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Elite Series E125H, E140H

1. 067 Seat Angle 45 2 3 All dimensional tolerances and clear FACTORY SPECIFICATION ALLOWABLE M teres desea O mmm mac MT EXHAUST VALVE Valve Stem O D 7 940 7 960 0 3126 0 3134 Valve Guide I D 8 000 8 015 0 3150 0 3156 Valve Stem to Valve Guide Clearance 0 04 0 08 0 10 002 003 004 Valve Lash 0 15 0 25 006 0 010 Face Angle 45 EXHAUST VALVE SEAT Seat Width 1 1 1 7 0 043 0 067 Seat Angle 45 VALVE SPRINGS INTAKE AND EXHAUST Valve Spring Free Length Approx 43 5 1 713 Valve Spring Length Valve Closed 32 6 1 28 Valve Open 23 2 0 91 Spring Load Valve Closed Length 12 6 kg 14 6 kg 27 7 b 32 1 Ib Spring Load Valve Open Length 26 4 kg 28 4 kg 24 9 kg 58 2 Ib 62 7 Ib 55 Ib VALVE ROCKER ARM Rocker Arm Bore 1 D 12 000 12 018 0 4724 0 4718 Rocker Arm Shaft O D 11 973 11 984 0 4714 0 4718 Rocker Arm to Rocker Shaft Clearance 0 016 0 045 0 15 0 0006 0 0018 0 0059 2 4 All dimensional tolerances and clear FACTORY SPECIFICATION ALLOWABLE in milli E LIMIT ee O MINIMUM MAXIMUM LUBRICATING SYSTEM Rotor Lobe Clearance 0 15 or less 0 20 0 006 or less 0 008 Outer Rotor to Pump Body Clearance 0 12 0 19 0 25 0 005 0 007 0 010
2. 0 004 0 008 0 010 Journal Bearing O D 17 975 17 990 17 93 7077 7083 7059 Journal Bearing Clearance in gearcase 0 01 0 05 0 08 0004 0020 0031 BALANCER SHAFTS End Clearance Both Shafts 0 10 0 20 0 25 0 004 0 008 0 010 Journal Bearing O D 21 875 21 890 21 83 0 8612 0 8618 0 8594 Journal Bearing Clearance in gearcase 0 02 0 056 0 08 0 0008 0 0022 0 0031 2 1 All dimensional tolerances and clear FACTORY SPECIFICATION ALLOWABLE ances are in millimetres inches at 21 C LIMIT 70 F unless otherwise indicated CRANKSHAFT Stroke 70 70 2 76 2 76 Connecting Rod Journal O D Standard 33 475 33 485 1 3179 1 3183 25 Undersize 39 225 39 235 1 3081 1 3085 50 Undersize 32 975 32 985 1 2982 1 2986 End Clearance 0 10 0 20 0 25 004 008 0 010 CONNECTING ROD Pin Bore I D 20 015 20 025 20 071 0 7880 0 7884 0 7902 Large Bore I D Standard 33 500 33 525 1 3189 1 3199 25 Undersize 33 250 33 275 1 3091 1 3100 50 Undersize 33 000 33 025 1 2992 1 3002 Large Bore Clearance 0 015 0 050 0 100 0 0006 0 0020 0 0040 Side Clearance on Crankshaft 0 40 1 10 1 50 0 016 0 043 0 059 PISTON Piston Skirt O D 90 Degrees to Pin and 26 5 mm 1 043 inch from Top of Piston Standard 84 09 84 12 3 311 3 31
3. engine running If stator output is less than specified go to Step 4 If stator output is as 4 Check to see that the connections at the termi e peo did nals of the voltage regulator three are clean and tight Shut down the engine and check for electrical resistance between either alternator stator lead 5 Check to see that the wiring connected to the and ground bare engine metal using an ohm B terminal middle of the voltage regulator is meter The meter should indicate infinite resis not damaged shorted or grounded tance on its highest scale If resistance is high go to Step 5 If not replace the stator 6 To ensure a good ground path to battery nega tive check to see that the voltage regulator Check alternator stator resistance by connect mounting surface is clean and that the screws ing an ohmmeter across the stator leads Re are tight place the alternator stator assembly if stator re sistance on the lowest scale of the meter is ei i ther higher or lower than specified Replace the 7 Check to see that the positive and negative bat flywheel assembly if alternator stator resis tery cables have good connections at the bat tery and engine and that they are not damaged After checking all of the above perform the following tests if there still is no alternator output when the en gine is running between 1800 and 3600 RPM Refer tance is as specified but alternator stator output is less than specified The pr
4. servicing the 12 VDC output system Approx 29 VAC Q 5 amp system A CAUTION Operation with reversed positive Ode and negative battery connections or without connection to a battery will damage the voltage regulator and or the alternator stator k Never reverse the battery leads 1800 RPM Ohms 20 amp system 0 27 to 0 33 Ohms Any Speed Within Operat amp 57 VAC 3600 RPM ing Range Check battery voltage when the engine is not running If not within specifications Table 6 1 2 Charging system tests require a fully charged charge the battery before going to Step 2 battery in good condition Make sure the engine is being run long enough and fast enough in With the engine running check voltage regula service to recharge the battery after each start tor output DC voltage at the battery terminals Alternator output is proportional to engine Replace the voltage regulator if output is speed and accessories consume power other greater than specified If voltage regulator out wise available for battery recharging put is less than specified go to Step 3 3 The voltage regulator has built in protection Disconnect the alternator stator leads from the against open circuit and short circuit faults B voltage regulator see Figure 6 4 and test for terminal It will not turn on under either condi alternator stator output AC voltage with the tion or when battery discharge is extreme
5. 14 0 bhp brake horse power and 125 12 5 bhp 3 Shaft Orientation V designates vertical shaft and H horizontal shaft 4 Engine Fuel N designates gasoline D LPG and D dual fuel 5 Optional Equipment Code designates muf fler fuel tank electric starter etc or combina tions thereof 6 Spec Letter designates production modifica tions AWARNING IMPROPER SERVICE OR REPLACEMENT OF PARTS CAN RESULT IN SEVERE PERSONAL IN JURY AND EQUIPMENT DAMAGE SERVICE PERSONNEL MUST BE QUALIFIED TO PERFORM ELECTRICAL AND MECHANICAL SERVICE 1 1 1 2 Section 2 Tolerances and Clearances All dimensional tolerances and clear FACTORY SPECIFICATION ALLOWABLE in milli LIMIT ep i e camisa medi MINIMUM MAXIMUM CYLINDER BLOCK Cylinder Bore I D Standard 84 200 84 225 84 325 3 3150 3 3160 3 3199 25 Oversize 84 450 84 475 84 575 3 3248 3 3258 3 3297 50 Oversize 84 700 84 725 84 825 3 3347 3 3356 3 3396 Cylinder Bore Taper 0 10 0 004 Cylinder Bore Out of Round 0 05 0 002 CAMSHAFT Lobe Height Diameter Over Nose E125 Intake 34 23 34 55 33 13 1 348 1 360 1 328 E125 Exhaust 34 53 34 85 34 03 1 359 1 372 1 340 E140 Intake 35 09 35 41 34 59 1 381 1 394 1 362 E140 Exhaust 35 09 35 41 34 59 1 381 1 394 1 362 End Clearance 0 10 0 20 0 25
6. Assembly Accidental starting of the engine can result in severe personal injury or death Disconnect the negative battery cable and spark plug wire before servicing the engine controls or associated equipment CYLINDER COMPRESSION TEST It is recommended that a cylinder compression test be performed to determine the condition of valves piston piston rings and cylinder To check cylinder compression pressure 1 Run the engine until it is thoroughly warm stop it and remove the spark plug 2 Remove the air cleaner and place the throttle and the choke in their wide open positions 3 Insert the compression gauge in the spark plug hole crank the engine and read the pressure The compression gauge should indicate at least 483 kPa 70 psi There may be variations due to equipment temperature atmospheric conditions and altitude This value is for a warm engine at cranking speed about 300 rpm FLYWHEEL REMOVAL Improper flywheel removal can result in severe personal injury Loosen the flywheel nut only a couple of turns before using a flywheel puller so that the nut will restrain the flywheel when it breaks loose from the shaft ta per It is necessary to remove the flywheel when rebuild ing the engine block assembly or gaining access to the battery charging alternator stator see Section 6 Electrical System To remove the flywheel remove the recoil starter assembly if so equipped including the cup on the fly
7. Clearances rebore the cylin der to the next oversize 6 The differences between A and C and be tween B and D indicate cylinder out of roundness If cylinder out of roundness ex ceeds that specified in Section 2 Tolerances and Clearances rebore the cylinder to the next oversize 7 If cylinder taper and out of roundness are with in specifications it will only be necessary to de glaze the bore The old piston can be reused if it is not worn or damaged New piston rings should always be used TOP OF CYLINDER Precision Honing Refer to the hone manufactur BOTTOM OF RING TRAVEL FIGURE 9 31 LOCATIONS FOR MEASURING CYL INDER BORE DIAMETER Reboring and or Honing the Cylinder Rebore and or hone a scuffed out of round ta pered or otherwise worn cylinder to the next over 4 size bore Section 2 Tolerances and Clearances Honing should produce a 20 to 40 RMS surface fin ish with a 23 degree crosshatch pattern Figure 9 32 for rapid piston ring break in FIGURE 9 32 PROPER HONE CROSSHATCH IN BORE Improper boring honing can dam age the engine block beyond repair It should be done by a qualified engine shop with proper 7 equipment Boring When reboring the cylinder make sure that the top of the engine block is smooth and deposit free and that the base of the boring bar is clean De posits between the boring bar and block will cause it to tilt and bore at
8. Rotor to Cover Clearance 0 02 0 09 0 25 0 001 0 004 0 010 IGNITION SYSTEM Spark Plug Gap 0 89 1 02 0 035 0 040 Magneto Coil to Rotor Magnet Clearance 0 25 0 40 0 010 0 016 STARTER MOTOR Commutator O D 28 0 27 00 1 102 1 063 Difference of Commutator O D s 0 05 0 016 0 002 0 41 Armature Shaft to Bushing Clearance 0 02 0 07 0 20 0 001 0 003 008 Mica Undercut 0 45 0 75 0 20 0 018 0 030 0 008 2 5 2 6 Section 3 Assembly Torques DESCRIPTION BOLT METRIC ENGLISH INSTRUCTIONS SIZE N m LB FT Connecting Rod Bolts M8 x 44 24 27 18 20 th r Its in a clockwi irection startin Gearcase Bot Te we ee NUMINE LAM d dhasie th Oil Pump Cover Screws M6 x 14 7 11 5 8 BOLTA amp Oil Pickup Tube M6 x 14 7 11 5 8 JO cr Oil Drain Plugs 1 4 NPT 7 11 5 8 BENEGAS Bl ARE 1 8 NPT 7 9 5 5 7 BOLTS LOPCO or Pipe Plug 1 8 NPT 7 9 5 5 7 Adapter Filter Head 3 4 16 47 54 35 40 Oil Filter Turn the oil filter 3 4 1 turn after gasket contacts base Cylinder Head Bolts e M10 x 66 Torque the cylinder head bolts in sequence shown Two i No 1 5 Bolts 86 125 42 50 31 37 bolts outside valve cover 2 amp 4 to be retorqued after I j others are torqued Hu No 6 Flange Bolt M8 x 50 16 22 12 16 o Lash Adjusting M7 7 41 5 8 S Nut Valve Rocker M6 x 25 7 41 5 8 Tighten every other valve rocker cover bo
