engine and reset the needle adjusting screws to the initia settings shown in Figure 6A 25 then restart the engine allow it to warm up and make final adjust ments on regulators and or carburetor to achieve best perfomance Idle Speed Throttle Shaft Assembly Load Screw 210 2 3 4 Turns Open Idle Fuet Adj Screw 1 3 4 to 2 Fitting Fuel Inlet Turns Open Figure 6A 25 Kohler LPG Carburetor 6A 19 M18 amp M20 SECTION 6B FUEL SYSTEMS CARBURETOR SERVICE WALBRO BUILT Two types of Walbro carburetors are used on the Magnum M18 amp M20 engines One is the fixed main Jet type while the other features an adjustable main or high speed needle These are built to Kohler Co specifications by Walbro Corp This section covers the adjustment disassembly Cleaning inspection repair and reassembly of both types of these Walbro built side draft carburetors with differences called out wherever pertinent Most com ponents are identical Idle Speed Adjusting Screw Figure 6B 1 Walbro Carburetor A WARNING Accidental Starts Before serv
150. sistance is 5 2 6 3 ohms the coil is OK ELECTRIC STARTER If the resistance is low or 0 chms the coil is shorted Replace solenoid if the resistance is infinity ohms the coil is open Replace solenoid Commutator End Cap Brushes And Springs Starter Frame Includes Permanent Magnets Au Thru Bolts Drive End Cap Starter Drive Components oo Starter Assembly Drive Shaft Splines Drive Pinion Dust Cover d Anti drift a Spring E g X Y Stop Gear Spacer 0 Stop Nut Dust Cover Figure 8 17 Bendix Drive Electric Starter BENDIX DRIVE ELECTRIC STARTER The M18 amp M20 engines will use either a Bendix drive starter as shown in Figure 8 17 or a solenoid shift type starter described on pages 8 16 through 8 21 Operation Bendix Drive Type Starter When power is applied to the starter the armature ro tates As the armature rotates the drive pinion moves out on the splined drive shaft into mesh with the fly wheel ring gear When the pinion reaches the end of the drive shatt it rotates the flywheel cranking the engine When the engine starts the flywheel rotates faster than the armature and drive pinion This moves the drive pinion out of mesh with the ring gear and into the retracted position When power is removed from the starter the armature stops rotating and the pinion is held in the retracted position by the anti drift spring
151. stalling Intake Manifold and Carburetor 5 Install the fuel line and hose clamp to fuel pump outlet Refer to Figure 11 48 Speed Control Lever Carburetor Governor Linkage Intake Manifold Figure 11 48 Installing Intake Manifold Carburetor and Governor Arm 6 Install the govemor linkage to governor arm and carburetor throttle lever Install the plain washer and governor arm to cross shaft refer to Figure 11 7 Do not tighten hex nut on governor arm until arm is adjusted Step 7 7 Governor Adjustrnent refer to Figure 11 49 a Grasp the cross shaft with pliers and turn shaft Clockwise as far as it will go b Pull the govemor arm away from carburetor as far as it will go Tighten the hex nut securely Cross Shaft Turn Clockwise Governor Arm Pull Away From Carburetor Figure 11 49 Adjusting Governor Arm Cross Shaft 8 Install governor spring to governor arm and speed control lever Make sure spring is installed in cor rect positions for proper operation SECTION 11 REASSEMBLY INSTALL AIR CLEANER NOTE The Instructions given here are for the basic spec engine with the square style air cleaner If the engine is equipped with an optional style air cleaner refer to the Air Cleaner Sec tion for installation procedures 1 Install the gasket air cleaner base air intake tube breather hose and self tapping screw Re fer to Figure 11 50 NOTE Make sure br
152. start the engine near spilled fuel Never use gasoline as a cleaning agent AWARNING Rotating Parts can cause severe injury Stay away while engine is in operation Rotating Partst Keep hands feet hair and clothing away from all moving parts to prevent injury Never operate the engine with covers shrouds or guards removed A WARNING Hot Parts can cause severe burns Do not touch engine while operating or just after stopping Hot Parts Engine components can get extremely hot from operation To prevent severe burns do not touch these areas while the engine Is running or immediately after it is turned off Never operate the engine with heat shields or guards removed 1 1 SECTION 