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Service And Repair Manual For Small Frame GN

1. 9 12 SECTION 4 OPTIONAL IDLE CONTROL 22 23 PURPOSE AND SCOPE OF MANUAL s 8 GENERAL fi i 6 un mm i m D d f 22 SMALL FRAME ENGINES 8 OPERATING INSTRUCTIONS nee 22 LONG BLOCK 2 22 212121181151 15181 8 BELONG SAUD Re 22 ENGINE I D NUMBER SERIAL NUMBER 8 Engine RUNING u u L a 22 RNN me 10 CIKCUIIOPERAIONUAO OTTO 22 Recommended Fuels 10 IDLE CONTROL ADJUSTMENT inp ie 23 Recommended Engine 10 EE 23 Chande 10 Initial Adjustment 23 STORAGE INSTRUCTIONS uu u uu u utu teet i nes cen 10 Final AdJUSIMEN C Qu LI men pete ed cd tocum 23 TUNE UP PROCEDURE 10 11 OVERSIZE 12 SECTION 5 REWIND 5 5 24 25 EN 24 t ii i su TASTE REWIND ASSEMBLY REMOVALS os 24 AIR CLEANER 1n 14 DISASSEMBLY OLD SLE narii 25 E S 14 isis 25 Foam Pre Cleaner 102 1 14 DS SS END EY EV 25 Paper FILET 14 SECTION 6 ELECTRIC STARTERS AND BATTERIES 26 28 aS i s u TION s 26 Air Cleaner Box Installati
2. 46 VANE ER VICE 33 EE 46 C 33 OIL PICKUP ASSEMBLY a 46 REIR 33 SG 46 Valve Guides 222222222 2 34 uu T 46 Valve Tappets 34 OU PUMP A 46 47 Valve Springs errereen nn 3A Wwisegsuo E 46 INSTALLATION 34 35 lgseses 47 ADJUSTING VALVE CLEARANCE 36 CRANKSHAFT OIL SEALS uiia raza eta evo Oo 47 INSTALL ROCKER ARM COVER 36 PRESSURE VALVE 48 Weg Oc 48 SECTION 10 PISTON RINGS AND ROD 38 41 igso qe c 48 GENERAL ee 38 BREATHER ASSEMBLY Ag je gt 38 Description 48 HI N ui 38 39 INSPECTION 48 Removal from Connecting Rod 38 CRANKCASE COVER 48 50 Check Piston for 38 39 DGG 48 49 l NN 9 Inspection 49 39 49 Bisse tease eee eee errr rte 39 49 50 Ring End 40 4400 4400040 0 OPTIONAL OIL FILTER 49 CONNEC TING ROD 40 LOW OIL PRESSURE SYSTEM 49 50 ASSEMBLY AND INSTALLATION
3. Using a new gasket place the air cleaner box car buretor line up the holes and install the two phillips head screws see Figure 2 2 If reinstalling the air cleaner box with a choke style carburetor line up the holes of the car buretor and air cleaner box with the holes on the intake manifold before installing the phillips head screws see Figure 2 3 Refer to Torque Specifications on page 59 for proper torque 2 Install the cap screw in the upper part of the air cleaner box Refer to Torque Specifications on page 59 for proper torque 3 Reinstall the breather hose 4 Reinstall the choke knob units with choke type carburetor 5 Install the filters and cover as stated in the preceding sections on filter maintenance CARBURETION GENERAL Proper engine performance depends on the carburetion system The use of clean fresh fuel and a well maintained air cleaner is extremely important to engine operation as well as engine reliability and power COMMON CARBURETOR PROBLEMS Most causes of carburetor problems are related to the use of stale gummy fuel and the ingestion of dirt Prior to ser vicing any carburetor be sure to check for evidence of these conditions SECTION 2 AIR CLEANERS AND CARBURETION Gasoline that is left in the system for long periods can form gum or varnish deposits that will adversely affect carburetor operation NOTE Use of a good fuel stabilizer will minimize the formatio
4. VALVE SPRINGS Inspect the valve springs Figure 9 11 Measure the spring FREE LENGTH Also measure the spring length when a known load is applied to the spring 1 _ Figure 9 77 Valve Spring VALVE SPRING FREE LENGTH GN 190 1 910 inch 48 48 mm GN 191 2 074 inch 52 69 mm GN 220 2 074 inch 52 69 mm FORCE NEEDED TO COMPRESS SPRING TO 1 39 INCH 35 2 mm GN 190 14 8 16 3 pounds 6 7 7 4kg GN 191 19 8 21 8 pounds 9 0 9 9kg GN 220 19 8 21 8 pounds 9 0 9 8kg INSTALLATION After the valve train components have been properly inspected and serviced install the components as follows 1 Install the intake and exhaust valves through the proper valve guides in the cylinder head a The exhaust valve has the smaller head b The intake valve has the larger head C Valve seat sizes will match their respective valve head sizes d The exhaust valve stem is smaller than the intake valve stem Figure 9 12 Compressing Valve Spring 2 Install the valve spring washers valve springs and valve spring retainers over the valve guides a Hold the valves with your fingers and use your thumbs to compress the spring see Figure 9 12 b When the spring has been compressed sufficiently slide the retainer s small opening over the valve stem and release the spring 3 After both valves have been properly installed position a new head gasket and install the cylinder head NOTE Th
5. Low Oil Switch 9 ft lbs 108 in lbs 9 ft lbs 108 in Ibs 59 9 ft lbs 108 in lbs Printed in U S A Copyright 1999 Power Systems Inc
6. Figure 3 4 Governor Gear Shaft LINKAGE INSTALLATION Differences may exist between governor carburetor linkages depending on the type of equipment on which the engine is used The best method for installation of linkage and springs is to record the attachment points prior to disassembly Rein stall the governor rod link and spring s in the same manner In the typical connection system shown in Figure 3 3 previ ous page the governor rod connects to the governor lever at one end to the carburetor throttle arm at the opposite end In some applications an anti Lash spring also will be con nected at these two points GOVERNOR ADJUSTMENT INITIAL ADJUSTMENT Before starting the engine complete an initial adjustment of the governor as follows 1 Loosen the GOVERNOR LEVER CLAMP BOLT Figure 3 3 2 While holding the GOVERNOR LEVER at its full INC posi tion rotate the GOVERNOR SHAFT clockwise as far as it will go Then tighten the GOVERNOR LEVER CLAMP BOLT TORQUE SPECIFICATION GOVERNOR LEVER CLAMP BOLT 70 inch pounds SECTION 3 MECHANICAL GOVERNOR 3 For adjustable carburetors turn the carburetor IDLE JET in clockwise until it just bottoms DO NOT FORCE Then back the IDLE JET out counterclockwise about 1 1 2 turns see Figure 3 5 4 Turn the MAIN JET Figure 3 5 in clockwise until it just bottoms DO NOT FORCE Then back the MAIN JET out counterclockwise about 1 1 2 turns RUNN
7. 4 Reinstall the GOVERNOR SPRING to the GOVERNOR LEVER and SPEED ADJUST SCREW then tighten the SPEED ADJUST NUT accordingly 5 Reinstall the CAPSCREW into the IDLE CONTROL BRACKET See BLOWER HOUSING SCREW under TORQUE SPECIFI CATIONS page 59 for proper tightness For proper governor adjustment refer to GOVERNOR ADJUSTMENT on this page GOVERNOR GEAR SHAFT REPLACEMENT CAUTION DO NOT TWIST THE GEAR SHAFT WITH A VISE GRIP OR ANY OTHER TOOL THIS COULD RESULT IN ENLARGEMENT OF THE SHAFT BOSS INSPECTION If the governor gear shaft is scored damaged or worn it should be replaced GOVERNOR GEAR SHAFT DIAMETER GN 190 GN 191 GN 220 0 236 0 237 inch 6 004 6 012mm REMOVAL If it becomes necessary to replace the governor gear shaft remove the crankcase cover See Section 11 Use care to avoid damage to the shaft boss area of the crankcase cover Clamp the shaft in a vise then tap the flange with a wooden or plas tic mallet to remove the shaft SECTION 3 MECHANICAL GOVERNOR INSTALLATION Start the new shaft into the shaft boss by tapping lightly with a soft mallet Add red Loctite to the shaft Then use a press or vise to press the shaft into the boss The shaft is properly positioned when its end is just flush with the exter nal boss of the crankcase cover Be sure to wipe away any excess Loctite from the flange CRANKCASE INSTALL SHAFT FLUSH WITH OUTER BOSS