9. a EE 9 3 cuuccp P rUTT 9 4 Engine Disassembly Assembly uu erai i atii i non t eus dise dene a ea 9 7 t cprLOM 9 8 tor 9 9 Balaucer nallo eavceaseegene contes es ee aes ceda des PI MUNI Ed bala p dor d caus 9 9 Crankshaft and Camshaft 0 0 00 ee een een eee ee nee ene nennen nenn 9 10 Compression Release System 0 ccc ee ene nent e ene e hne 9 11 Piston Connecting Rod esmas radica dba dee trend rabassa canes 9 12 PNOING E 9 16 A A A 9 18 Crankshaft Oil Seals omcscsorsesesprds iris ras AG 9 18 Section 1 Introduction This is the service manual for the Model E125H and E140H engines These are 1 cylinder 4 stroke cycle spark ignited overhead valve OHV air cooled engines Table 1 1 summarizes other in formation about these engines TABLE 1 1 USEFUL ENGINE INFORMATION MODEL MODEL FEATURE E125H E140H Rated Power 389 cm 23 7 inch 84 2 mm 3 31 inch 70 mm 2 76 inch 8 5 1 Displacement Bore Stroke Compression Ratio Minimum Cylinder Compression Test 483 kPa 70 psi Pressure Lubricating Cil 0 95 litre Capacity with filter 1 quart Minimum Lubricating Cil Pressures at 1500 3300 rpm Beginning Spec D New 80 138 kPa 13 20 psi Worn 62 103 kPa 9 15 psi Minimum Lubricating Oil Pressures at 1500 3300 rom Prior to Spec D N
10. an angle to the true cylinder axis 8 9 17 il er s recommended grit size to produce the specified surface finish of 20 to 40 RMS Position the engine block solidly for either verti cal or horizontal honing Use either a drill press or heavy duty drill which operates at approxi mately 250 to 450 rpm Follow the hone manufacturer s instructions for the use of oil or lubricant on stones Do not use lubricants with a dry hone Insert the hone in the cylinder and adjust the stones to fit snugly to the narrowest section When adjusted correctly the hone should not shake or chatter in the cylinder bore but will drag freely up and down when the hone is not running Connect the drill to the hone and start it Feel out the bore for high spots which cause an in creased drag on the stones Move the hone up and down in the bore with short overlapping strokes about 40 times per minute Usually the bottom of the cylinder must be worked out first because it is smaller As the cylinder takes a uniform diameter move the hone up and down all the way through cylinder bore Check the diameter of the cylinder regularly during honing A dial bore gauge is the easiest way but a telescoping gauge can also be used Measure bore size at six places in the cylinder measure twice at top middle and bottom at 90 degree angles The crosshatch formed by the stones should form an included angle of 23 degrees This can be achieved by moving the
11. check that the right piston size has been obtained measure the diameter as indicated in Section 2 Tolerances and Clearances To double check that the right piston ring size has been ob tained insert one of the rings in the package into the cylinder and square it up with the piston Then mea sure the ring gap with a feeler gauge The gap must be as specified BALL BEARINGS The gearcase carries one crankshaft ball bearing assembly and the engine block the other The en gine block also carries ball bearing assemblies for the camshaft and the two balancer shafts Use a bearing puller to remove these bearings from the gearcase and block Clean the bearing mounting surfaces before pressing in new bearing assem blies CRANKSHAFT OIL SEALS Use an oil seal remover to pry the crankshaft oil seals out of the engine block and gearcase Clean the oil seal seating surfaces and lubricate the sur faces before installing new oil seals Press the new oil seals into the engine block and gearcase until they are flush in their bores Apply a light coating of grease to the lips of the oil seals to provide lubrica tion until engine oil reaches them 9 18 Onon Cummins Power Generation 1400 73rd Avenue N E Minneapolis MN 55432 763 574 5000 Fax 763 528 7229 Cummins and Onan are registered trademarks of Cummins Inc
12. control cables and idle speeds be adjusted properly The governor arm Figure 5 5 must be re positioned on its shaft whenever the intake manifold or carburetor is replaced or reinstalled This must be done BEFORE making speed adjustments so as to compensate for the slightly different alignment of parts after reassembling the carburetor or intake manifold to the engine See Section 9 Engine Block Assembly regarding the internal governor parts The governor arm and shaft have been designed so that a standard battery cable clamp lifter available at any automotive parts store can be used to pull the arm from the shaft taper Accidental starting of the engine can result in severe personal injury or death Al ways disconnect the spark plug and battery negative cable before adjusting the gover nor Governor Arm Removal 1 Remove throttle link 4 from governor arm 6 to prevent damage to the link and carburetor GOVERNOR SPRING 1 THROTTLE LINK 4 GOVERNOR ARM 6 2 Loosen lock nut 3 until it extends slightly be yond the end of the shaft 3 Place the puller arms around the hub of the governor arm center the puller screw so that it bears on the lock nut and then turn the screw until the governor arm breaks loose Governor Arm Adjustment 1 Loosely assemble the governor arm to the gov ernor shaft and start the lock nut 2 Re attach link 4 to the governor arm and carbu retor Replace clips
13. holes in each control arm Make sure the wires are hooked appropriately as shown for the cable clamp location being used Other wise the cable will bind preventing full move ment Rotate the choke and throttle control arms clockwise and while holding them against their stops pull the slack out of the cables and tight en the cable clamp Check for smooth movement and full travel of the equipment choke knob and throttle lever Remove the air cleaner element as instructed in this section to see that the choke plate opens and closes fully Move the equipment throttle le ver to see that the throttle control arm touches the stop plate and that the throttle shaft arm touches the stop screw Reassemble the air cleaner and reconnect the spark plug and battery CHOKE CABLE 44 SLACK OUT THIS WAY CHOKE CABLE above throttle cable ALTERNATE CABLE CLAMP LOCATIONS FULL OPEN CHOKE POSITION CONTROL ARM NUM above throttle 777 ota control arm THROTTLE CABLE SLACK OUT THIS WAY STOP PLATE HIGH IDLE ALTERNATE CABLE CLAMP LOCATIONS VEEAMEEEEEREHIEFHIEFEEEFFA B AF THROTTLE 2 CABLE below choke cable 4 gt e AM TTS THROTTLE SHAFT ARM AND STOP SCREW LOW IDLE THROTTLE CONTROL ARM below choke control arm FIGURE 5 6 CHOKE AND THROTTLE CABLES ENGINE SPEED ADJUSTMENTS Engine speed adjustment must be attempted only by a qualified mechanic and the adj
14. the corresponding shaft diameters Re place the bushings if the clearances are greater than specified Section 2 Tolerances and Clear ances BUSHING FIGURE 7 11 MEASURING BUSHING I D AND AR MATURE SHAFT O D 7 6 Section 8 Lubrication System Improper service or replacement of parts can result in severe personal injury and or equipment damage Service personnel must be qualified to perform electrical and mechanical service An oil pump is used to provide pressure lubrication via the oil filter to the journal bearings in the gear case and to the crankshaft connecting rod journal Figure 8 1 The oil pump is located in the gearcase and is driven by a balancer shaft It is accessible by removing the oil pump cover on the gearcase Fig ure 8 3 Oil pressure is controlled by an oil relief valve Figure 8 7 Refer to the Operator s Manual for lubricating oil specifications and instructions on how to check the oil level and change the oil and oil filter The crank case and oil filter hold 0 95 litre 1 quart of oil CRANKSHAFT CONNECTING ROD JOURNAL FIGURE 8 1 OIL HOLE IN THE CRANKSHAFT CON NECTING ROD JOURNAL CHECKING OIL PRESSURE Refer to Figure 8 2 Install an engine oil pressure gauge in the gearcase as shown The engine will have an oil pressure switch or a 1 8 inch pipe plug in the tapped hole Start the engine and observe the oil pressure as the engine warms up The oil pressure should not be
15. 2 25 Oversize 84 34 84 37 3 320 3 322 50 Oversize 84 59 84 62 3 330 3 331 Pin Bore I D 20 004 20 012 20 022 0 7876 0 7879 0 7883 2 2 All dimensional tolerances and clear FACTORY SPECIFICATION ALLOWABLE in milli LIMIT Uu i erecta desea MINIMUM MAXIMUM PISTON PIN Piston Pin O D 20 000 20 005 19 990 0 7874 0 7876 0 7870 Clearance in Piston Pin Bore 001 012 0 03 0000 0 0005 0 0012 Clearance in Connecting Rod Pin Bore 010 025 035 0 0004 0 0010 0 0014 PISTON RINGS Top Compression Ring Thickness 1 47 1 49 1 42 058 059 056 Second Compression Ring Thickness 1 47 1 49 1 42 058 059 056 Top Compression Ring to Ring Groove 0 03 0 08 0 13 Clearance 0 001 0 003 0 005 Second Compression Ring to Ring 0 03 0 08 0 13 Groove Clearance 0 001 0 003 0 005 Top Compression Ring End Gap 0 25 0 51 1 00 0 010 0 020 0 039 Second Compression Ring End Gap 0 25 0 51 1 00 0 010 0 020 0 039 Oil Ring Side Rail Gap 0 38 1 40 1 80 0 015 0 055 0 071 INTAKE VALVE Valve Stem O D 6 960 6 975 0 2740 0 2746 Valve Guide I D 7 000 7015 0 2756 0 2762 Valve Stem to Valve Guide Clearance 0 03 0 06 0 10 0 001 0 002 0 004 Valve Lash 0 15 0 25 006 0 010 Face Angle 45 INTAKE VALVE SEAT Seat Width 1 1 1 7 043
16. 212 F oil for 10 to 15 minutes and then insert the piston pin into the piston and connecting rod Insert piston pin snap rings Be sure the connecting rod machined surface is on the same side as the piston mark PISTON MARK MACHINED SURFACE FIGURE 9 26 ASSEMBLING PISTON Refer to Figure 9 27 Always install new rings when assembling the engine Old rings will not reseat properly Install the rings with the ring manufactur er s mark facing towards the top of the piston RING MANUFACTURER S MARK FIGURE 9 27 RING MARK Refer to Figure 9 28 Position rings on piston as shown Gap on top ring must face opposite of intake and exhaust valves SECOND RING GAP TOP RING SIDE RAIL FIGURE 9 28 ASSEMBLING RINGS Refer to Figure 9 29 Apply engine oil to the cylinder bore Line up the piston and connecting rod so the machined surface of the connecting rod faces to wards the camshaft 9 14 MACHINED SURFACE MUST FACE CAMSHAFT FIGURE 9 29 PISTON ORIENTATION An improperly installed piston will cause engine damage The machined side of the connecting rod must face the camshaft Refer to Figure 9 30 Use a ring compressor to in sert the piston and connecting rod into the cylinder Apply engine oil to the inside diameter of the con necting rod cap and connecting rod screws Align the machined surfaces of the connecting rod and connecting rod cap Apply oil to the connecting rod bo