1 SAFETY AND GENERAL INFORMATION Accidental Starts can cause severe injury or death Disconnect and ground spark plug lead betore servicing Accidental Starts Before servicing the engine or equipment always disconnect the spark plug lead to prevent the engine from starting accidentally Ground the lead to prevent sparks that could cause fires Make sure the equipment is in neutral A CAUTION High Voltagel Never touch electrical wires or components while the engine is running They can be sources of electrical shock WARNING Overspeed Is A Hazardous Do not tamper with the governor setting Overspeed is hazardous and could cause personal injury WARNING Flammable A Solvents Carburetor cleane
153. stener Torque in 7 Closure Plate Oil Gallery Pipe Plug Torque in Ib Cylinder Barrel Nut Torque in 16 7 Crankcase Nut Torque in 5 16 Crankcase Screw Torque in Ib 3 8 Crankcase Screw Torque in Ib Crankshaft Crankshaft End Play Main Bearing Surface Max Wear Limit Sleeve Bearing Max Out of Round Sleeve Bearing Max Taper New Sleeve Bearing Max Sleeve Bearing Running Clearance Max Wear Limi Running Clearance New Sleeve Bearing I D installed Crankpin O D New Crankpin O D Max Wear Limit Crankpin O D Max Out of Round Crankpin O D Max Taper Model M18 140 100 0012 0024 0029 0006 0011 005 016 150 150 65 80 260 0059 1 7439 1 7461 1 3733 1 3738 1 3728 0005 001 Model M20 140 100 0012 0024 0029 0006 0011 005 016 150 150 65 80 260 200 260 002 014 1 7407 0005 1001 0049 0059 1 7439 1 7461 1 4993 1 4998 1 4988 0005 001 17 SECTION 1 SAFETY AND GENERAL INFORMATION Cylinder Bore ID ius eres vu CES ON SNS VSS V D Max Taper Cylinder Head Cap Screw Torque ft Ib 4 Max Out of Flatness
154. ston pin see Figure 10 4 Figure 10 4 Measuring Piston Diameter Style D Piston 2 Use an inside micrometer telescoping gauge or bore gauge and measure the cylinder bore Take the measurement approximately 2 1 2 below the top of the bore and perpendicular to the piston pin 3 Piston to bore clearance is the difference be tween the bore and the piston diameter step 2 minus step 1 VALVES Inspection and Service Carefully inspect valve mechanism parts Inspect valve springs and related hardware for excesslve wear or distortion Valve spring free height should be ap proximately 1 68 1 11 16 Check valves and valve seat area or inserts for evidence of deep pitting cracks or distortion Check clearance of valve stems in guides See Figure 10 5 for valve details and spec ifications for 45 angle or 10 5A for the new 30 ex haust valve See page 10 4 Hard starting or loss of power accompanied by high fuel consumption may be symptoms of faulty valves Although these symptoms could also be attributed to worn rings remove and check valves first After re moval clean valve head face and stem with power wire brush and then carefully inspect for defects such as warped valve head excessive corrosion or wom Stem end Replace valves found to be in bad condi tion A normal valve and valves in bad conditlon are shown in the accompanying illustrations 10 3 SECTION 10 INSPECTION AND RECONDITIONING
155. t if the needles are forced Main Fuel Needle CS Idle Fuel Needle Figure 6A 5 Kohler Built Adjustable Jet Carburetor 2 Preliminary Settings Turn the main fuel and idle fuel adjusting needles out counterclockwise from lightly bottomed as follows 2 1 2 Turns 1 Turn Main Fuel Needle Idle Fuet Needle 3 Start the engine and run at half throttle for 5 10 minutes to warm up Engine must be warm before making final settings Steps 4 6 4 Final Setting Main Fuel Place throttle in wide open position and if possible place engine under load Tum main fuel adjusting needle out coun terclackwise from preliminary setting until the en gine speed decreases rich Note the position of the needle Naw tum the adjusting needie In clockwise Tne engine speed may increase then it will decrease as the needle is tumed in lean Note the posi lion of the needle Set the adjusting need e midway between the rich and lean settings noted Refer to Figure 6A 6 Lean Adjust To 7 Midpoint Figure 6 6 Carburetor Adjustment 5 Final Setting Idle Fuel Place throttle into idle or slow position Set idle fuel adjusting needle using the same procedure as in Step 4 NOTE To ensure best results when setting idle fuel mixture the idle speed must not ex ceed 1500 RPM Typical idle speed is 1200 RPM See Step 6 6 Idle Speed Setting Place throttle into idle or slow positio