8. DESIGN CLEARANCE 0 0000 0 0010 inch 0 000 0 025mm INNER ROTOR I D DESIGN DIAMETER 0 354 0 355 inch 9 000 9 019mm INNER ROTOR THICKNESS DESIGN THICKNESS 0 312 0 315 inch 7 95 8 00mm 14 OUTER THICKNESS DESIGN THICKNESS 0 314 0 316 inch 8 000 8 025mm OUTER ROTOR DESIGN THICKNESS 1 296 1 297 inch 32 92 32 95mm CRANKSHAFT OIL SEALS An oil seal is provided in the crankcase cover and in the crankcase to prevent oil leakage past the crankshaft jour nals Figure 12 5 A leaking or defective oil seal can be removed and replaced as follows 1 11 the crankshaft has been removed old seals can be removed by tapping out with a screwdriver or by punch ing them out from the inside 2 1 the crankshaft is installed use a commercially available oll seal puller to remove the seals 3 Always use a Seal protector when installing the crankshaft into its bearing bore and when installing the crankcase cover over the crankshaft Figure 12 5 Crankshaft Oil Seals SECTION 12 LUBRICATION PRESSURE RELIEF VALVE DESCRIPTION The ball type pressure relief valve is located in a bore of the crankcase The ball and spring are held in place by a retainer The valve serves to limit oil pressure to a maximum value The ball will remain against its seat as lon
9. SPARK PLUG The spark plug should be cleaned and regapped periodi cally The plug should be replaced every 100 hours of operation or once annually whichever comes first Recommended spark plug is a Champion RC12YC or equiva lent Set soark plug gap to 0 030 inch 0 76mm Figure 8 3 NOTE Always use original GENERAC replacement parts SET PLUG GAP AT 0 030 inch fe ce Q Figure 8 3 Setting Spark Plug Gap FLYWHEEL CHECKING FLYWHEEL MAGNET The flywheel magnet rarely loses its magnetism If you sus pect a magnet might be defective a rough test can be performed as follows 1 Place the flywheel on a wooden surface 2 Hold a screwdriver at the extreme end of its handle and with its point down 3 Move the tip of the screwdriver to about 3 4 inch 19mm trom the magnet The screwdriver blade should be pulled in against the magnet FLYWHEEL KEY In all cases the flywheel s taper is locked on the crankshaft taper by the torque of the flywheel nut A keyway is provided tor alignment only and theoretically carries no load If the flywheel key becomes sheared or even partially sheared ignition timing can change Incorrect timing can result in hard starting or failure to start FLYWHEEL REMOVAL Use a strap wrench to prevent the flywheel from turning Remove the FLYWHEEL NUT Then remove the CONICAL WASHER and the STARTER CUP Use commercially available flywheel puller
10. dure or method We have not undertaken any such wide evaluation Therefore anyone who uses a procedure or method not recom mended by the manufacturer must first satisfy himself that neither his safety nor the product s safety will be endangered by serv ice or operating procedure selected All information illustrations and specifications contained in this manual are based on the latest product information available at the time of publication However GENERAC POWER SYSTEMS INC reserves the right to change alter or otherwise improve the product at any time without prior notice Some components or assemblies of the product described in this manual may not be considered repairable Disassembly repair and reassembly of such components may not be included in this manual The engines described herein may be used to power a wide variety of products Service and repair instructions relating to any such products are not covered in this manual For information pertaining to use of these engines with other products refer to any owner s or service manuals pertaining to said products TABLE OF CONTENTS DIMENSIONS AND FEATURES 3 7 GOVERNOR ADJUSTMENT 19 20 Initial PAG SUC TU KKKTJTTTN T _F 19 20 4 CYCLE ENGINE THEORY 8 20 SECTION 1 GENERAL
11. 8 969 8 987mm SPECIFICATIONS MODEL CRANKSHAFT GN 190 GN 191 CRANKPIN DIAMETER DESIGN DIAMETER 1 180 1 181 Inch 29 99 30 01mm 1 180 1 181 inch 29 99 30 01mm 1 180 1 181 Inch 29 99 30 01mm CRANKSHAFT MAIN BEARING FLYWHEEL END DESIGN DIAMETER 1 102 1 103 Inch 28 000 28 012mm 1 102 1 103 inch 28 000 28 012mm 1 102 1 103 Inch 28 000 28 012mm CRANKSHAFT MAIN BEARING PTO END DESIGN DIAMETER MODEL 1 102 1 103 Inch 28 000 28 012mm 1 102 1 103 inch 28 000 28 012mm CONNECTING ROD ASSEMBLY 1 102 1 103 Inch 28 000 28 012mm LARGE END INSIDE DIAMETER DESIGN DIAMETER 1 183 1 184 Inch 30 06 30 07mm 1 183 1 184 inch 30 06 30 07mm 1 183 1 184 inch 30 06 30 07mm SMALL END INSIDE DIAMETER DESIGN DIAMETER 2 196 2 213 inch 55 8 56 2mm 2 196 2 213 inch 55 8 56 2mm 2 196 2 213 inch 55 8 56 2mm PISTON PIN LENGTH DESIGN DIAMETER 1 102 1 103 Inch 28 000 28 012mm 1 102 1 103 inch 28 000 28 012mm 1 102 1 103 Inch 28 000 28 012mm PISTON PIN OUTSIDE DIAMETER DESIGN DIAMETER MODEL 0 708 0 709 inch 17 989 18 000mm 0 708 0 709 inch 17 989 18 000mm PISTON 0 708 0 709 inch 17 989 18 000mm PISTON MAJOR DIAMETER DESIGN DIAMETER 2 753 2 754 inch 69 939 69 959mm 2 753 2 754 inch 69 939 69 959mm 2 753 2 754 inch 69 939 69 959mm PISTON MI
12. as the ignition and fuel systems Such a check can be per formed quickly and 15 the best method of finding the cause of a failure In addition such a check may provide early detection of future failures CHECK COMPRESSION To check engine compression remove the spark plug Insert an automotive type compression gauge into the spark plug hole Crank the engine until there is no further increase in pressure The highest reading obtained is the engine com pression pressure MINIMUM ALLOWABLE COMPRESSION PRESSURE COLD ENGINE GN 190 GN 191 GN 220 60 psi If compression is poor look for one or more of the follow ing causes Loose cylinder head bolts Failed cylinder head gasket Burned valves or valve seats Insufficient valve clearance Warped cylinder head Warped valve stem Worn or broken piston ring s Worn or damaged cylinder bore Broken connecting rod Worn valve seats or valves Worn valve guides 52 CHECK IGNITION SYSTEM See Testing the Ignition System in Section 8 Page 31 CHECK FUEL SYSTEM Make sure the fuel tank has been properly filled with the correct fuel If the engine is equipped with a fuel shutoff valve make sure the valve is open Make sure fuel is flowing through the fuel line and to the carburetor Adjust the carburetor as needed Make sure the choke closes all the way If engine still will not start remove and inspect the spark plug If the plug is WET look for th