17. 5 if they are worn or broken 3 Push the top of the governor arm toward the carburetor until it stops and hold it there while performing the next steps 4 Check to see that the governor spring is pulling the carburetor throttle to the wide open posi tion 5 Tighten the lock nut making sure the governor shaft rotates clockwise against the internal governor parts and tighten as specified in Sec tion 3 Assembly Torques END e GOVERNOR SHAFT 2 VIEW ier LOCK NUT 3 FIGURE 5 5 ENGINE GOVERNOR ADJUSTMENTS RECONNECTING AND RECLAMPING THE CHOKE AND THROTTLE CABLES If the engine is so equipped the choke and throttle cables are secured by a single clamp choke cable above throttle cable to a bracket at the top of the en gine Figure 5 6 If necessary reconnect and re clamp the cables as follows 1 Stop the engine and disconnect the spark plug and if so equipped the battery negative cable Accidental starting of the en gine can result in severe personal injury or death Always disconnect the spark plug and battery negative cable before re setting the engine control cables Push the choke knob in to the full open choke position and the equipment throttle lever to its lowest speed position Loosen the cable clamp at the engine bracket if necessary and hook the cable wires into the hook holes in the choke and throttle control arms if not already hooked Note that there are two hook
18. ARTER STOP us MAGNETO COIL 1 SPARK PLUG BASIC ENGINE WITH OPTIONAL KILL SWITCH STOP ke I MAGNETO COIL STOP SPARK PLUG St BASIC ENGINE WITH LEAD FOR KILL SWITCH O o O KILL SWITCH MAGNETO COIL SPARK PLUG St NOTE ENGINE WIRING SHOWN BY SOLID LINES AND CUSTOMER SUPPLIED WIRING BY DASHED LINES FIGURE 6 5 SCHEMATICS OF TYPICAL ENGINE WIRING CONNECTIONS 6 4 Section 7 Starting System Accidental starting of the engine can result in severe personal injury or death Disconnect the negative battery cable and spark plug wire before servicing the engine controls or associated equipment RECOIL STARTER Disassembly Refer to Figure 7 1 Remove the four capscrews holding the recoil assembly on the en gine Remove the recoil assembly from the blower housing Inspection Service Inspect the assembly as a unit The rope should pull out freely with spring ten sion pulling the rope back in without binding or slack When pulling the rope out the dog ears should come out of their cup and they should not be bent broken or missing Assembly Place the recoil assembly on the blower housing and rotate it so that the cord pull handle is conveniently located for starting the engine Install and tighten the four capscrews to the torque speci fied in Section 3 Assembly Torques CAP SCREW RECOIL ASSEMBLY FIGURE 7 1 RECOIL STARTER REMOVAL SOLENOID SHIFT STARTER See Section 6 Elec
19. FT FIGURE 7 4 CHECKING INTEGRITY OF ARMA TURE WINDING INSULATION Checking Integrity of Windings Refer to Figure 7 5 To check winding integrity check electrical con tinuity use an ohmmeter between pairs of commu tator segments all the way around the commutator Make sure every segment is checked Replace the armature if a winding is open high resistance at any segment COMMUTATOR ES 1872 FIGURE 7 5 CHECKING INTEGRITY OF ARMA TURE WINDINGS Motor Frame Checking Integrity of Windings Refer to Figure 7 6 Two of the four brushes are connected directly to the motor frame windings one to each pair of windings The other ends of the two pairs of wind ings are crimped directly to the motor frame grounded To check the integrity of each winding pair check continuity use an ohmmeter between its brush and the crimp on the motor frame Replace the motor frame if either winding pair is open high resistance This test will not detect if a single wind ing of a pair is open If the windings look burnt or smell bad it is recommended that the motor frame be replaced ES 1880 FIGURE 7 6 CHECKING INTEGRITY OF MOTOR FRAME WINDINGS Brushes Refer to Figure 7 7 Clean up the brushes with sand paper and measure their lengths Replace the mo tor frame brush holder and brush springs if any brush is shorter than specified Section 2 Toler ances and Clearances BRUSH ES 1881 FIGURE 7 7 MEASURING BR
20. GHTS SLEEVE RETAINER FIGURE 9 13 GOVERNOR BALANCER SHAFTS Disassembly Carefully pull each shaft out one at a time Journal Bearing Clearance Measure the journal O D of each balancer shaft and the corresponding bearing I D in the gearcase Replace the gearcase and or balancer shaft s if the clearance is not as specified in Section 2 Tolerances and Clearances Assembly Refer to Figure 9 14 Align the alignment marks on the gears The crankshaft has two alignment marks which must line up with balancer shaft 1 Balancer shaft 1 has one alignment mark which must line up with the one alignment mark on balancer shaft 2 Install each shaft one at a time CRANKSHAFT ALIGNMENT MARKS Ox BALANCER SHAFT 2 BALANCER SHAFT 1 FIGURE 9 14 BALANCER SHAFT ALIGNMENT CRANKSHAFT AND CAMSHAFT Disassembly Set the engine block on the flywheel side Pull the crankshaft out with the camshaft Remove the tappets Inspection Service Crankshaft Journal Refer to Figure 9 15 Meas ure the crankshaft journal diameter If the diameter is not as specified in Section 2 Tolerances and Clearances or is scored grind it to the next under size for which an undersize connecting rod is avail able The corner radii of the journal must be ground to 0 07 to 0 09 inch 1 8 to 2 2 mm Chamfer the oil hole circumference with an oil stone to a 0 04 to 0 06 inch 1 0 to 1 5 mm radius The journal surface must be fine finished to h
21. HO aallar RR A Service Manual E125H E140H Elite Series Toga S JL IJ va Printed U S A 965 0758 1 96 Safety Precautions Before operating the engine read the Operator s Manual and become familiar with it and the equipment Safe and efficient operation can be achieved only if the equipment is properly operated and maintained The following symbols found throughout this manual alert you to potentially dangerous conditions to the operator service per sonnel or the equipment Neda This symbol warns of immediate hazards which will result in severe personal injury or death AWARNING This symbol refers to a hazard or unsafe practice which can result in severe personal injury or death A CAUTION This symbol refers to a hazard or unsafe practice which can result in personal injury or product or property damage Fuels electrical equipment batteries exhaust gases and moving parts present potential hazards that can result in severe personal injury Take care in following these recommended procedures All local state and federal codes should be consulted and complied with AWARNING This engine is not designed or intended for use in any type of aircraft Use of this engine in aircraft can result in engine failure and cause severe personal injury or death GENERAL e Provide appropriate fire extinguishers and install them in convenient locations Use an extingui
22. Housing M6x10 7 11 5 8 PROPER TIGHTNESS WITHOUT DANGER OF Bolt M8x16 11 16 8 12 STRIPPING THREADS ALL THREADS MUST BE CLEAN AND RUST FREE LIGHTLY OIL ALL Governor Arm Nut M6 8 1 10 9 6 8 O O Flywheel Nut M18 122 138 90 102 THREADS EXCEPT ON THE SPARK PLUG Oil Fill Tube M8x20 11 16 8 12 Section 4 Troubleshooting PROBLEM Engine Does Not Start Engine Cranks Slowly Engine Stops Engine Misfires Engine Backfires Engine Overheats Governor Hunts Black Exhaust Blue Exhaust Burned Valves Connecting Rod Wear Cylinder Wear High Oil Pressure Low Oil Pressure Mechanical Noise Piston Wear Bearing Wear Low Compression Ring Wear Sticking Valves PROBABLE CAUSE STARTING SYSTEM Battery Connections Poor Battery Low or Discharged Starter Faulty Starter Solenoid Faulty IGNITION SYSTEM Spark Plug Gap Wrong Magneto Coil Faulty Spark Plug Wires Faulty Magneto Gap Wrong FUEL SYSTEM Fuel Tank Empty Fuel Mixture Too Lean Fuel Mixture Too Rich Engine Flooded Fuel Quality Poor Carburetor Dirty Air Cleaner Dirty Fuel Filter Dirty Fuel Pump Defective INTERNAL ENGINE Valve Clearance Wrong Valve Spring Broken
23. IPUMD gt pesares coges aaa daa peta dana eeeh 5 4 E A e Ine 5 6 Reconnecting and Reclamping the Choke and Throttle Cables o ooooooooooo 5 7 Engine Speed Adjustments 0 ccc cc eee nent nee ene eee 5 8 Air Cleaner Maintenance 5 9 SECTION 6 ELECTRICAL SYSTEM visos owe hse Pech 00 nn u EE bar eee be REE a ac dado ws 6 1 NT II EI ETS EE 6 1 Te VDC Output System an ee rear ono tal dened ead dae 6 2 WINING GONMCCHONS sacs prd eut EE eR DUIS te PS ee qued quad made eda esq d eat 6 3 SECTION 7 STARTING SYSTEM coococco hrs 7 1 o s cases eae eres Goats ccd ce ee ee NS oe ae eke Wee eo LIS bee SE TEST ES 7 1 Solenoid Shit Starter uas ass ae wie d aki tekei Rete xoa qa a E ee Varo re an Ge aden ain ede wi eee 7 1 SECTION 8 LUBRICATION SYSTEM 0 sra 8 1 Checking Oil PICSSUIC 22220 en anna ae cease ees ecee cee R ER R KAE ee eat 8 1 OINPUMD ae es shane nee ae ae ee Etico ee Senate ete oo ab 8 2 Oil Pressure Relief Valve 0 0 ehh hrs 8 3 SECTION 9 ENGINE BLOCK ASSEMBLY 0 ccc eh 9 1 Cylinder Compression Test 2a apice e we te ae ipn rare waren ara aces har 9 1 So ML ae Ba ae en a a Eee 9 1 Value ROCKET COVEI 452 nennen rare see E abe anne daten iq n dE IE 9 1 Adjusing Valve Lash C tees a uate ia ra a av 9 1 Valve Rocker AIMS coronar ce a beck dE REN a PX Ga pes PERI eR E REIR UE Ex 9 2 Valve Pushrods and Tappets o oc ococo hrs 9 2 2 o PPP ooo EE
24. LEANER ASSEMBLY 5 9 5 10 section 6 Electrical System IGNITION SYSTEM Spark Plug See Periodic Maintenance in the Operator s Manual for scheduled spark plug inspection and replace ment See Section 2 Tolerances and Clearances for spark plug gap Figure 6 1 Clean the area around the plug before removing it Never assemble a cold spark plug into a hot cylinder head because the plug will get too tight when the en gine cools down To prevent crossthreading the spark plug always thread it in by hand until it seats If the spark plug is being reused tighten it with a wrench an additional 1 4 turn If the spark plug is new tighten it an additional 3 8 to 1 2 turn If you have a torque wrench tighten it to 20 Ibs ft 26 N m FIGURE 6 1 SPARK PLUG GAP Magneto These engines use a magneto consisting of a sta tionary coil and flywheel magnet to fire the spark plug Figures 6 2 and 6 3 The primary winding of the coil has a grounding terminal for connecting a shutoff kill switch Figure 6 5 Ignition timing is de termined by the angular relationship of the flywheel magnet to the shaft keyway and is not adjustable Table 1 1 Section 1 Introduction Gasoline is highly flammable and can cause severe personal injury or death Make certain that no gasoline or other flammable fumes are present during ignition testing Electrical shock can cause severe personal injury or death Do not touch the igni tion components