156. t insert proceed as follows 1 Make sure valve seat insert bore is clean and free of nicks or burrs 2 Align valve seat insert in counterbore and using valve seat installer and driver Refer to Section 2 Special Tools press seat in until bottomed 3 Use a standard valve seat cutter see Figure 10 10 and cut seat to dimensions shown in Figure 10 5 Valve Seat Cutter Typical Figure 10 10 Standard Valve Seat Cutter Reground or new valves must be lapped in to provide fit Use a hand valve grinder with suction cup for final lapping Lightly coat valve face with fine grade of grinding compound then rotate valve on seat with grinder Continue grinding until smooth surface is ob tained on seat and on valve face Thoroughly clean cylinder barrel in soap and hot water to remove all traces of grinding compound After drying cylinder barrei apply a light coating of SAE 10 oil to prevent rusting Valve Stem Seals These engines use valve stem seals on the intake valves Always use new seals when valves are re moved from cylinder Seals should also be replaced if deteriorated or damaged in any way Never reuse old seals PISTONS AND RINGS Identification Ali Magnum M18 and M20 engines use the new style D pistons and matching piston rings Style D pistons are identified by the installation direction iden tifier Fly which is stamped into the top of the plston and by the rectangular recessed area around t
157. tab and high speed stop bracket from intake elbow SECTION 6A FUEL SYSTEMS AND GOVERNORS Lever Truss Head Spring Washer Nylock Screw TN Locking Tab Throttle Control Friction Washers Throttle Linkage Self Tapping Screw 4 1 Throttle 7 1 Stop Plate Intake Manitold Intake Elbow High Speed Hex Cap Screw Stop Bracket High Speed Stop Tab Speed Control Lever THROTTLE CONTROL ASSEMBLY intake Manifold Knob Carburetor Choke Lever Choke Linkage Hole Hex Head Threads Self Tapping Screw Clamp CHOKE CONTROL ASSEMBLY Figure 6A 21 Engine Mounted Throttle and Choke Controls 5 Remove the self tapping screw and clamp secur ing choke control assembly to intake manifold Disconnect choke linkage from choke lever on carburetor Reassembly 1 Install the high speed stop bracket high speed stop tab speed control lever and hex cap screw to intake elbow Make sure the high speed stop tab does not inter fere with the movement of the speed control lever The high speed stop tab is used as a pivot only Install the throttle stop plate and self tapping screw to intake manifold 3 Connect the throttle linkage to throttle control lever and speed control lever 4 Install the friction washers throttle control lever locking tab spring washer and truss head nylock screw Make sure locking tab is positioned in the hole in throttle stop plate Tighten the nyloc
158. talls at idle speed speed screw then adjust idle fue needle Engine runs rich indicated by black 2a Choke closed during operation Check the choke lever and linl sooty exhaust smoke misfiring loss of age to ensure choke is opening after warm up speed and power governor hunting b Idle and or main fuel mixture improperly adjusted Adjust idle and or main excessive throttle opening fuel needle C Float level set too high With fuel bowl removed and carburetor inverted set exposed surface of float parallel with the bowl gasket surface of carbu retor body d Dirt under fuel inlet needle Remove needle Clean needle and seat and blow with compressed air Bowl vent or air bleeds plugged Remove fuel bowl idle fuel adjusting needle and welch plugs Clean vent ports and air bleeds Blow out all passages with compressed air f Fuel bowl gasket leaks Remove fuel bowl and replace gasket g Leaky cracked or damaged float Submerge float to check for leaks 3 Engine runs lean Indicated by misfir 3a Idie and or main fuel mixture improperly adjusted Adjust idle and or main ing loss of speed and power governor fuel needle hunting or excessive throttle opening Ficat level set too low With fue bowl removed and carburetor inverted set exposed surface of float parallel with the bow gasket surface of carburetor body c idle holes plugged dirt in fuel delivery channels Remove fuel bowl idle fuel