13. cuit board This system is a starter contactor type with the starter contactor energized by circuit board action For instructions and information order DIAGNOSTIC REPAIR MANUAL RECREATIONAL VEHICLE GENERA TORS Generac Part No 94468 STARTER CONTACTOR SYSTEM When the start stop switch is held at START battery current flows through the STARTER CONTACTOR coil and to ground via the switch The starter contactor energizes its contacts close and battery output is delivered to the starter motor The motor energizes and the engine is cranked Figure 6 1 STARTER m a CONTACTOR STARTER MOTOR Figure 6 1 Schematic of Typical Starter Contactor System HEAVY DUTY SWITCH SYSTEM The heavy duty switch contacts are closed manually to deliver battery voltage to the starter motor STARTER MOTOR OPERATING PRINCIPLES Closure of the circuit to the starter motor allows battery cur rent to flow through a commutator to the loops of wire in the armature and back to the battery The interaction of the magnetic fields causes the armature to revolve The armature rotates at a relatively high speed to provide sufficient torque to crank the engine The required engine cranking speed is relatively slow so the starter motor is equipped with a small drive pinion that meshes with the teeth of a flywheel ring gear to crank the engine The large ring gear and the small starter pinion gear results in a gear reduc tion
14. or further repairs may be required 1 Service or replace engine air cleaner as needed 2 Check level and condition of oil Add or change oil as necessary 3 Remove the blower housing Clean dirt from intake screen head and cylinder cooling fins Also remove dirt from car buretor and governor lever s and linkage 4 Clean fuel tank fuel filter s and fuel lines 5 Replace any damaged governor springs 6 If required adjust the carburetor and governor 7 spark plug Use a Champion RC12YC equivalent spark plug a Set spark plug gap to 0 030 inch 0 76mm b Install new plug tighten to 13 ft lbs 156 in Ibs If torque wrench is not available tighten plug with fin gers Then tighten NEW plug 1 2 turn further or USED plug 1 4 turn further Control Rod Assembly Piston Pin Piston Ring Set Gear Cover Assembly M8 x 52mm Head Bolt Piston Pin Retainer Ring Crankshaft Assm Governor R Pin Gov Arm Thrust Washer Crankcase Assembly Crankcase Assembly Governor Arm Oil Seal Governor Gear Assembly Governor Gear C Ring Governor Spool 1 8 NPT Pipe Plug Camshaft Assembly Crankcase Gasket Valve Stem Seal Cylinder Head Gasket Oil Pressure Relief Cover Oil Pressure Spring 11 32 O UJ N TEM
15. see Step 1 under AIR CLEANER BOX INSTALLATION on Page 15 Refer to TORQUE SPECIFICATIONS on Page 59 for proper tightness of carburetor and air box screws NOTE Always use a new gasket when reinstalling the carburetor and or air cleaner box O N A U A 4 DESCRIPTION Carburetor Body Float Float Bowl Bowl Nut Main Jet Fiber Washer Bowl Gasket Float Pin Inlet Valve Fuel Inlet Cap Screw SECTION 2 AIR CLEANERS AND CARBURETION ua veg 7 L 4 P gt 4 b 5 N 7 1 y DESCRIPTION Throttle Shaft Felt Washer Throttle Shaft Spring Screw Throttle Valve Throttle Shaft ldle Jet Spring Idle Speed Screw Primer Bulb Primer Bulb Retainer SECTION 3 MECHANICAL GOVERNOR GOVERNOR OPERATION 1 The governor SPRING tends to pull the LEVER and THROT TLE LINK toward the INC RPM direction 2 As engine speed increases centripetal force acts on the FLY WEIGHT When FLYWEIGHT centripetal force exceeds SPRING force the governor SPOOL is moved axially by FLY WEIGHT force This causes the governor SHAFT to rotate which then moves the LEVER and THROTTLE LINK toward a DEC RPM direction 3 As engine speed decreases a point is reached where gov ernor SPRING force is greater than FLYWEIGHT centripetal SPRING force then moves the LEVER and THROTTLE LINK toward INC RPM 4 Governor action consists of a series of small rom ov
16. 25 35 Hertz C If reading is not within the stated range adjustment of the idle control solenoid is required 8 To adjust the idle control solenoid proceed as follows a Loosen the solenoid JAM NUT then turn the solenoid BOLT clockwise faster or counterclockwise slower b When engine speed is 1500 2100 rpm 25 35 Hertz hold that setting and tighten the solenoid JAM NUT c When JAM NUT is tight check that engine speed is still 1 500 2 100 rpm 25 35 Hertz 23 SECTION 4 OPTIONAL IDLE CONTROL FINAL ADJUSTMENT On the carburetor turn the IDLE STOP SCREW clockwise faster speed until engine speed increases to 2 280 2 400 rpm 38 40 Hertz see Figure 4 4 NOTE Idle speeds less than about 38 Hertz could cause the engine to stall when loads are suddenly applied 0 0 JAM Figure 4 4 Final Adjustment Points SECTION 5 REWIND STARTERS GENERAL The rewind starter used on most GN series engines 15 a manual starter that uses a spring to rewind the starter rope after it has been pulled Pulling the rope winds up a clock type spiral spring In the starter housing When the rope 15 yREMOVE BOLTS released the spring unwinds and causes the rope to wind around the pulley When the rope is pulled outward and away trom the engine spring loaded starter dogs engage the pulley and the engine Is cranked When the rope 15 allowed to return the starter
17. 40 41 SO 40 SECTION 13 TROUBLESHOOTING 52 53 Installation 41 CYEINDER SERVICE 41 SPECIHCATIONS ri 54 59 MP 41 Reboring the Cylinder 41 DIMENSIONS AND FEATURES SMALL FRAME ENGINES ENGINE MODEL DESCRIPTION 60 Hz XL style tapered shaft GN190H Keyed 3 4 unthreaded straight shaft GNI9H 60Hz XE or Xi stylenooilfilter 3 4 straight shaft SAE J609a GeN91H keyed straight shaft GN191RV Vertical tapered shaft Horizontal tapered shaft 3 4 straight shaft 1 straight shaft 3 4 keyed straight shaft GN20H 17 5 8 threaded straight shaft GN220RV No governor parts for use in computer controlled generators If you don t understand any portion of this manual contact In addition to the DANGER WARNING CAUTION and NOTE an authorized Generac service dealer blocks the following blocks indicate specifications or capaci Throughout this publication DANGER WARNING and Cau _ tes as noted TION blocks are used to alert you to special instruction about a particular operation that may be hazardous if performed incor rectly or carelessly Observe them carefully Indicates a fluid capacity These safety warnings cannot eliminate the hazards that 9 they indicate Strict compliance with the special instructions while performi