25. Remove all pits and groves on the valve face removing as little material as possible A margin of at least 0 030 inch 0 8 mm is required for strength and good heat dissipation If the end of the valve stem is worn true it up square with the stem using the refacer wheel of the valve grinding ma chine If the valve is warped a knife edge will form Make sure the valve is being held properly in the d 45 grinder chuck Replace a valve that cannot be refin ished properly WARPED VALVE WITH KNIFE EDGE KNIFE EDGE FIGURE 9 9 VALVE SEAT CUTTER Ir Gf GOOD MARGIN ol MINIMUM 0 8 mm FIGURE 9 8 VALVE HEAD MARGIN POOR SEATING Valve Seat Refer to Figures 9 9 and 9 10 Clean the valve seat and measure the seat width Apply red lead to the new or refinished valve face and ro tate it against the valve seat to check for pits and groves in the seat and for proper valve seating Use a 45 valve seat cutter to remove all pits and groves in the seat and if the valve guide was replaced to PROPER SEATING make the valve guide bore and valve seat concen SPECIFIED tric Relieve the face of the seat with a 15 valve seat SEAT WIDTH cutter if necessary to obtain the specified seat width and to seat the contact area in the middle third eee of the valve face It may be necessary to alternate cuts between the 45 and 15 cutters to seat the valve properly Replace the cylinder h
26. THER RUBBER SEAL MOUNTING SCREWS CARBURETOR SUPPORT ator adjustments and repairs have been performed and 2 that the carburetor is actually malfunctioning Carburetor Removal Refer to Figure 5 1 Remove the air cleaner assem bly Disconnect the governor linkage fuel line throt tle linkage and choke control linkage Remove the carburetor assembly from the intake elbow Carburetor Installation Install the carburetor assembly on the intake elbow Tighten the through bolts as specified in Section 3 Assembly Torques Connect choke control linkage throttle linkage fuel line and governor linkage Make sure the breather tube and rubber seal are installed properly Install the air cleaner assembly as instructed in this section Always use new gas kets when installing a carburetor Instructions for control cable and speed adjust ments follow in this section AIR CLEANER GASKET INTAKE ELBOW CARBURETOR ASSEMBLY FIGURE 5 1 CARBURETOR ASSEMBLY CARBURETOR BEGINNING SPEC C Carburetor Replacement Other than replacing the carburetor main fuel jet fixed type with the optional high altitude jet Fig ure 5 2 fuel mixture adjustments should not be at tempted Nor should the carburetor be overhauled Instead a malfunctioning carburetor should be re placed See CARBURETOR REMOVAL INSTAL LATION in this section Carburetor High Altitude Jet Optional If the engine is operated at an altitude ab
27. URING PISTON PIN DIAMETER Connecting Rod Piston Pin Bore Diameter Re fer to Figure 9 24 Measure the connecting rod pis ton pin bore diameter with an inside micrometer Re place the connecting rod if the diameter is not as specified Section 2 Tolerances and Clearances CONNECTING ROD SMALL END FIGURE 9 24 MEASURING CONNECTING ROD PIS TON PIN BORE Connecting Rod To Crankshaft Journal Oil Clearance Refer to Figure 9 25 Check oil clear ance whether reusing the old connecting rod or a new undersized rod with a reground crank journal Either use Plasti gage or measure the connecting rod bore at the locations indicated the cap bolts must be torqued to specifications and subtract the crank journal diameter If the clearance is greater than specified Section 2 Tolerances and Clear ances it will be necessary to grind the journal to the next undersize and obtain a matching undersized connecting rod If there is not enough clearance ei ther the crank journal diameter is wrong or the con necting rod is of the wrong undersize MEASURE AT THESE POINTS FIGURE 9 25 MEASURING CONNECTING ROD CRANK BORE Connecting Rod Side Clearance Assemble the connecting rod to the crankshaft and measure the side to side clearance of the connecting rod on the crankshaft Replace the connecting rod if the clear ance is not as specified Section 2 Tolerances and Clearances Assembly Refer to Figure 9 26 Immerse the piston in
28. USH LENGTH Commutator Commutator Refer to Figure 7 8 Clean the com mutator surface with sandpaper and measure the outside diameter at several locations around the commutator Turn the commutator in a lathe if the differences in measurements are greater than spe cified Section 2 Tolerances and Clearances Re place the armature assembly if the commutator can not be cleaned up and still meet the specified diam eter COMMUTATOR ES 1878 FIGURE 7 8 MEASURING COMMUTATOR O D Commutator Mica Refer to Figure 7 9 Use a saw blade to undercut the commutator mica if the under cut is less than specified Section 2 Tolerances and Clearances and chamfer the segment edges SEGMENT EDGES MICA UNDERCUT DEPTH oe SAW BLADE er ES 1879 FIGURE 7 9 MICA UNDERCUT DEPTH Pinion Inspection Service Refer to Figure 7 10 Replace the pinion assembly if the pinion teeth and armature shaft splines are worn or damaged Check the over running clutch by rotating the pinion clockwise and counterclockwise Replace the pinion assembly if it does not turn smoothly counterclockwise or lock clockwise Cleaning the pinion over running clutch in liquid cleaning solution will result in starter damage PINION FIGURE 7 10 CHECKING OPERATION OF THE PIN ION OVER RUNNING CLUTCH Armature Shaft Bushings Refer to Figure 7 11 Measure the inside diameters of the bushings in the starter drive housing and end bell and
29. Valve or Valve Seal Leaking Piston Rings Worn or Broken Bearing Clearance Wrong COOLING SYSTEM Air Circulation Poor Cylinder Cooling Fins Dirty Head Gasket Blown LUBRICATING SYSTEM Oil Level Too Low Oil or Oil Filter Dirty Oil Viscosity Too Low or Diluted Oil Viscosity Too High Oil Gauge Faulty Relief Valve Stuck Oil Pump Faulty THROTTLE GOVERNOR Linkage Out of Adjustment Linkage Worn or Disconnected Linkage Binding Governor Assembled Wrong 4 1 4 2 Section 5 Fuel System Improper service or replacement of parts can result in severe personal injury and equipment damage Service personnel must be qualified to perform electrical and mechanical service Accidental starting of the engine can result in severe personal injury or death Disconnect the negative battery cable and spark plug wire before servicing the engine controls or associated equipment Ignition of fuel can result in severe personal injury or death Do not smoke or allow any spark pilot light or arcing switch or equip ment near the fuel system or in areas with shared ventilation Provide adequate ventilation when working on the fuel system CARBURETOR REMOVAL INSTALLATION Before replacing or overhauling a carburetor make certain 1 that all other necessary engine and gener BREA
30. all machined surfaces and threaded holes Carefully remove any nicks or burrs from machined surfaces Clean out tapped holes and clean up any damaged threads 3 Check the top of the block for flatness with a straight edge and a feeler gauge Cylinder Bore Inspection Inspect the cylinder bore for scuffing scratches wear and scoring If the cylinder bore is scuffed scratched worn or scored rebore the cylinder to the next oversize If the bore looks good and there are no scuff marks check the bore for wear or out of roundness using a cylinder bore gauge telescopic gauge or inside mi crometer Figure 9 31 Measure the bore at four locations top and bottom of piston ring travel paral lel and perpendicular to the axis of the crankshaft Record and analyze the measurements as follows 1 Measure and record as A the cylinder bore di ameter parallel to crankshaft near the top of cylinder bore 2 Measure and record as B cylinder bore di ameter parallel to crankshaft at the bottom of piston travel 3 Measure and record as C cylinder bore di ameter perpendicular to crankshaft near the top of cylinder bore 4 Measure and record as D cylinder bore di ameter perpendicular to crankshaft at the bot tom of piston travel 5 The differences between A and B and be tween C and D indicate cylinder taper If cyl inder taper exceeds that specified in Section 2 Tolerances and
31. alve rocker cover rocker arm assembly and spark plug Pull out the push rods Remove the remaining cylinder head bolts and remove the cylinder head and head gas ket Assembly The cylinder head can be damaged by over tightening the head bolts Use a torque wrench Install a new cylinder head gasket Position the cyl ROCKER ARM ASSEMBLY inder head on the engine and position the rocker RETAINING BOLT arms bolts and washers as shown Make sure the pushrods are properly installed in their tappets and rocker arms Tighten the cylinder head bolts in the numbered sequence as specified in Section 3 As sembly Torques Retorque bolts 2 and 4 after all bolts have been torqued Adjust valve lash and re place the valve rocker cover as instructed in this section FIGURE 9 3 CYLINDER HEAD BOLTS NUMBERS INDICATE CYLINDER HEAD BOLT TORQUE SEQUENCE 9 3 VALVES The engine is of the overhead valve design Figure 9 4 A properly functioning valve system is essen tial for top engine performance Disassembly Remove the rocker arm assembly and the cylinder head from the engine as instructed in this section Compress the valve springs and pull out the valve VALVE LOCKS MO P sis SPRING 7 eye P Abo EXHAUST VALVE SHIELD a VALVE SPRING RETAINER locks Remove the valve spring retainers valve springs washer shield on exhaust valve only and valves Reassembly After cleaning inspection and service app
32. at is malfunc tioning Remove the solenoid mounting nuts and disconnect the connecting lead to the motor Re move the solenoid by sliding it up to disconnect the shift fork If the motor is the part that is malfunction ing continue by removing the two motor through PINION SHIFT FORK DRIVE HOUSING MOTOR FRAME BRUSHES bolts Before loosening the through bolts however scratch register lines on the drive housing motor frame and end bell so that these parts can be easily reassembled the same way relative to each other While removing the motor end bell be prepared to catch the brush springs which tend to spring loose Remove the brush insulating barrier brush springs and brush holder Separate the motor frame from the drive housing and then withdraw the shift fork and armature Assembly Assembly is the reverse of disassem bly Apply grease to the shift fork hinge and prongs and the splines on the armature shaft THROUGH BOLTS SOLENOID ARMATURE END BELL v6 BRUSH INSULATING BARRIER FIGURE 7 3 SOLENOID SHIFT STARTER 7 2 Armature Checking Integrity of Winding Insulation Refer to Figure 7 4 To check winding insulation integrity check electrical resistance use an ohmmeter be tween any commutator segment and the armature core and again between the segment and the arma ture shaft Replace the armature if the meter does not indicate high infinite resistance COMMUTATOR ARMATURE SHA