159. that it is slightly loose 2 Rotate the choke unit clockwise on the carburetor viewed from the choke side with a slight pres sure until the choke valve is positioned 4 to 6 de grees towards the closed position 3 While holding the choke unit in the above posi tion tighten the two mounting screws 4 This adjustment must be accomplished at an am bient temperature of 70 75 F Shutdown Control Function The engine shutdown control device is a solenoid and plunger mounted on the carburetor which prevents the engine from running on after the ignition is turned off See Figure 6A 23 When the switch is in the start po sition battery current thru the solenoid holds the plunger and continues to hold it while the engine is running When the switch is moved to the stop posi tion the solenoid de energizes and drops the plunger into a porting in the carburetor to stop all flow of fuel The engine shutdown control has two lead wires on it a ground lead from the top of the shutdown sole noid and a power lead from the bottom of the sole noid The power lead is wired into the 4 side of the rectitier regulator Shutdown Control Inspection 1 Make sure the solenoid has a secure electrical connection and good contact with the retaining bracket ground 2 Check for stuck plunger Replace if damaged 3 Check tor defective solenoid with an ohmmeter or multimeter Solenoid resistance is approximately 20 ohms Shutdown Contr
160. the engine Always observe and use the following precautions and procedures when installing the flywheel NOTE A Before installing the flywheel make sure the crankshaft taper and flywheel hub are clean dry and completely free of lubricants The presence of lubricants can cause the flywheel to be over stressed and damaged when the cap screw is torqued to specification B Make sure the flywheel key is installed only in the flat area of keyway not in the rounded area The flywheel can become cracked or damaged if the key is installed in the rounded area of keyway C Always use a flywheel strap wrench to hold flywheel when tightening the flywheel fastener Do not use any type of bar or wedge between the cooling fins or flywheel ring gear as these parts could become cracked or damaged Install the spacers fan and hex flange screws Refer to Figure 11 36 Flywheel Hex Flange Screws 4 Figure 11 36 installing Fan To Flywheel 2 Place the flywheel on crankshaft and Install plain washer split lock washer and hex cap screw lu bricate threads with oil Refer to Figure 11 37 Figure 11 37 Installing Flywheel Fastener 3 Hold the flywheel with the strap wrench and torque the hex cap screw to 40 ft Ib 4 Install the grass screen to fan 11 13 SECTION 11 REASSEMBLY INSTALL BRACKET AND IGNITION MODULE 1 Install the bracket and hex flange screws to 1 cylinder barrel Ma
161. the groove on the armature shaft NOTE Always use a new retainer Tighten the retainer in the groove to secure 8 20 Figure 8 36 Installing the Stop Collar Fit the front stop collar over the shaft and bring the front and the rear stop collars together over the retainer Using two pairs of pliers apply even force to the two collars until they snap over the retainer and nest into one another SECTION 8 ELECTRICAL SYSTEM AND COMPONENTS 4 Note that the cross section of the brush spring is oval not circular therefore inserting this spring with its longer axis facing upwards makes installa tion easier Brush spring Figure 8 37 installing the Brush Springs 5 Reassemble the remaining components of the starter in reverse order of disassembly 8 21 M18 amp M20 SECTION 9 DISASSEMBLY A WARNING Accidental Starts Before servicing the engine or equipment always remove the spark plug leads to prevent the engine from starting accidentally Ground the leads to pre vent sparks that could cause fires The following sequence is suggested for complete engine disassembly This procedure may have to be varied slightly to accommodate options or special equipment Clean all parts thoroughly as the engine is disassem bled Only clean parts can be accurately inspected and gauged for wear or damage There are many commercially available cleaners that quickly remove grease oil and grime fro