18. 5 Clean the air cleaner cover Then install the foam pre cleaner into the cover 6 Insert the paper filter into the cover so it holds the pre Cleaner in place 7 Assemble the pre cleaner paper filter and cover to the air Cleaner base AIR CLEANER BOX REMOVAL If the air cleaner box must be removed for further engine disassembly do the following see Figure 2 2 1 Remove the air cleaner cover 2 Remove the foam pre cleaner and paper filter 3 Remove the choke knob units with choke style carburetor 4 Remove the breather hose 5 Remove the cap screw in the upper part of the air cleaner box and the two phillips head screws in the lower part of the air cleaner box CAUTION Removal of the two phillips head screws on a choke style carburetor air cleaner box com bination also will loosen the carburetor from its mount Be careful not to let the carburetor drop as damage to the carburetor and or governor rod and anti lash spring may result BREATHER HOSE L CAP SCREW 2 e Ur AIR CLEANER BOX Y PHILLIPS HEAD SCREWS FOAM PRE CLEANER Figure 2 2 Removal of Air Cleaner Box Primer Style Carburetor HOSE CAP SCREW CHOKE KNOB PRE CLEANER AIR CLEANER BOX PHILLIPS HEAD SCREWS Figure 2 3 Removal of Air Cleaner Box Choke Style Carburetor AIR CLEANER BOX INSTALLATION Install the air cleaner box to the engine and carburetor as follows
19. 7 494 7 520mm 0 295 0 296 Inch 7 494 7 520mm 0 295 0 296 Inch 7 494 7 520mm CRANKSHAFT SLEEVE BEARING DESIGN DIAMETER WHERE APPLICABLE 1 104 1 106 Inch 28 044 28 099mm 1 104 1 106 inch 28 044 28 099mm 1 104 1 106 Inch 28 044 28 099mm GOVERNOR ARM BORE DESIGN DIAMETER 0 239 0 240 Inch 6 07 6 10mm 0 239 0 240 inch 6 07 6 10mm 0 239 0 240 inch 6 07 6 10mm CAMSHAFT BEARING DESIGN DIAMETER 1 024 1 025 inch 26 00 26 03mm 1 024 1 025 inch 26 00 26 03mm 1 024 1 025 inch 26 00 26 03mm GOVERNOR ARM DIAMETER DESIGN DIAMETER Later model small frame GN engines have no crankshaft sleeve bearing MODEL 0 235 0 237 inch 5 97 6 03mm 0 235 0 237 inch 5 97 6 03mm CRANKCASE COVER ASSEMBLY 0 235 0 237 inch 5 97 6 03mm CRANKSHAFT BEARING BORE DESIGN DIAMETER 1 104 1 105 inch 28 040 28 065mm 1 104 1 105 inch 28 040 28 065mm 1 104 1 105 inch 28 040 28 065mm CAMSHAFT BEARING BORE DESIGN DIAMETER 1 299 1 300 inch 33 00 33 03mm 1 299 1 300 inch 33 00 33 03mm 1 299 1 300 inch 33 00 33 03mm GOVERNOR GEAR SHAFT DIAMETER 0 236 0 237 inch 6 004 6 012mm 0 236 0 237 inch 6 004 6 012mm 0 236 0 237 inch 6 004 6 012mm OIL PUMP INNER ROTOR SHAFT DIAMETER DESIGN DIAMETER 0 353 0 354 inch 8 969 8 987mm 0 353 0 354 inch 8 969 8 987mm 0 353 0 354 inch
20. DIAMETER 1 022 1 023 inch 25 96 25 98mm 91 CAMSHAFT DIAMETER PTO END DESIGN DIAMETER 1 022 1 023 inch 25 96 25 98mm SECTION 11 CRANKSHAFT AND CAMSHAFT CRANKSHAFT INSPECTION CRANKSHAFT PROPER Using a commercial solvent clean the crankshaft thor oughly After cleaning inspect the crankshaft as follows 1 Inspect keyways in crankshaft see Figure 11 5 Make sure they are not worn or spread apart Remove burrs from edges of keyways to prevent scratching the bearing 2 Inspect the crankshaft gear for chipping or cracking If timing gear is damaged the crankshaft must be replaced 3 Inspect the crankpin for nicks scratches or other damage Small scratches and nicks can be polished out using fine emery cloth ALL EMERY CLOTH RESIDUE MUST BE COM PLETELY REMOVED USING A SOLVENT SUCH AS KEROSENE 4 Carefully measure the diameters of the crankpin crankshaft journal at flywheel end and the crankshaft journal at PTO end Replace the crankshaft if it is worn beyond the stated repair limits NOTE The crankpin must NOT be ground to any smaller diameter Undersize connecting rods are NOT available CRANKPIN DIAMETER DESIGN DIAMETER 1 180 1 181 inch 29 99 30 01mm CRANKSHAFT MAIN BEARING DIAMETER FLYWHEEL END DESIGN DIAMETER 1 102 1 103 inch 28 000 28 012mm 72 CRANKSHAFT MAIN BEARING DIAMETER END DESIGN DIAMETER 1 1
21. camshaft gears are properly aligned 4 Place the crankcase cover gasket onto the crankcase flange 5 Apply engine oil to the crankshaft and camshaft journals 6 Apply engine oil to the crankshaft and camshaft bores in the crankcase cover 7 Insert tubular end of oil pickup into its crankcase cover bore The pickup screen must face downward and the pickup must be parallel with the cover flange NOTE When the crankcase cover is installed the groove at tip of pickup must mate with a cast protrusion on the crankcase floor The pickup must be properly posi tioned to ensure it will be retained by the cast protrusion after the cover has been installed 8 Make sure the camshaft bore in crankcase cover and the oil pump s inner rotor shaft have been coated with oil 9 Apply a small amount of general purpose grease to the oil pump inner rotor The grease will help prevent that rotor from dropping out when the cover is inverted for installation 10 Install the oil pump inner rotor over the rotor shaft and into the camshaft bore 11 Install the oil pump outer rotor onto the two drive pins at the of the camshaft see Figure 12 10 next page CRANKCASE COVER BOLTS OIL PUMP INNER ROTOR CRANKCASE GASKET OIL PICKUP ASSEMBLY OIL PUMP Pd OUTER ROTOR Figure 12 9 Reassembly of Crankcase Cover and Oil Pump SECTION 12 LUBRICATION CAMSHAFT GEAR DRIVE PINS 4 4 NE Figure 12 10 Loca
22. dogs do not engage the pulley REWIND ASSEMBLY REMOVAL The rewind starter assembly is retained to the engine blower housing by screws and lock washers see Figure 5 1 Remove the screws and lock washers then remove the complete starter rewind assembly 1 Housing Starter Dog 7 Pulley 9 Handle Insert 2 Spring Retainer Pawl 8 Spring and Spring 10 Handle 3 Dog Spring Screw Keeper 11 Rope Figure 5 2 Exploded View of Rewind Starter Old Style 24 DISASSEMBLY OLD STYLE 1 Pry up the HANDLE INSERT to expose knot In ROPE see Figure 5 2 2 Untie knot in ROPE Remove HANDLE INSERT and HANDLE 3 Slowly release spring tension on the PULLEY after the ROPE has been drawn through the HANDLE 4 Remove the SCREW Then remove the RETAINER PAWL STARTER DOGS DOG SPRINGS and SPRING 5 Lift out the PULLEY REASSEMBLY 1 Place SPRING and SPRING KEEPER into position turn to lock into position see Figure 5 2 The spring should be lightly coated with grease 2 Place the PULLEY along with SPRING and SPRING KEEPER into the HOUSING Install SPRING STARTER DOGS and DOG SPRINGS PULLEY AND SPRING zii ASSEMBLY RETAINER RETAINING CLIP HOUSING SECTION 5 REWIND STARTERS 3 Install RETAINER PAWL and SCREW Tighten the SCREW to 65 75 inch pounds 4 Wind the PULLEY counterclockwise until tight Then allow it to unwind until the hole in the PULLEY lines up with the eyelet in the HOUSIN