33. connect a gravity supply fuel system directly to the carburetor Replace the fuel pump as instructed in this section if the problem is eliminated by direct gravity feed If not service the carburetor as instructed in this sec tion 5 4 Fuel Pump Removal Replace a defective fuel pump assembly as follows 1 d Close the fuel shutoff valve Place a drip pan under the fuel pump and car buretor to collect fuel Disconnect the starting battery if equipped Disconnect the negative cable first to re duce the risk of arcing Remove the air cleaner cover and air filter assembly Loosen the screws that secure the fuel pump to the air cleaner pan assembly It may be neces PULSE HOSE sary to loosen the air cleaner pan mounting screws to gain access to the fuel pump 6 Disconnect the hoses and remove the pump Fuel Pump Installation Installation is the reverse of removal Replace any damaged or deteriorated fuel lines Tighten all mounting hardware to that specified in Section 3 Assembly Torques If it was necessary to loosen the air cleaner pan mounting screws to remove the pump Step 5 it will be necessary to reposition the governor arm on its shaft and to readjust the engine idle speeds See GOVERNOR ARM and ENGINE SPEED ADJUST MENTS in this section OUTLET FUEL INLET FUEL HOSE FIGURE 5 4 IMPULSE FUEL PUMP GOVERNOR ARM For top performance it is essential that the governor arm
34. d 4 Remove the muffler fuel tank chaff screen blower housing cylinder shroud etc 5 Remove the air cleaner assembly carburetor and air deflector 6 Remove the magneto coil 7 Remove the flywheel use a puller and the al ternator stator 8 Remove all accessories such as oil filter starter intake manifold exhaust manifold etc 9 Remove the cylinder head assembly 10 Remove the gearcase Note that the four shafts Supported inside the gearcase have end play shims which may stay on their shafts or come off with the gearcase Locate each shim right away and identify it or wire it to its shaft so that it can be reinstalled on its shaft 11 Remove the balancer shaft assemblies 12 Remove the connecting rod piston assembly 13 Remove the crankshaft and camshaft 14 Remove the valve tappets 15 Remove the governor assembly Keep all parts in their respective orders Keep valve assemblies together Analyze the reasons for parts failure Suggested Assembly Procedure Engine assembly is normally the reverse of disas sembly See Section 2 Tolerances and Clearances Use a torque wrench Coat the internal engine parts with oil as they are assembled After the internal en gine parts are assembled the engine should turn over by hand freely Use only genuine Onan parts and special tools when reassembling the engine 1 Install the valve tappets crankshaft and cam shaft Install the connecting rod pist
35. during testing 6 1 Ignition Spark Check If the spark plug has been serviced or replaced but the ignition system still ap pears to be the cause of the problem see Section 4 Troubleshooting perform an ignition spark check by disconnecting the spark plug cable from the spark plug do not remove the plug and connecting it to a test plug If you do not have a test plug use a new plug of the same type Ground the side elec trode of the test plug to the engine block crank the engine and observe the test plug Do not touch the plug or plug wire during testing e Good Spark The ignition system is not the problem e Weak Spark Check and readjust the magne to air gap as instructed in this section Replace the magneto coil assembly if the spark plug cable and connector are not in good condition e No Spark First check to see that e he grounding lead is not damaged or being pinched see Figure 6 5 e The stop kill switch is connected prop erly e The low oil pressure cutoff switch is func tioning properly Then if there is still no spark and the grounding terminal is not being grounded replace the magneto coil assembly SPARK PLUG CABLE TERMINAL CONNECTOR AND BOOT GROUNDING TERMINAL SHUTOFF FIGURE 6 2 MAGNETO COIL ASSEMBLY Magneto Air Gap Measure the air gap between the core of the magneto coil and flywheel magnet Figure 6 3 If necessary loosen the magneto coil mounting screws and
36. e 35 psi Do not use wire or other objects for cleaning passages this may damage critical passages Replace the float if cracked damaged or if it con tains fuel Inspect the idle adjustment needle Replace if it s bent worn or damaged in any way Check the choke and throttle shafts for excessive play in the bore This condition may necessitate re placement of the carburetor Assembly Overtightening the mixture adjust ment screw will cause carburetor damage Turn mixture adjustment screw in only until light ten sion can be felt Install idle adjust screw Turn screw in until a LIGHT tension is felt Turn the screw out 2 turns Install the main jet Install the float valve in the float Turn the carburetor upside down and install the float valve in the carburetor Slide float pin into passage in carburetor and float Install float chamber and gasket on carburetor by screwing in chamber set plug and gasket into carburetor CO Adjustment If a CO Carbon Monoxide meter is available ad just the idle mixture screw to provide 596 to 6 CO at 3300 rpm with no load on the engine If a meter is not available set the idle mixture screw at 2 turns out IDLE ADJUSTMENT CHAMBER WASHER ee CHAMBER SET PLUG pr di FIGURE 5 3 CARBURETOR COMPONENTS PRIOR TO SPEC C IMPULSE FUEL PUMP The engine may be equipped with an impulse type fuel pump which has a spring loaded diaphragm op erated by crankcase p
37. e shims on their original shafts Figure 9 12 Use Plasti gage to check shaft end clearnce whenever a gearcase crankshaft camshaft or a balancer shaft is replaced and obtain the shims necessary to meet the end clearance spe cified in Section 2 Tolerances and Clearances Apply grease to the lip of the crankshaft oil seal and make sure it is not damaged when installing the gearcase Be sure the oil pump shaft lines up with the slot on the balancer shaft Tighten the gearcase mounting bolts in a clockwise pattern to the torque specified in Section 3 Assembly Torques Torque the bolt first torqued once more CAMSHAFT SHIM CRANKSHAFT BALANCER SHAFT SHIMS CT 1126 FIGURE 9 12 SHAFT END CLEARANCE SHIM LOCATIONS GOVERNOR With the gearcase removed the governor can be in spected or disassembled for service The governor assembly must spin freely on the center pin without excessive looseness or wobble Sleeve tip wear is the most common cause of governor failure Check for flat spots on the sleeve tip If the governor sleeve gear or flyweights are worn or damaged re place them To disassemble pull the governor gear assembly off the mounting shaft Figure 9 13 To assemble install the washer gear assembly and retainer onto the shaft Thread the sleeve between the flyweights and push the assembly onto the shaft See inset drawing Figure 9 13 for position of flyweight and sleeve RETAINER INS a FLYWEI
38. ead if there is insufficient valve seat material left to clean it up and SEATN properly seat the valve SEAT CONTACT AREA IN Lapping compound is not recommended for seating MIDDLE THIRD OF VALVE FACE valves If it is used thoroughly flush the cylinder head with soap and water to remove every trace of the abrasive material so that it will not enter the en gine and cause wear FIGURE 9 10 VALVE SEATING Valve Springs See Figure 9 11 Check spring free height squareness end wear and open valve spring tension Check the valve spring retainers for wear also if the spring ends are worn Check spring height A by placing the spring on a flat surface next to a square Check squareness by rotating the spring against the square The spring is not consid ered square if B exceeds 1 5 mm 0 06 inch Check open valve spring tension using an accurate valve spring tester Replace a valve spring that is weak broken worn or not square FIGURE 9 11 MEASURING VALVE SPRING HEIGHT AND SQUARENESS ENGINE DISASSEMBLY ASSEMBLY When complete engine disassembly is necessary first remove all complete subassemblies Individual subassemblies such as the carburetor can be disas sembled and repaired at another time Suggested Disassembly Order 1 Drain crankcase oll 2 Disconnect all fuel exhaust and electric lines 3 Remove the engine from its mountings and place it on a suitable bench or work stan
39. et and opens the exhaust valve momentarily to release compression and make starting easier 3 As the engine speeds up the flyweight is forced outward by centrifugal force and the decompression pin moves down so that it no longer opens the exhaust valve 4 When the engine is stopped engine speed drops and the flyweight pulls in and the decom pression pin moves up The pin opens the exhaust valve again releasing compression The most common problem with this system is a faulty spring The spring may be too long or it may not be connected A spring that is too long will re duce the decompression cutoff speed Make sure the spring is properly attached if a problem with the cutoff speed is suspected replace the spring ENGINE START POSITION CAM GEAR TAPPET FLYWEIGHT CAMSHAFT 22 SPRING ENGINE RUNNING POSITION CT 1121s FIGURE 9 18 COMPRESSION RELEASE SYSTEM 9 11 PISTON CONNECTING ROD Disassembly and Inspection Use a ridge reamer to remove the ridge at the top of the cylinder so as not to dam age the piston when withdrawing it Removing Piston and Connecting Rod Refer to Figure 9 19 Remove the connecting rod cap turn the crankshaft so the piston is at top dead center and pull the piston and connecting rod out the top of the cylinder Make a mark on the piston on the same side as the machined surface on the connecting rod MARK N MACHINED SURFACE FIGURE 9 19 PISTON MARKING Inspecting Pis