162. tric starter current amp draw The Engine Analysis Kit can be ordered complete as shown or the instruments can be ordered individually Contact your Kohler Distributor for price and availability 25 SECTION 2 SPECIAL TOOLS IGNITION SYSTEM TESTER Magnum engines use a state of the art electronic ignition module A simple tester can be used to determine if the ignition module is functioning properly Spring Clip P ENS Additional Components For Y Twin Cylinder Engines Spark Plug 1 2 1 0 Fuel Line Y 1 1 4 Long 4 F 18 GA Wire Remove Ground Electrode Spark Plug 0 025 Gap Spring Clip Alligator Clip 1 2 1 0 Fuel Line 1 1 4 Long Figure 2 3 Electronic Ignition System Tester For Twin Cylinder Engines 5 Obtain another new RJ 8 or RCJ 8 spark piug Models M18 and M20 Set the gap to 0 035 1 Obtain a new RJ 8 or RCJ 8 spark plug 6 Obtain another large spring clip Attach the spring clip to the new spark plug Connect the alligator clip from the single cylinder tester to the screw terminal end of the spring clip 2 Remove the ground electrode from the spark plug This gives a spark gap of 0 13 This large gap simulates the spark required under actual engine conditions 7 Install a 1 1 4 length of 1 2 1 D fuel line onto the 3 Make a lead assembly using a large spring clip threads of the ne
163. tructed of a nylon material The nylon body insulates the fuel from the hot engine crankcase and prevents fuel from vaporizing inside the pump Operation The mechanical fuel pump is operated by a lever which rides on the engine camshaft The lever trans mits a pumping action to the diaphragm inside the pump body Tnis pumping action draws fuel in through the inlet check valve on the downward stroke of diaphragm On the upward stroke of the dia phragm the fuel is forced out through the outlet check valve Refer to Figure 6A 3 6A 2 SECTION 6A FUEL SYSTEMS AND GOVERNORS Outlet Camshaft Check Valve Fuel Pump Lever Inlet Diaphragm Check Valve Figure 6A 3 Mechanical Fuel Pump Removal 1 Disconnect the fuel lines from the inlet and outlet fittings of pump 2 Remove the truss head nylock screws fuel pump and gasket 3 If necessary remove the fittings from pump body Repair Nylon bodied fuel pumps are not serviceable and must be replaced when faulty Replacement pumps are available in kits which include the pump and mounting gasket Installation Refer to Figure 6A 4 Fittings 25 yw Truss Head Nylock Screws Figure 6A 4 Installing Fuel Pump 1 Fittings Apply a small amount of Permatex Avi ation Perm A Gasket or equivalent gasoline re sistant thread sealant to fittings Tum fittings into pump 6 full turns continue tuming fittings in same direct
164. ts Remove Throttle Plate and Throttle Shaft Transfer Throttle Lever 1 To ensure correct reassembly mark throttle plate and carburetor body with a marking pen Also take note of throttle plate position in bore and throttle lever position Carefully and slowly remove the screws securing the throttle plate to throttle shaft Remove and save the throttle plate as it will be reused File off any burrs which may have been left on throttle shaft when screws were removed Remove the throttle shaft from carburetor body Remove and discard the foam rubber dust seal from throttle shaft 5 Remove transfer throttle lever as follows Note the position of the throttle lever with re spect to the cutout portion of throttle shaft Carefully grind or file away the riveted portion of shaft remove throttle lever Carefully compare the old shaft to the new shafts from kit Select the appropriate new shaft and discard the old shaft install throttle lever to throttle shaft Make sure lever is installed correctly as noted in Step a Apply Loctite to threads of 1 42 56 x 7 32 brass screw use 43 48 x 7 32 screw with 2 49 64 shaft secure lever to shaft b 6A 8 SECTION 6A FUEL SYSTEMS AND GOVERNORS Drill Choke Shaft Bores Using a Drill Press 1 Mount the carburetor body in a drill press vise Keep vise slightly loose 2 Install a 1 4 dia drill in drill press chuck Lower drill not rotating through both
165. twin cylinder engine _ SERVICE MANUAL VASGNUM MODELS M18 amp M20 KOHLER engines TP 2204 8 CONTENTS SECTION 1 Safety and General Information SECTION 2 Special Tools SECTION 3 Periodic Maintenance SECTION 4 Troubleshooting SECTION 5 Air SECTION 6A Fuel Systems and Governors Kohler Carburetors 6B Fuel Systems Walbro Carburetors SECTION 7 Lubrication System SECTION 8 Electrical System and Components SECTION 9 Disassembly SECTION 10 Inspection and Reconditioning SECTION 11 E E3 of of IPSE IER EL IER IPC SECTION 1 M18 amp M20 SAFETY AND GENERAL INFORMATION SAFETY INFORMATION For Your Safety These precautions should be followed at all times Failure to follow these precautions could result in injury to yourself and others A WARNING Explosive Fuel can cause fires and severe burns Stop engine before filing fuel tank Explosive Fuel Gasoline is extremely flammable and its vapors can explode if ignited Store gasoline only in approved containers in well ventilated unoccupied buildings away from sparks or flames Do not fill the fuel tank while the engine is hot or running since spilled fuel could ignite if it comes in contact with hot parts or sparks from Ignition Do not