23. eer wb pee daten ep 19 EE 29 m 19 Installatiofr Ol COVES SHOUTS EK 29 LINKAGE INSTALLATION eem 19 TABLE OF CONTENTS SECTION 8 IGNITION SYSTEM 30 31 SECTION 11 CRANKSHAFT AND CAMSHAFT 42 45 GENERAL 30 CAMSHAFI RENIQNMAL 42 MAJOR COMPONENTS 30 Removal of Crankcase Cover 42 IGNITION COIL ASSEMBLY 30 Camshalt Removal uuruuu u 42 SPARK PLUC 30 CRANKSHAFT REMOVAL LLL 42 EE qammi RUN DAN REDE 30 31 CAMSHAFT INSPECTION 43 CHECKING MAJN E prierai 30 CRANKSHAFT INSPECTION 43 44 PYNE KEY 30 CrankshalE Lu Lu uuu u se ratae 43 Iy 11601 REMOVAL e 30 31 Crankshaft Sleeve 44 Flywheel Installation 31 COMPRESSION RELEASE 44 45 TESTING THE IGNITION SYSTEM 31 CRANKSHAFT INSTALLATION 45 CAMSHAFT INSTALLATION 45 SECTION 9 VALVE TRAIN 32 36 NIAJORCONIPONENIS ae 32 SEMEL 32 33 Cini
24. f g Incorrect spark plug Spark plug is fouled Spark plug porcelain is cracked Incorrect spark plug gap Incorrect valve clearance Weak valve springs Governor not set correctly Incorrect spark plug Incorrect valve clearance Worn piston rings Low oil level Air cleaner is obstructed Valves or valve seats worn or burned Air flow is obstructed Cooling fins are clogged Carbon buildup in combustion chamber Engine is overloaded Lack of lubrication Engine mounting bolts loose Bent crankshaft Problem in equipment connected to engine Fill fuel tank b Replenish oil as necessary c Clean or replace air cleaner element d Clean fuel line or replace e Open cap vent hole f Replace spark plug g Replace with correct spark plug h Check wiring repair or replace Check ignition system replace defective part s 1 Reset valve clearance k Check for worn or scored cylinder a Clean carbon from head and piston b Check flywheel key and keyway replace part s if necessary Tighten flywheel nut c Replace crankcase d Replace connecting rod Check crankpin diameter to see If crankshaft Is bad e Reset to correct clearance Install correct spark plug Clean and regap spark plug Replace spark plug Regap the spark plug Reset valve clearance Replace weak valve spring s Adjust governor Install correct spark
25. load frequency or rpm is correct apply a load to the engine a For AC generator applications connect electrical loads as close as possible to the unit s rated wattages amper age capacity b For nongenerator applications turn on the equipment being powered by the engine 8 With a load applied to the engine adjust the carburetor as follows 20 a CARBURETOR WITH FIXED MAIN JET Slowly adjust the IDLE SPEED SCREW to obtain best operation and high est rpm under load see Figure 3 6 DO NOT EXCEED RPM SPECIFICATION b CARBURETOR WITH ADJUSTABLE MAIN JET Adjust the carburetor as follows 1 Slowly turn the MAIN JET counterclockwise richer until rpm or frequency starts to drop off 2 Turn the MAIN JET clockwise leaner until rpm or fre quency again starts to decrease 3 Turn the MAIN JET counterclockwise richer until the best and most stable frequency or rpm is obtained 9 Turn off all loads and check the no load governor setting Readjust governor no load speed if necessary LOW OIL INDICATOR ENGINE SHUTS OFF AUTOMATIC Figure 3 6 Carburetor Adjustment Typical SN A ON NN V A 2 gt 21 SECTION 4 OPTIONAL IDLE CONTROL GENERAL Some applications such as generators may be equipped with an automatic idle control system This type of system provides greatly improved fuel economy by running the eng
26. not available If the cylinder is worn or damaged the crankcase must be replaced SECTION 10 PISTON RINGS AND ROD ASSEMBLY AND INSTALLATION ASSEMBLY 1 Install the rings Figure 10 4 a Use a ring expander when installing rings into the piston grooves Le N Figure 10 5 Measuring Ring End Gap CONNECTING ROD The connectino rod is manufactured of die cast aluminum Marks on the rod and on the rod cap must be aligned when assembling the to the crankshaft CAUTION DO NOT USE A WASHER WHEN 55 Figure 10 7 Match Marks Facing Up BLING THE ROD CAP b Install the oil ring assembly first c Install the second compression ring with its chamfer NOTE Match marks on the connecting rod and cap facing up must face up in the general direction of the gov ernor shaft when installed see Figure 10 7 Finally install the top compression ring 2 Assemble piston rod and wrist pin a The assembly mark on piston must be toward the engine flywheel side b Coat the wrist pin wrist pin bore in piston and the wrist pin bore in rod with clean engine oil c Install one snap ring into the piston s wrist pin bore NOTE Use new snap rings when reassembling the piston d Assemble the piston to the rod and slide the wrist pin through one piston bore through the rod bore and through the second piston bore until it contacts the snap ring e Finally install the s
27. of the valve spring retainer toward the valve stem b When the larger retainer hole 15 around the valve stem release the valve spring Remove the retainer spring and washer Figure 9 5 Compressing Valve Springs 6 Remove the intake and exhaust valves 7 Clean all parts a Remove carbon from the valve heads and stems b Inspect valves and valve seats c Service parts as outlined under Valve Service VALVE SERVICE VALVE Replace valves if they are damaged distorted or If the the margin is ground to less than 0 039 inch 1mm If valves are in usable con dition grind cut the valve 459V faces 45 angle see Figure 9 6 Figure 9 6 SECTION 9 VALVE TRAIN VALVE SEATS Valve seats are not replace able If they are burned or pitted they can be reground using a grinding stone or Neway Valve Reseater Grind seats at a 46 angle and to a width of 0 039 inch 1 mm see Figure 9 7 SEAT WIDTH 46 Figure 9 7 The recommended procedure for cutting a valve is to use the Neway Valve Cutting System This type of system uses cutters of three different degrees First use the 60 cutter to clean and narrow the seat from the bottom toward the center see Figure 9 8 Second use a 31 cutter to clean and narrow the seat from the top to the center Finally use a 46 cutter to cut in the seat to a width of 0 039 inch 1mm BOTT
28. plug Reset valve clearance Replace piston rings Replenish oil to proper level Clean or replace air cleaner Grind valves and valve seats Remove obstructions Clean cooling fine Remove cylinder head and clean carbon Reduce excessive loading Replenish oil to proper level Tighten mounting bolts b Replace crankshaft c Check equipment driven by engine SPECIFICATIONS MODEL GENERAL SPECIFICATIONS GN 190 GN 191 BORE 2 76 inches 70mm 2 76 inches 70mm 2 95 inches 75mm STROKE 1 93 inches 49mm 1 93 inches 49mm 1 93 inches 49mm DISPLACEMENT 188 6cc 188 6cc 216 5cc OIL CAPACITY W O FILTER CHANGE WITH FILTER CHANGE MODEL 21 ounces 620ml 29 5 ounces 870 ml 21 ounces 620ml 29 5 ounces 870 ml VALVE TRAIN GN 191 21 ounces 620ml 29 5 ounces 870 ml VALVE SEAT WIDTH DESIGN WIDTH 0 034 0 044 inch 0 87 1 13mm VALVE SEAT ANGLE 45 degrees VALVE MARGIN DESIGN MARGIN 0 058 0 060 inch 1 48 1 52mm 0 034 0 044 inch 0 87 1 13mm 0 034 0 044 inch 0 87 1 13mm INTAKE VALVE STEM DIAMETER DESIGN DIAMETER 0 215 0 216 inch 5 465 5 480mm 0 274 0 275 inch 6 965 6 980mm 0 274 0 275 inch 6 965 6 980mm EXHAUST VALVE STEM DIAMETER DESIGN DIAMETER 0 214 0 215 inch 5 445 5 460mm 0 273 0 274 inch 6 965 6 980mm 0 273 0 274 inch 6 965 6 98