40. ew 21 96 kPa 3 14 psi Worn 28 kPa 4 psi Ignition Timing not adjustable 23 BTDC In this manual the flywheel end is considered the front of the engine Right and left sides are deter mined by viewing the engine from the front Section 2 Tolerances and Clearances and Sec tion 3 Assembly Torques provide information nec essary for proper reassembly of the engine They are referenced throughout the manual Section 4 Troubleshooting provides a way to sys tematically locate engine problems Section 5 Fuel System Section 6 Electrical Sys tem Section 7 Starting System and Section 8 Lu brication System cover service of major subsys tems of the engine Section 9 Engine Block Assembly covers the com plete overhaul of the engine block assembly See the separate Operator s Manual for engine op eration maintenance and storage and for fuel and lubricating oil recommendations See the separate Parts Manual for part identification numbers and required quantities and for exploded views of the engine subassemblies Genuine Onan replacement parts are recommended for best results When ordering parts always give the complete model and serial numbers appearing on the engine nameplate See Table 1 2 for a break down of the engine model number TABLE 1 2 ENGINE MODEL NUMBER m 140 H N 11152 A 1 2 3 4 5 6 1 Model Letter 2 Rated Power 140 designates
41. hen performing maintenance on the foam wrap per only do not remove the inner air cleaner cover Remove and wash the foam wrapper in water and detergent Squeeze the foam wrapper dry like a sponge Rinse with clean water and allow it to dry Coat the wrapper evenly with one tablespoon 14 grams of SAE 30 engine oil Knead the oil into the wrapper and wring out the excess oil MOUNTING NUT QUARTER TURN FASTENER Failure to adequately wring out excess oil from the wrapper may cause a drop in engine power due to a restriction of inlet air Install the foam wrapper over the paper air cleaner element by stretching it over the inner cover Com pletely cover all exposed paper pleats Replace the foam wrapper when it becomes torn or stretched Air Cleaner Element Replacement To keep anything from entering the carburetor and engine while the air cleaner element is off pull the choke knob to the full choke position to close the choke plate in the carburetor Remove the outer cover and wipe away loose dust and debris from the air cleaner assembly Remove the mounting nut in ner cover and air cleaner element Wipe off dust and debris from the air cleaner base Install the new paper element and secure it with the inner cover and mounting nut Tighten the nut 1 1 2 turns after seating it on the cover Reinstall the foam wrapper and outer cover AIR CLEANER ELEMENT FOAM WRAPPER AIR CLEANER ASSEMBLY BASE FIGURE 5 8 AIR C
42. hest speed position Loosen the high idle speed stop plate clamping screw and rotate the stop plate while holding the throttle control arm against it until the speci fied high idle speed is obtained and then retigh ten the clamping screw On lever controlled en gines adjust the lever stop screw while holding the throttle lever up against it until the specified high idle speed is obtained 4 Check for full smooth movement of the throttle control arm lever between its two stop posi tions LEVER CONTROLLED ENGINES THROTTLE LEVER high idle position CHOKE LEVER full open position HIGH IDLE SPEED STOP SCREW Note Do not loosen the high idle speed stop plate stop screw unless you are a qualified mechanic and have an accurate tachometer to set the high idle speed in accordance with the equipment manufacturer s specifications FIGURE 5 7 SPEED ADJUSTMENTS AIR CLEANER MAINTENANCE Refer to Periodic Maintenance in the Operator s Manual for scheduled foam wrapper maintenance and air cleaner element replacement Refer to Fig ure 5 8 Outer Cover To remove the outer cover rotate the quarter turn fastener counterclockwise to its vertical position Then lift the cover and remove it To reinstall the out er cover place the cover over the base push the quarter turn fastener in and then rotate it clockwise to its horizontal position Foam Wrapper Maintenance W
43. igher than 6 uin 0 4 um Ra OIL HOLE CRANKSHAFT JOURNAL RADII FIGURE 9 15 CRANKSHAFT JOURNAL Camshaft Lobe Height Refer to Figure 9 16 Measure the height of each cam at its highest point lf measurements are not as specified in Section 2 Tolerances and Clearances replace the camshaft CAMSHAFT P NS cm FIGURE 9 16 MEASURING CAMSHAFT LOBE HEIGHT Camshaft Journal Bearing Clearance Measure the camshaft journal bearing O D and the corre sponding bearing l D in the gearcase Replace the gearcase and or the camshaft if the clearance is not as specified in Section 2 Tolerances and Clear ances Assembly Install the tappets in the block Apply engine oil to the governor lever shaft Apply grease to the oil seal lip and be careful not to roll the seal when inserting the crankshaft Line up the crankshaft and camshaft timing marks and insert both into the block at the same time Refer to Figure 9 17 TIMING MARKS CAMSHAFT CRANKSHAFT FIGURE 9 17 CRANKSHAFT AND CAMSHAFT TIM ING MARKS 9 10 COMPRESSION RELEASE SYSTEM This engine has a compression release system that decreases the amount of effort required to start the engine and reduces engine run on when stopping Figure 9 18 The system works as follows 1 As the engine is started a spring holds in the flyweight which in turn pushes a decompres sion pin upwards 2 The decompression pin pushes up on the exhaust tapp
44. l combustion engine fuels are highly flammable e Fuelline must be of steel piping adequately secured and free from leaks Piping at the engine should be approved flexible line Do not use copper piping for flexible lines as copper will work harden and become brittle enough to break e Be sure all fuel supplies have a positive shutoff valve e Benzene and lead found in some gasoline have been identified by some state and federal agencies as causing cancer or reproductive toxicity When checking draining or adding gasoline take care not to ingest breathe the fumes or contact gasoline EXHAUST SYSTEM e Exhaust products of any internal combustion engine are toxic and can cause injury or death if inhaled When operating the engine in a confined area make sure the ventilation system is operating properly e DO NOT use exhaust gases to heat a compartment e Make sure that your exhaust system is free of leaks Make sure that exhaust manifolds are secure and are not warped by bolts unevenly torqued EXHAUST GAS IS DEADLY Exhaust gases contain carbon monoxide a poisonous gas that can cause unconsciousness and death It is an odorless and colorless gas formed during combustion of hydrocarbon fuels Symptoms of carbon monoxide poisoning are e Dizziness e Vomiting e Headache e Muscular Twitching e Weakness and Sleepiness e Throbbing in Temples If you experience any of these symptoms get out into fresh air immediately shu
45. less than that specified in Table 1 1 Section 1 Introduction Low oil pressure may indi cate e low oil level e Oil of the wrong viscosity e Oil diluted by fuel e Clogged oil filter e defective oil pump e Clogged oil gallery e Worn crank journal connecting rod e defective relief valve or spring Determine the cause of the low oil pressure and per form the necessary service INSTALL OIL PRESSURE GAUGE HERE FIGURE 8 2 OIL PRESSURE CHECK OIL PUMP Disassembly Refer to Figure 8 3 Remove the capscrews holding the oil pump cover to the gearcase Separate the in ner and outer rotor FIGURE 8 4 MEASURING ROTOR LOBE COMPO NENTS Outer Rotor and Pump Body Clearance Refer to Figure 8 5 Measure the clearance between the outer rotor and the pump body with a feeler gauge If the clearance is not as specified in Section 2 Toler ances and Clearances replace the oil pump FIGURE 8 3 OIL PUMP DISASSEMBLY Inspection Service Rotor Lobe Clearance Refer to Figure 8 4 Meas ure the clearance between the inner rotor lobes and the outer rotor lobes with a feeler gauge If the clear ance is not as specified in Section 2 Tolerances and FIGURE 8 5 MEASURING OUTER ROTOR TO Clearances replace the oil pump PUMP BODY CLEARANCE Rotor and Cover Clearance Refer to Figure 8 6 Put a strip of plastigauge on the rotor face Install the pump cover and tighten the screw
46. lt until all bolts Cover Bolts are tightened Torque the first bolt twice Spark Plug M14 1 25 24 30 18 22 3 1 DESCRIPTION BOLT METRIC ENGLISH INSTRUCTIONS SIZE N m LB FT Pulse Pump to Air 1 7 2 1 Cleaner Pan 10 EAD 20 25 Ib in Intake Elbow to Cylinder Haad M8 x 50 11 16 8 12 Air Cleaner Pan to Cylinder Block M8 x 16 11 16 8 12 lt Tighten twice 1 2 1 E to varburetorto Intake Er Mex 85 10 15 7 11 lt Tighten twice 1 2 1 0 ul Air Cleaner Wingnut 1 4 20 Tighten 6 to 8 clicks after seating air cleaner lt Control Plate Screws M5 x 16 30 7 9 5 5 7 nn M5 x 10 2 7 5 4 2 4 CYLINDER HEAD TORQUE SEQUENCE Fuel Line Hold Down 1 1 5 Screw 51010 Ache 12 18 Ib in Throttle Cable Clamp 1 1 5 Screw nione Los 12 18 Ib in Voltage Regulator 5 5 6 _ Screws ve 2009 PRSE 60 72 Ib in 3 Starter Bolts M8 x 40 16 22 12 16 oc Alternator Stator E Serawe M6 x 25 10 15 7 11 Ignition Coil Bolt M6 x 30 10 15 7 11 Connector Wire Har 1 1 5 ness to Blower Housing MAXIA KAA 12 18 Ib in Blower Housing Bolts M6 x 20 7 11 5 8 Blower Housing to Man ifold Bolt M6 x 14 10 15 7 11 d Starter Cover Bolts 3 8 x 16 25 35 18 26 F Chaff Screen Bolts M6 x 10 7 11 5 8 1 1 5 E Stationary Guard Bolts M6 x 20 1 1 2 12 18 Ib in LLI Recoil Starter Cup I _ z in crew 1 4 20 7 11 5 8 Cylinder Air
47. lts and tighten them to the torque specified in Section 3 Assembly Torques MACHINED SURFACE MUST FACE CAMSHAFT FIGURE 9 30 CONNECTING ROD AND CAP ALIGN MENT ENGINE BLOCK The engine block is the main support for all other ba sic engine parts and subassemblies Cleaning After removing the cylinder head gearcase piston crankshaft etc inspect the block for cracks and wear If block is still serviceable prepare it for clean ing as follows 1 Scrape all old gasket material from block Remove the oil by pass Lubrication to allow cleaning solution to enter the oil passages 2 Remove grease and scale from the engine block by agitating it in a bath of commercial cleaning solution or hot soapy solution 3 Rinse the block in clean hot water to remove the cleaning solution Inspection General Inspection For Cracks And Damage Thoroughly inspect the block for any condition that would make it unfit for further use This inspection must be made after all parts and subassemblies have been removed and the block has been cleaned and dried 1 Minute cracks can be detected by coating the suspected area with a mixture of 25 percent kerosene and 75 percent light motor oil Wipe the part dry and immediately apply a coating of zinc oxide white lead dissolved in wood alco hol If cracks are present the white coating will become discolored at the defective area Al ways replace a cracked engine block 2 Inspect