166. ump Fuel then enters the carburetor float bow and is moved into the carbu retor body where it is mixed with air This fuel air mix ture is then burned in the engine combustion chambers Fuel Tank Equipment or Remote Mounted Fuel Line Vented Fuel Tank Cap S Fuel Pickup Tube With Screen In line Fuel Filter Troubleshooting Use the following procedure to check if fuel is reach ing the combustion chamber A WARNING Explosive Fuel Gasoline is extremely flammable and its vapors can explode if ignited Before troubleshooting the fuel system make sure there are no sources of heat flames or sparks nearby as these can ignite gaso line vapors Disconnect and ground the spark plug leads to eliminate the possibility of sparks from the ignition system Intake Manifold To Combustion Chambers Carburetor Fuel Line Fuel Line Camshaft Figure 6A 1 Typical Fuel System A 1 SECTION 6A FUEL SYSTEMS AND GOVERNORS Test Conclusion 1 Check for the following A Make sure the fuel tank contains fuel B Make sure the vent in fuel tank cap is open C Make sure the fuel shut off valve is open 2 Check for fuel in the combustion chamber A Disconnect the spark plug leads B Close the choke on carburetor Crank the engine several times D Remove the spark plugs and check for fuel at tips 2 If there Is fuel at tips of spark plugs
167. ure the valve to tappet clearance for the remaining cylinder 3 If clearance is too small remove the valves and grind the valve stems until the correct clearance Is Obtained Make sure valve stems are ground per fectly flat and smooth If clearance is too large replace the valves and recheck clearance NOTE Large clearance can also be reduced by grinding the valves and or valve seats Refer to the Inspection And Repair Reconditioning Section for valve specifications Reinstall Spark Plugs Breather Valve Covers and Air Cleaner 1 Reinstall spark plugs and torque to 10 15 ft Ib 2 Reinstall valve cover to 22 cylinder barrel Reinstall breather assembly and valve cover to 1 cylinder barrel Make sure breather is as sembled correctly using new gaskets 3 Reinstall air cleaner base to intake manifold and air intake elbow using new gasket 4 Insert end of breather tube through hole in air cleaner base NOTE Make sure breather tube seals tightly in breather cover and in air cleaner base to prevent unfiltered air from entering engine 5 Reassemble remaining air cleaner components and tighten wing nut s 1 2 to 1 full turn after nut contacts cover Do not overtighten 6 Reconnect spark plug leads 3 7 SECTION 3 PERIODIC MAINTENANCE STORAGE If the engine will be out of service for approximately two months or more use the following storage procedure 1 Clean the exterior surfaces of the engine
168. utator End Cap Drive End Cap Figure 8 20 Starter Assembly Match Marks 3 Install the brush holder tool to keep the brushes in the pockets of commutator end cap Refer to Figure 8 19 4 Install the commutator end cap to armature and starter frame Firmly hold the drive end cap and commutator end cap to the starter frame Remove the brush hotder tool 5 Make sure the match marks on end cap and frame are aligned Refer to Figure 8 20 Install the thru bolts and tighten securely 8 15 SECTION 8 ELECTRICAL SYSTEM AND COMPONENTS 6 Install the drive pinion dust cover spacer anti drift spring stop gear spacer stop nut and dust cover Refer to Starter Drive Service SOLENOID SHIFT ELECTRIC STARTER This subsection covers the Nippendenso solenoid shift electric starter Much of the information in the preceding subsection relates to this starter therefore it is not repeated here Please use the exploded view Figure 8 21 for reference during the disassembly and assembly procedure Operation When power is applied to the starter tne electric sole noid moves the drive pinion out onto the drive shaft and into mesh with the flywheel ring gear When the Pinion reaches the end of the drive shaft it rotates the flywheel and cranks the engine When the engine starts and the start switch is released the starter solenoid is deactivated the drive lever moves back and the drive pinion moves out of mesh with t