29. that can vary in ratio up to 19 to 1 This reduction allows the starter to rotate at high speeds while cranking the engine at low speeds When the engine starts its speed increases quickly For example if the engine reaches 100 rom and the starter pinion remains meshed with the ring gear the starter arma ture would spin at about 1 900 rpm 19 to 1 ratio To prevent damage to the armature a Bendix Drive mechanism is used to disengage the starter pinion from the ring gear when the engine has started THE BENDIX DRIVE When the field coils of the starter drive are energized the armature starts to turn A loose fitting sleeve inside the pinion gear is turned with the armature This sleeve has large spiral threads on its surface that match the pinion gears internal threads The sleeve turns with the armature and the pinion gear rotates on the threads to move outward on the sleeve Outward movement of the pinion gear causes that gear to mesh with the flywheel ring gear The pinion hits a stop on the sleeve and the pinion turns the ring gear and engine On start up the engine turns faster than the armature This causes the pinion to spin back on the spiral threads of the sleeve and out of engagement with the ring gear STARTER MOTOR REPAIRS If the starter motor is defective it should be removed and replaced Disassembly and repair of the motor is not cost effective STARTER MOTOR REMOVAL To remove the starter from the engine loos
30. to remove the flywheel from the engine tapered shaft FLYWHEEL INSTALLATION Align the keyway in the flywheel with the woodruff key on the crankshaft Install the flywheel the conical washer and the starter cup Install the flywheel nut and tighten to the proper torque NOTE The conical washer must be installed in the proper direction see Figure 8 4 with the convex side facing out away from the flywheel TORQUE SPECIFICATION FLYWHEEL NUT 75 foot pounds WOODRUFF js FLYWHEEL Q 4 STARTER CUP CONICAL WASHER FLYWHEEL NUT FLYWHEEL NUT STARTER FLYWHEEL CUP Figure 8 4 Exploded View of Flywheel Assembly TESTING THE IGNITION SYSTEM Use a spark tester to test the ignition system Such spark testers are commercially available Test the system as fol lows 1 Disconnect the high tension lead from the spark plug 2 See Figure 8 5 Attach the spark tester clamp to the engine cylinder head frame ground Attach the spark plug high tension lead to the tester terminal 3 Crank the engine rapidly If soark jumps the gap of the spark tester you may assume the ignition system is operating sat istactorily 31 SECTION 8 IGNITION SYSTEM SPARK TESTER SPARK TESTER CLAMP GROUNDED TO SPARK PLUG BOOT Figure 8 5 Testing Ignition System NOTE If the flywheel key is sheared or partially sheared spark can jum
31. ture The piston should be at top dead center TDC of its compression stroke both valves closed Correct valve clear ance Is given below in INCHES MILLIMETERS ENGINE GN 190 GN 191 GN 220 CLEARANCE 0 001 0 003 0 001 0 0022 0 001 0 0022 INTAKE 0 03 0 07 0 03 0 056 0 03 0 056 CLEARANCE 0 001 0 003 0 0018 0 003 0 0018 0 003 EXHAUST 0 03 0 07 0 046 0 07 0 046 0 07 1 Loosen the rocker arm jam nut Use an allen wrench to turn the pivot ball stud while checking the clearance between the rocker arm and valve stem with a feeler gauge see Figure 9 16 Figure 9 16 Adjusting Valve Clearance 36 2 When clearance is correct hold the pivot ball stud with the allen wrench and tighten the rocker arm jam nut to the specified torque with crow s foot After tightening the jam nut recheck valve clearance to make sure it did not change TORQUE SPECIFICATION ROCKER ARM JAM NUT 72 inch pounds ia Figure 9 17 Tightening the Jam Nut INSTALL ROCKER ARM COVER 1 Use a new rocker arm cover gasket Install the rocker arm cover and retain with four screws 2 Install oil breather tube SN A ON NN V A 2 gt 37 SECTION 10 PISTON RINGS AND ROD GENERAL There no oversize pistons or rings available tor these engines For that reason if the cylinder is damaged or worn excessively the crankc
32. 0 025mm INNER ROTOR BORE DESIGN BORE 0 354 0 355 Inch 9 000 9 019mm 0 354 0 355 inch 9 000 9 019mm 0 354 0 355 Inch 9 000 9 019mm INNER ROTOR THICKNESS DESIGN THICKNESS 0 312 0 315 Inch 7 95 8 00mm 0 312 0 315 inch 7 95 8 00mm 0 312 0 315 Inch 7 95 8 00mm OUTER ROTOR OUTSIDE DIAMETER DESIGN DIAMETER 1 296 1 297 inch 32 92 32 95mm 1 296 1 297 inch 32 92 32 95mm 1 296 1 297 inch 32 92 32 95mm OUTER ROTOR THICKNESS DESIGN THICKNESS 0 314 0 316 Inch 8 000 8 025mm 0 314 0 316 inch 8 000 8 025mm NOTE 2 Measure pump tip clearance on shaft in crankcase cover 58 0 314 0 316 Inch 8 000 8 025mm OIL PUMP CONTINUED SPECIFICATIONS OIL PRESSURE RELIEF VALVE SPRING Force required to compress spring to 1 035 inch 26 3mm MODEL 0 85 0 95 pounds 0 39 0 43kg 0 85 0 95 pounds 0 39 0 43kg COMPRESSION PRESSURE GN 190 GN 191 0 85 0 95 pounds 0 39 0 43kg GN 220 WHILE CRANKING COLD ENGINE MODEL 60 psi min 60 psi min TORQUE SPECIFICATIONS GN 190 GN 191 60 psi min GN 220 Rocker Cover Screws A ft lbs 48 in Ibs 4 ft lbs 48 in lbs 4 ft lbs 48 in Ibs Rocker Arm Jam Nut 14 5 ft lbs 174 in Ibs 14 5 ft lbs 174 in lbs 14 5 ft lbs 174 in Ibs Cylinder Head Bolts 22 ft lbs 264 in Ibs 22 f
33. 02 1 103 inch 28 000 28 012mm 1 Check keyways 2 Crankshaft gear 3 Oil passage 4 Journal flywheel end 5 Journal PTO end 6 Crankpin 7 Threaded ends Figure 11 5 Points to Check on Crankshaft SECTION 11 CRANKSHAFT AND CAMSHAFT CRANKSHAFT SLEEVE BEARING The crankshaft bore in the crankcase 15 a pressure lubricated oil bearing that may or may not include an additional sleeve bearing depending on the vintage of the engine Figure 11 6 The crankshaft bore in the crankcase cover is also pres sure lubricated oil bearing Inspect the bearing and bearing bore as follows 1 Where applicable check the sleeve bearing in the crankcase tor damage a Measure the inside diameter of the sleeve bearing Replace the bearing if it is worn excessively b Press out the old bearing and press a new bearing into place NOTE Alignment of the oil holes in the sleeve bearing and bearing bore in the crankcase is critical CRANKSHAFT SLEEVE BEARING DIAMETER DESIGN DIAMETER 1 104 1 106 inch 28 044 28 099mm 2 Inspect the crankshaft bearing bore in the crankcase cover tor damage and wear Figure 11 7 a Measure the Inside diameter of the bearing bore b If the bore is worn excessively replace the crankcase cover lt gt CRANKCASE BEARING BORE IN CRANKCASE COVER DESIGN DIAMETER 1 1