48. ly engine oil to the valves and valve guides and reassemble the valves in the reverse order in which they were disassembled INTAKE SEAL WASHER lt STOPPER o VALVE GUIDE CYLINDER HEAD VALVE SEATS not removable or replacable oi INTAKE VALVE EXHAUST VALVE FIGURE 9 4 VALVE ASSEMBLY Inspection and Service Valve Stem and Valve Guide Clearance Refer to Figures 9 5 and 9 6 Remove carbon from the valve stems and guides Measure the valve stem outside diameter at six locations Measure the valve guide bore at three locations Calculate the clearance If the clearance is not as specified in Section 2 Toler ances and Clearances replace the guide or guide and valve FIGURE 9 5 MEASURING VALVE STEM DIAMETER REMOVAL VALVE GUIDE FIGURE 9 6 MEASURING VALVE GUIDE BORE Valve Guide Replacement Refer to Figure 9 7 Press out the valve guide using a special valve guide replacing tool Apply engine oil to the new valve guide install the stopper ring on the guide and press the guide in until the stopper ring contacts the cylinder head Driving out old valve guides can cause guide and guide bore damage Do not strike guide or guide bores with driver during re moval INSTALLATION STOPPER RING CYLINDER HEAD VALVE GUIDE STOPPER RING FIGURE 9 7 REPLACING VALVE GUIDE Valve Face Refer to Figure 9 8 Refinish used valves with a valve grinding machine The specified face angle is 45
49. obable cause is loss of magnetism WIRING CONNECTIONS to Table 6 1 for test specifications Use a multi me ter Simpson 270 when testing the alternator Figure 6 5 includes schematics of typical engine wiring connections 6 3 WIRING HARNESS WITH 4 PIN CONNECTOR FOR CUSTOMER CONNECTIONS 1 1 Al SS te e e Ne AS L Koa OPTIONAL CHARGING SYSTEM A2 ri o T L AMMETER 25 AFUSE Alf I ehe Md N ae ai EN Ba VOL ALT PACKARD CONNECTOR B ul BE STATOR PROVIDED ON ENGINE AC REC OPTIO S5BB BH NS ee MATING CONNECTOR IS N PACKARD 06294544 NA C A2 B M So N M G GROUND L LIGHTS OPTIONAL STARTER AS M MAGNETO Me gt CABAS MAGNETO COIL 8 BATTERY MN S START SPARK PLUG POSITION CIRCUIT MAKE b A4 ii OFF G M o S R RU B L M START B L S TYPICAL KEY SWITC KEY SWITCH ENGINE OPTIONALOIL INDAK 3H463A REVB SHOWN CONNECTOR PRESSURE SWITCH ENGINE WITH OPTIONAL START STOP SWITCH OPTIONAL CHARGING SYSTEM 25 A FUSE x Lelac p VOL ALT NG TB REG STATOR KAC REC _ d Q START SN OPTIONAL ST
50. on assembly Install the balancer shafts Install the governor assembly Install the gearcase Se 2 x X PY Install the cylinder head assembly and adjust valve lash 7 Install the accessories such as the oil filter starter intake manifold exhaust manifold etc 8 Install the alternator stator and flywheel 9 Install and gap the magneto coil 10 Install the air deflector carburetor and cleaner assembly 11 Install the cylinder shroud muffler fuel tank blower housing chaff screen etc 12 Install the engine on its mounting 13 Connect all fuel exhaust and electric lines 14 Fill the crankcase with oil Operation Start the engine and check oil pressure Run for ap proximately 15 minutes to bring engine to operating temperatures Check for oil fuel and exhaust leaks Adjust low and high idle speeds See Fuel System GEARCASE Disassembly Remove the oil pressure switch if provided located next to the oil filter Unscrew the gearcase mounting screws Tap the gearcase with a plastic hammer to remove it Do not pry it off with a screwdriver chisel etc Note where all shims come off from They may come off with the shaft or remain in the bore in the gearcase Assembly Always use a new gearcase gasket and crankshaft oil seal See BALL BEARINGS and CRANKSHAFT OIL SEALS at the end of this section for instructions on how to replace ball bearings and oil seals Install the shaft end clearanc
51. ove 5000 feet 1524 metres it is recommended that the car buretor main fuel jet be replaced with the optional high altitude jet which has a slightly smaller orifice To avoid slipping and gouging the main fuel jet use a screwdriver with a 5 16 inch 8 mm wide blade THROTTLE LEVER TAMPER RESISTANT IDLE SPEED PLUG OVER IDLE STOP SCREW MIXTURE NEEDLE OP MAIN FUEL JET BOWL FOR ACCESS TO shown enlarged THE MAIN FUEL JET REMOVE THE FLOAT FIGURE 5 2 CARBURETOR 5 2 CARBURETOR PRIOR TO SPEC C Carburetor parts are fragile and must be handled with care Never force a part when disassembling or assembling the carburetor Carburetor Disassembly Remove the chamber set plug and washer from the float chamber Figure 5 3 Remove the float cham ber and gasket Slide the float pin out from the pas sage in the carburetor Remove the float and float valve from the carburetor Remove the main jet Remove the idle adjust screw Carburetor Inspection Service Soak metal components in a carburetor cleaner Do not soak non metal parts and gaskets in carburetor cleaner Follow the cleaner manufacturer s recom mendations Clean carbon from the carburetor bore especially around the throttle and choke plates Dry out all air passages with low air pressur
52. readjust the gap as specified Section 2 Tolerances and Clearances 12 VDC OUTPUT SYSTEM The engine may be equipped to provide a 12 volt DC Direct Current output for powering equipment ac cessories and or recharging the cranking battery Figure 6 4 The system consists of a permanent magnet flywheel alternator and a solid state rectifi er voltage regulator There are two output ratings available 5 amp and 20 amp The 5 amp system has 3 magnets in the flywheel and the 20 amp sys tem 6 ALTERNATOR STATOR The flywheel must be removed for access to the al ternator stator See Section 9 Engine Block Assem bly MAGNETO FLYWHEEL MAGNET FIGURE 6 3 MEASURING MAGNETO AIR GAP 12 VDC OUTPUT RECTIFIER VOLTAGE REGULATOR O AA S ATORR LEADS PATH OF FLYWHEEL MAGNETS FLYWHEEL REMOVED FIGURE 6 4 FLYWHEEL ALTERNATOR AND VOLTAGE REGULATOR TABLE 6 1 12 VDC OUTPUT SYSTEM TEST SPECIFICATIONS VOLTAGE BATTERY REGULATOR STATOR STATOR VOLTAGE OUTPUT OUTPUT RESISTANCE 12 to 13 13 6 to 14 7 VDC VDC 12 VDC System Tests Keep the following points in mind when testing or
53. ressure pulses The fuel flow direction is marked on the cover of the pump Re place the pump if it leaks or fails to pump Ignition of fuel can result in severe personal injury or death Do not smoke or allow any spark pilot light or arcing switch or equip ment near the fuel system or in areas with shared ventilation Provide adequate ventilation when working on the fuel system Inspection Service Preliminary Checks and Service Perform the fol lowing checks and service before inspecting the fuel pump if it is suspected that fuel delivery is the prob lem causing the engine not to start or to starve for fuel under load 1 Check the fuel tank and refill it as necessary Replace the fill cap if the vent is plugged 2 Open all fuel shutoff valves if any in the fuel supply line 3 Check the engine oil level and refill as neces sary 4 Check the fuel hose for kinks pinches and leaks and service as necessary Note that dips and long runs of fuel line can lead to vapor lock in hot weather 5 Replace the fuel filter if necessary 6 Inspect the crankcase for visible oil leaks es pecially around the seal on the oil fill tube and service as necessary If the crankcase is not properly sealed the pressure pulses may be too weak to operate the fuel pump as required 7 f the gasoline in the supply tank is more than six months old dispose of it properly and refill the tank with fresh fuel See the Operator s Man
54. rotating hone 250 to 450 rpm up and down in the cylinder about 40 times per minute Thoroughly clean the engine block with soap water and clean rags A clean white rag will not become soiled when the cylinder wall is clean Solvents and gasoline are not effective in re moving the metal and abrasive particles which can cause engine wear Dry the block and coat the cylinder bore with oil Deglazing the Cylinder Bore When the cylinder bore is not out of round or ta pered beyond specifications nor scuffed or other wise worn it is necessary only to deglaze the bore so that the new rings will break in rapidly The old piston can be reused if it is not worn or fractured or otherwise unusable To deglaze the bore 1 Wipe the cylinder bore with a clean cloth that has been dipped in clean light engine oil 2 Use a brush type deglazing tool with coated bristle tips 3 Use a slow speed drill to drive the deglazing tool Move the deglazing tool up and down in the cylinder bore 10 to 12 complete strokes rap idly enough to obtain a crosshatch pattern Figure 9 32 4 Thoroughly clean the engine block with soap water and clean rags A clean white rag will not become soiled when the cylinder wall is clean Solvents and gasoline are not effective in re moving the metal and abrasive particles which can cause engine wear 5 Dry the block and coat the cylinder bore with oil Checking for Correct Piston and Ring Size To double
55. s to that specified in Section 3 Assembly Torques Remove the cover carefully and measure the width of the plastigauge with the table provided If clearance is not as speci fied in Section 2 Tolerances and Clearances re place the oil pump IS 1218 FIGURE 8 6 MEASURING ROTOR TO COVER CLEARANCE Assembly Lubricate each part with oil before reassembling Follow torques given in Section 3 Assembly Torques when tightening hardware Check the oil pressure after servicing or replacing any lubrication system component OIL PRESSURE RELIEF VALVE Disassembly Refer to Figure 8 7 The oil pressure relief valve is assembled in the gearcase and is accessible only after the gearcase has been removed from the en gine block See Section 9 Engine Block Assembly Remove the retaining ring relief valve spring and check ball RELIEF VALVE SPRING RETAINING RING IS 1215 FIGURE 8 7 OIL RELIEF VALVE COMPONENTS Inspection Service Most solvents are flammable and can cause severe personal injury or death if used improperly Follow the manufacturer s recommendations when cleaning parts Wash the components in solvent and allow to dry Inspect components for damage wear etc Re place parts as necessary Assembly Oil the check ball and oil passage in the gearcase before assembling Use a new retaining ring and drive it in down to the bottom of the passage coun terbore 8 3 8 4 Section 9 Engine Block