169. ve the level in the open side If there is no vacuum level in engine side is the same as Crankcase vacuum is best measured with a water open side or a positive pressure level in open Kohler pat hn 25 80050 Is recom side is higher than engine side check for the con mended Complete instructions are provided in kit ini ditions below Test the crankcase vacuum with the manometer as 4 Close the shut off clamp before stopping the follows engine NO CRANKCASE VACUUM PRESSURE IN CRANKCASE Possible Cause Solution Disassemble breather clean parts thoroughly reassemble and recheck pressure 2 Seals and or gaskets leaking Loose or improperly 2 Replace all worn or damaged seals and gaskets 1 Crankcase breather clogged or inoperative torqued fasteners Make sure fasteners are tightened securely Use appropriate torque valves and sequences when necessary 3 Piston blowby or leaky valves Confirm with com 3 Recondition piston rings cylinder bores valves pression or cylinder leakdown test and valve guides 4 Restricted exhaust 4 Replace restricted muffler exhaust system 4 3 SECTION 4 TROUBLESHOOTING Compression Test 3 Crank the engine using the starter motor Take To test compression several readings for both cylinders 1 Remove the spark plugs Install compression tes If the difference in pressure between cylinders is ter in each spark plug hole 15 or greater or pressure is l
170. w spark plug an alligator clip and 18 gauge wire as shown 4 Cut a 1 1 4 length of 1 2 1 0 fuel line and slide Using The Tester it onto the threads of the test plug The fuel line will shade the firing tip to make the spark more Follow the instructions given in the Electrical System visible and Components Section 2 6 SECTION 2 SPECIAL TOOLS RTV SILICONE SEALANT RTV silicone sealant is used as a gasket between the crankcase closure plate and cylinder barrels An easy to use silicone sealant dispenser tube Part No 52 597 02 is available This dispenser tube contains 2 8 fl oz of RTV 108 To order contact your source of supply WATER MANOMETER The Kohler Part No 25 800 50 U Tube water manome ter is a useful tool to check crankcase vacuum or pressure and to check for exhaust back pressure can also be used to adjust primary regulators used with gaseous fuel systems Complete instructions are provided in the kit CYLINDER LEAKDOWN TESTER The Kohler Part No 47 800 02 Cylinder Leakdown Tes ter is a valuable alternate to a compression test By pressurizing the combustion chamber from an extemal air source this tool can determine if valves or rings are leaking Instruction for using this tester are found on page 4 4 of this manual 27 M18 amp M20 SECTION 3 PERIODIC MAINTENANCE REQUIRED MAINTENANCE These required maintenance procedures should be performed at the
171. wing components refer to Figure 8 1 A magnet assembly which is PERMANENTLY af fixed to the flywheel An electronic magneto ignition module which is mounted to the 1 side cylinder barrel Akill switch or key switch which stops the en gine by grounding the ignition module Operation As the flywheel rotates and the magnet assembly moves past the ignition module a low voltage is in duced in the primary windings of the module When the primary voltage is precisely at its peak the mod This high voltage creates a spark at the tip of the spark plugs igniting the fuel air mixture in the cam bustion chambers The timing of the spark Is automat ically controlled by the module Therefore no ignition timing adjustments are necessary or possible with this System NOTE Do not connect 12 volts to the ignition system or to any wire connected to the ignition module The ignition system operates independently of the battery starting charging and other auxil iary electrical systems Connecting 12 volts to the ignition module can cause the module to bum out This type of damage is not cov ered by the engine warranty A break before make type key switch is re quired to prevent damage to the ignition ule induces a high voltage in its secondary windings module Optional Diode Ignition Module 008 012 IL Spark i i Air Gap Plugs Fe 7 High Tension High Tension Lead

Kohler M20 User's Manual

Contents

Download Pdf Manuals

Related Search

Related Contents