34. 03 1 105 inch 28 030 28 058mm SLEEVE BEARING OIL SEAL Figure 11 6 Crankshaft Sleeve Bearing CRANKCASE COVER BEARING BORE Figure 11 7 Bearing Bore in Crankcase Cover COMPRESSION RELEASE A mechanical compression release is provided on the camshaft Figure 11 8 A flyweight pivots on a pin mounted in the camshaft gear The pin itself has a cam action When the engine 15 not running the pin holds the tappet up just slightly which in turn holds the exhaust valve slightly open This relieves compression for easier cranking When the camshaft spins the flyweight moves causing the pin to turn The tappet is then free to move normally FLYWEIGHT Figure 11 8 Compression Release Mechanism Measure the amount of compression relief lift at the tappet see Figure 11 9 COMPRESSION RELEASE LIFT GN 190 DESIGN LIFT 0 027 0 055 inch 0 70 1 40mm ES COMPRESSION RELEASE LIFT GN 191 GN 220 DESIGN LIFT 0 020 0 047 inch 0 5 1 2mm TAPPET COMPRESSION RELIEF LIFT CAMSHAFT mA J LOBES Figure 11 9 Compression Relief Lift CRANKSHAFT INSTALLATION Before installing the crankshaft lubricate all bearing sur face
35. 0mm TAPPET DIAMETER INTAKE AND EXHAUST DESIGN DIAMETER 0 294 0 295 inch 7 461 7 475mm 0 293 0 294 inch 7 457 7 475mm 0 293 0 294 inch 7 457 7 475mm VALVE SPRINGS FREE LENGTH FORCE REQUIRED TO COMPRESS SPRING TO 1 39 INCH 35 2mm 1 910 inch 48 48mm 14 8 16 3 pounds 6 7 7 4kg 2 074 inch 52 69mm 19 8 21 8 pounds 9 0 9 9 2 074 inch 52 69mm 19 8 21 8 pounds 9 0 9 9kg VALVE CLEARANCE INTAKE EXHAUST 0 001 0 003 inch 0 03 0 07mm 0 001 0 003 inch 0 03 0 07mm 0 001 0 0022 inch 0 030 056mm 0 0018 0 003 inch 0 07 0 046mm 0 001 0 0022 inch 0 030 056mm 0 0018 0 003 in 0 07 0 046mm VALVE GUIDES DESIGN DIAMETER ALLOWABLE END PLAY 0 216 0 217 inch 5 505 5 520mm 0 237 0 2364 inch 6 02 6 005mm CRANKSHAFT END PLAY 0 006 0 023 inch 0 14 0 60mm 0 006 0 023 inch 0 14 0 60mm 54 0 237 0 2364 inch 6 02 6 005mm 0 006 0 023 inch 0 14 0 60mm ES AN N S Q SOA lt lt As QV XN S il NO 53 d J 7 B CRANKCASE ASSEMBLY GN 190 GN 191 SPECIFICATIONS GN 220 CYLINDER BORE DESIGN DIAMETER 2 756 2 757 inch 70 000 70 025mm 2 756 2 757 inch 70 000 70 025mm 2 953 2 954 inch 75 000 75 025mm VALVE TAPPET BORE DESIGN DIAMETER 0 295 0 296 inch
36. DESCRIPTION 000 DESCRIPTION few 25 1 SECTION 1 GENERAL 8 Check that ignition wires are free of breaks and abrasions and are properly routed 9 Install the blower housing 10 Run engine and adjust engine speeq M5 Form Screw M6 1 0 x 12mm Screw Gov Gear Thrust Washer 8 1 25 x 35mm Screw Spring Washer Valve Spring Retainer Valve Spring Valve Spring Wear Washer Geroter Set O Ring Cylinder Head Assembly Exhaust Valve Intake Valve Push Rod Tappet Oil Pick up Assembly Rocker Cover Gasket Pivot Ball Stud GN 190 220 Rocker Arm Rocker Arm Jam Nut Push Rod Guide Plate 1 4 NPT Pipe Plug Rocker Cover Assembly Plastic Oil Fill Plug SECTION 1 GENERAL OVERSIZE PARTS GENERAL At the time this manual was published oversize pistons rings valves etc were not available Worn or damaged parts must be replaced OVERSIZE PISTONS AND RINGS Oversize pistons and rings are not available at this time The engine cylinder cannot be rebored to an oversize dimension If the cylinder is worn excessively or damaged the crankcase must be replaced A standard size piston and rings can then be used OVERSIZE VALVES Oversize valves are not available at this time Valve guides cannot be rebored to an oversize dimension If valve guides are worn or damaged the cylinder head must be replaced Standard size valves can then be used Valve guides cannot be repla
37. ERTAINING TO THE STORAGE AND HAN DLING OF GASOLINE RECOMMENDED ENGINE OIL Use a clean high quality detergent oil classified For Ser vice SC SD SE SF or SG No special additives should be used with the recommended oil Detergent oils keep the engine cleaner and retard the formation of gum and varnish deposit Synthetic oil can be used in place of petroleum based oils During summer months above 32 F or 0 C use SAE 30 oil SAE 10W 30 oil is an acceptable substitute During winter below 32 or 0 C use SAE 5W 20 or 5W 30 oll e USE SAE 10W 40 OIL CRANKCASE CAPACITY GN190 GN191 GN220 ENGINES WITHOUT OIL FILTER CHANGE 21 ounces 620 ml WITH OIL FILTER CHANGE 29 5 ounces 870 ml CHANGE OIL FILTER Replace oil filter with every oil change Before installing a new oil filter put a light coat of clean oil on rubber o ring on filter base Screw the filter on by hand until o ring touches filter adapter tighten 3 4 turn Check for leaks after starting Check engine oil level each time the equipment is used When checking oil level make sure the equipment is level Change oil after the first eight hours of operation on a new engine Thereafter change oil and filter every 50 hours of oper ation Change oil every 25 hours if operating under extremel dusty or dirty conditions or in very hot weather NOTE Engine may be equipped wit
38. Figure 4 2 Idle Control System Typical AC Generator IDLE CONTROL ADJUSTMENT GENERAL Idle soeed will be correct when a the idle control solenoid is positioned to maintain an idle speed of about 1 500 2 100 rom 25 35 Hertz and b when the carburetor idle speed stop screw 15 adjusted to maintain an idle speed of about 2 280 2 400 rom 38 40 Hertz Once the solenoid has been properly positioned the remain ing fine adjustment of idle speed can be accomplished with the idle speed stop screw on the carburetor INITIAL ADJUSTMENT 1 Set the idle control switch to OFF 2 Unplug all electrical loads from the generator set 3 Connect an AC frequency meter into one of the genera tor s AC power receptacles 4 Crank and start the engine as outlined in the appropriate owner s manual a For units rated 60 Hertz the frequency meter should read about 3 690 3 810 rom high governed speed This is about 61 5 63 5 Hertz b For units rated 50 Hertz the meter should read 3 030 3 090 rpm 50 5 51 5 Hertz 5 Let the engine stabilize and warm up 6 Set the idle control switch to ON The idle control solenoid should energize and engine speed should decelerate to idle speed 7 11 necessary back the carburetor s idle speed stop screw out so that governor lever travel is limited by the solenoid and not by the idle stop screw a Check the frequency meter reading b Meter should indicate about 1 500 2 100 rpm