56. sher rated ABC by NFPA e Make sure that all fasteners on the engine are secure and accurately torqued Keep guards in position over fans driving belts etc e lf itis necessary to make adjustments while the engine is running use extreme caution when close to hot exhausts moving parts etc e Used engine oils have been identified by some state and federal agencies as causing cancer or reproductive toxicity When checking or changing engine oil take care not to ingest breathe the fumes or contact used oil e Do not work on this equipment when mentally or physically fatigued or after consuming any alcohol or drug that makes the operation of equipment unsafe BATTERIES e Before starting work on the engine disconnect batteries to prevent inadvertent starting of the engine Disconnect negative cable first e DO NOT SMOKE while servicing batteries Lead acid bat teries give off a highly explosive hydrogen gas which can be ignited by flame electrical arcing or by smoking e Verify battery polarity before connecting battery cables Connect negative cable last PROTECT AGAINST MOVING PARTS e Do not wear loose clothing in the vicinity of moving parts such as PTO shafts flywheels blowers couplings fans belts etc e Keep your hands away from moving parts FUEL SYSTEM e DO NOT fill fuel tanks while engine is running e DO NOT smoke or use an open flame in the vicinity of the engine or fuel tank Interna
57. t down the unit and do not use it until it has been inspected The best protection against carbon monoxide inhalation is proper installation and regular frequent inspections of the complete exhaust system If you notice a change in the sound or appearance of exhaust system shut the unit down immedi ately and have it inspected and repaired at once by a competent mechanic KEEP THE UNIT AND SURROUNDING AREA CLEAN e Make sure that oily rags are not left on or near the engine e Hemove all unnecessary grease and oil from the unit Accumulated grease and oil can cause overheating and subsequent engine damage and present a potential fire hazard E 8 Table of Contents TITLE Sac epe bee oon bese e rn ee eee eda es ea Der a a aa o PAGE SAFETY PRECAUTIONS coccccc eens INSIDE FRONT COVER SECTION 1 INTRODUCTION 0 0 cc eee eee eee eee eens 1 1 SECTION 2 TOLERANCES AND CLEARANCES esee 2 1 SECTION 3 ASSEMBLY TORQUES csse rrr 3 1 SECTION 4 TROUBLESHOOTING 4 uk rd ERE AUR E ae Oe osu Eden cde a a e ees Ro E e s 4 1 SECTION S FUEL SYSTEM 4 5337 3 023 id 2824 eon 7906 bon cg i d EE ORT SE E Rr e ORC 5 1 Carburetor Removal Installation 0 0 0 c eee eee I eens 5 1 Carburetor Beginning Spec C 2 ee ene nee eee een nennen nenn 5 2 Carburetor Prior to Spec C ses er epee i doit we dox hain acp ea ws em e ol edle he Meaney nw we aisha ww Hoe 5 3 IMPuISS FUG
58. ton For Wear and Fractures Refer to Figure 9 20 Remove the rings from the piston by using a ring tool Remove the piston pin snap rings and push out the piston pin Look for fractures at the piston ring lands skirts and pin bosses and for scuf fing scoring and wear Excessive piston wear near the edge of the top ring land indicates preignition Replace a piston that is worn or has fractures CAUTION Using caustic cleaning solvents and wire brushes to clean a piston can cause damage to the piston PISTON PIN PA ENS PISTON PIN SNAP RING FIGURE 9 20 PISTON ASSEMBLY Piston Ring Groove Clearance Refer to Figure 9 21 To check for ring grove wear remove carbon from the ring groves insert a new piston ring and measure the side clearance at several locations Replace the piston if the clearance is greater than specified Section 2 Tolerances and Clearances PISTON FIGURE 9 21 MEASURING RING GROOVE CLEAR ANCE 9 12 Piston Pin Bore Diameter Refer to Figure 9 22 Measure the piston pin bore diameter at various places Replace the piston if the diameter is not as specified Section 2 Tolerances and Clearances PISTON PIN HOLE Xo FIGURE 9 22 MEASURING PISTON PIN BORE Piston Pin Outside Diameter Refer to Figure 9 23 Measure the piston pin outside diameter Re place the piston pin if the diameter is not as speci fied Section 2 Tolerances and Clearances PISTON PIN FIGURE 9 23 MEAS
59. trical for typical wiring connec tions at the starter solenoid Inspection Refer to Figure 7 2 Before removing a starter because the engine does not crank 1 Make sure that the battery is fully charged and that the connections are clean and tight and that the battery cables are in good condition If it is necessary to reconnect the battery connect the positive battery cable first 2 Disconnect the spark plug cable so that the en gine will not start Then bypass the start circuit with a jumper between the Start and the Battery Positive terminals on the solenoid Figure 7 2 If the engine cranks the solenoid and starter are probably okay If the engine does not crank go to Step 3 3 Bypass the starter solenoid with a jumper be tween the Motor and the Battery Positive terminals on the solenoid Figure 7 2 If the motor responds it is probably okay and it may only be necessary to replace the solenoid BATTERY POSITIVE TERMINAL A N I i N x START TERMINAL N De MOTOR TERMINAL C FIGURE 7 2 STARTER SOLENOID TERMINALS Accidental starting of the engine can result in severe personal injury or death Disconnect the negative battery cable and spark plug wire before servicing the engine controls or associated equipment Disassembly Refer to Figure 7 3 Remove the starter assembly from the engine if either the sole noid or motor appears to be the part th
60. ual for fuel recommendations The Engine Will Not Start If the engine still will not start after performing any necessary preliminary service crank the engine and then remove and in spect the spark plug If the spark plug is wet and has a strong gasoline smell the fuel pump is probably okay Check for e A fouled spark plug Clean and regap or re place a fouled spark plug Note that a fouled spark plug may indicate the need for engine service e An improperly adjusted carburetor choke See RECONNECTING AND RECLAMPING THE CHOKE AND THROTTLE CABLES in this section e A defective or improperly connected Off or Kill switch See Section 6 Electrical Sys tem If the spark plug is dry check fuel pump operation as follows e Ground the spark plug lead so that ignition sparks can not ignite the gasoline e Disconnect the fuel outlet hose to the carbu retor connect a hose at least 200 mm 8 in ches long and direct the end of the hose into a container to collect the gasoline e Crank the engine with the electric starter or the recoil starter for 20 seconds Replace the fuel pump as instructed in this section if there is no fuel flow from the pump If there is fuel flow service the carburetor as instructed in this sec tion The Engine Runs But Starves For Fuel Under Load If the engine appears to starve for fuel under load disconnect the regular fuel supply to the en gine or close the fuel shutoff valve and
61. ustments must be made using an accurate tachometer Set the low idle and high idle speeds to the values specified in the equipment Operator s Manual In the absence of such specifications it is recommended that low idle speed be adjusted to 1400 RPM and high idle speed to 3400 RPM Adjusting the engine speed to a val ue above that specified by the equipment manufacture could cause the equipment to op erate at speeds in violation of Federal and State Standards for Safety for the equipment Moving parts can cause severe per sonal injury or death Take care when measur ing engine speed with a tachometer and follow the meter instructions You must be a qualified mechanic Refer to Figure 5 7 If necessary first adjust the gov ernor arm and reconnect and adjust the choke and throttle control cables as instructed in this section CABLE CONTROLLED ENGINES HIGH IDLE SPEED STOP LN s THROTTLE CONTROL ARM i below choke control arm g ge wh LOW IDLE SPEED STOP SCREW on the carburetor Then adjust the low idle and high idle engine speeds as follows 1 Start the engine observing all of the equipment manufacturer s instructions and precautions and move the equipment engine throttle lever to its lowest speed position 2 Adjust the low idle speed stop screw on the carburetor to obtain the specified low idle speed 3 On cable controlled engines move the equip ment throttle lever to its hig
62. w until the specified lash is obtained Tighten the locknut and recheck lash ADJUSTING FIGURE 9 1 ADJUSTING VALVE LASH VALVE ROCKER ARMS Refer to Figure 9 2 Remove the snap rings and washers on the ends of the rocker arm shaft and pull off the rocker arms Determine the clearance be tween rocker arm bore and shaft by measuring the shaft diameter and the rocker arm bore If the clear ances are not as specified in Section 2 Tolerances and Clearances replace the rocker arms and or shaft Apply engine oil to the rocker arm shaft when reas sembling the rocker arms VALVE PUSHRODS AND TAPPETS Replace pushrods that are bent or that have worn ends The pushrods can be removed once the valve rocker arms have been removed Replace tappets that have rough scuffed or worn faces The tappets can be removed from inside the crankcase once the camshaft has been removed Also check the cam lobes for scuffing and height if the tappets are worn Very little wear normally takes place between tappets and the tappet bores in the block If the tappets feel loose in their bores it may be necessary to replace the block ROCKER ARM ROCKER ARM SHAFT SNAP RING FIGURE 9 2 VALVE ROCKER ARM ASSEMBLY 9 2 CYLINDER HEAD Disassembly The cylinder head can be damaged by removing it when the engine is hot above 100 F 37 C Let the engine cool down before removing the cylinder head Refer to Figure 9 3 Remove the v
63. wheel or the inlet screen and the surrounding sheet metal Then loosen the flywheel mounting nut a couple of turns and use a flywheel puller to break the flywheel free of the shaft taper Hemove the woodruff key in the crankshaft Replace the flywheel assembly if the ring gear is worn gear teeth or fan blades are missing or the al ternator magnets are weak Clean up all parts mak 9 1 ing sure the shaft taper and flywheel bore are clean and free of oil Reinstall the key in the shaft and tight en the flywheel nut to the specified torque Section 3 Assembly Torques VALVE ROCKER COVER Remove the valve rocker cover to gain access to the cylinder head bolts breather assembly valve rock er arms push rods and valves Always use a new gasket when reinstalling the cover and make sure the mating surfaces are clean and undamaged Tighten the cover bolts in a two step crisscross pat ten to the specified torque Section 3 Assembly Torques ADJUSTING VALVE LASH See Periodic Maintenance in the Operator s Manual for scheduled valve lash adjustments The engine must be at room temperature when ad justing valve lash Remove the valve rocker cover and spark plug Turn the engine over until the piston is at COMPRESSION TOP DEAD CENTER Check intake and exhaust valve lash clearance with a feeler gauge If the clearance is not as specified in Section 2 Tolerances and Clearances loosen the locknut and turn the lash adjusting scre

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