39. G 5 Pull the ROPE up through the eyelet in the HOUSING then through the HANDLE and HANDLE INSERT Tie a left hand knot in the rope 6 Install the HANDLE INSERT into the HANDLE 7 Test the starter for proper operation TORQUE SPECIFICATION CAP SCREWS ON REWIND TO BLOWER COVER 84 INCH POUNDS DISASSEMBLY NEW STYLE Disassembly of new style rewind starter is not cost effec tive except for ROPE or HANDLE replacement see Figure 5 3 K m m m lt d HANDLE Figure 5 3 Exploded View of Rewind Starter New Style SECTION 6 ELECTRIC STARTERS AND BATTERIES INTRODUCTION Some GN series engine applications may be equipped with 12 volt DC electric cranking system Such a system converts electrical energy trom a battery into mechanical energy at the starter motor for the purpose of turning the engine over for starting Generally two types of cranking systems are used in GN series engine applications These are a the starter contac tor system and b the heavy duty cranking switch system NOTE Cranking systems discussed in this manual are typical systems The actual cranking system used in specific applications may differ Refer to the wiring diagram and or electrical schematic in the Owner s Manual for specific applications NOTE Vertical crankshaft engines used in recreational vehicle applications are equipped with a cranking and starting system that is controlled by a solid state cir
40. HEORY If the engine is to run properly four 4 events must occur in the proper sequence and at the correct time These events are a intake b compression c ignition and power and d exhaust A INTAKE The piston is travelling from top dead center TDC to bottom dead center BDC The cam has opened the intake valve The piston s downward movement in the cylinder creates a partial vacuum in the cylinder Air at atmos pheric pressure is drawn into the cylinder through the carburetor and is mixed with fuel in the carburetor The fuel air mixture flows through the open intake valve into the cylinder When the piston reaches BDC the intake stroke is over AISAT 7 7 B COMPRESSION As the piston reaches bottom dead center BDC both the intake and exhaust valves are closed The piston moves upward toward TDC and the fuel air mixture is com pressed Just before the piston reaches TDC ignition occurs C IGNITION AND POWER By the time the piston reaches TDC combustion is already in progress The intake and exhaust valves remain closed as the expanding gases of combustion force the piston downward D EXHAUST The exhaust stroke begins when the piston has reacheq BDC and has started its upward movement The intake valve is closed The exhaust valve is open to let gases escape Purpose and Scope of Manual This manual contains all information normally required to service
41. I q 20 0 79 22 0 87 159 6 26 206 5 8 13 lt 29 2 2 gt 2 UJ uJ DIMENSIONS AND FEATURES STARTER SIDE VIEW AM O 2 CLEANER PTO CRANKSHAFT OPTIONS VIEW UNIVERSAL TAPER HORIZONTAL STRAIGHT 219 90 748 P N 21859 5 25 12 TAPER P N 21861 ANGLE WITH CENTER LINE 5 217 214 5 35583 27 3 1 1 94 050 0 159 5 16 24 UNF 2B 94 000 0 157 24mm THREAD DEPTH M16 X1 5 15 5mm LONG ZAA 15 5 0 610 228 000 1 102 928 012 1 103 925 0 98 928 012 1 103 GUAGE DIA 4 775 0 188 4 725 0 186 61 6 2 4 50 37 1 98 EM U 1 102 ENGINE 1 22 946 0 903 6 0 236 1 914 400 0 567 216 56 0 664 013 600 0 535 68 2 68 916 25 0 639 19 05 0 75 90 3 543 gt 219 02 0 74 lt amp REFERENCE SAE J609A GAUGE LINE
42. ING WIDTH DESIGN WIDTH 0 111 0 118 inch 2 825 3 003mm 0 111 0 118 inch 2 825 3 003mm 0 111 0 118 inch 2 825 3 003mm OIL CONTROL RING END GAP DESIGN END GAP 0 015 0 055 Inch 0 38 1 40mm 0 015 0 055 Inch 0 38 1 40mm 0 015 0 055 Inch 0 38 1 40mm NOTE 1 Measure end with ring pushed down in cylinder to depth of 2 75 inches S4 SPECIFICATIONS MODEL CAMSHAFT ASSEMBLY MAIN CAMSHAFT BEARING DIAMETER FLYWHEEL END DESIGN DIAMETER 1 022 1 023 inch 25 96 25 98mm 1 022 1 023 inch 25 96 25 98mm 1 022 1 023 inch 25 96 25 98mm MAIN CAMSHAFT BEARING DIAMETER PTO END DESIGN DIAMETER 1 022 1 023 inch 25 96 25 98mm 1 297 1 298 inch 32 96 32 98mm 1 297 1 298 inch 32 96 32 98mm CAM LIFT DESIGN LIFT 0 210 0 212 inch 5 34 5 38mm 0 210 0 212 inch 5 34 5 38mm 0 210 0 212 inch 5 34 5 38mm BASE CIRCLE DIAMETER OF CAM DESIGN DIAMETER 0 978 0 990 inch 24 85 25 15mm 0 978 0 990 inch 24 85 25 15mm 0 978 0 990 inch 24 85 25 15mm COMPRESSION RELEASE LIFT MEASURED AT TAPPET DESIGN LIFT MODEL 0 027 0 055 Inch 0 70 1 40mm GN 190 0 027 0 055 Inch 0 70 1 40mm PUMP GN 191 0 027 0 055 Inch 0 70 1 40mm GN 220 PUMP TIP CLEARANCE DESIGN CLEARANCE 0 0000 0 0010 inch 0 000 0 025mm 0 0000 0 0010 inch 0 000 0 025mm 0 0000 0 0010 Inch 0 000
43. ING ADJUSTMENT After completing the INITIAL ADJUSTMENT final adjustment can be accomplished with the engine running Proceed as follows NOTE For AC generator applications disconnect or turn OFF all electrical loads For nongenerator applica tions turn OFF the equipment being powered Initial checks and adjustments will be accomplished with engine at no load 1 If so equipped set the idle control switch to OFF 2 Start the engine let it warm up and stabilize at no load 3 For AC generator applications connect an AC frequency meter to one of the generator s AC output receptacles a If the generator is rated 60 Hertz the no load AC fre quency reading should be 61 5 63 5 Hertz b If the generator is rated 50 Hertz the no load AC fre quency should be 50 5 51 5 Hertz 4 For non generator applications pumps pressure washers etc refer to the product DATA PLATE for rated engine speed Use a tachometer to read engine speed NOTE Several types of inexpensive tachometers are commercially available 5 lf the frequency or rpm reading is incorrect turn the SPEED ADJUST NUT Figure 3 3 on the governor until fre quency or rpm is within limits 6 frequency or rpm is unstable turn the IDLE SPEED SCREW on carburetor until engine stabilizes DO NOT TURN THE IDLE SPEED SCREW IN FURTHER THAN NECESSARY Fine tune this adjustment after the engine has warmed up and stabilized Adjust it 1 8 turn at a time 7 When the no
44. ING WASHER TAPPETS Figure 11 2 Camshaft Removal CRANKSHAFT REMOVAL 1 The engine flywheel must be removed before attempting to remove the crankshaft See Section 8 2 The piston and connecting rod must be removed Refer to Section 10 3 Remove the crankshaft Figure 11 3 Figure 11 3 Crankshaft Removal CAMSHAFT INSPECTION Carefully inspect the entire camshaft for wear nicks other damage All areas indicated in figure 11 4 should be inspected 1 Check spring pins 2 Camshaft gear 3 Compression release parts 4 Main bearing flywheel end 5 Main bearing PTO end 6 Cam lobes S 1 ZZ L 5 Figure 11 4 Points to Check on Camshaft Carefully measure the following to check them for wear If wear limits are exceeded replace the defective part E CRANKSHAFT BEARING BORE IN CRANKSHAFT COVER DESIGN DIAMETER 1 299 1 300 inch 33 00 33 03mm CRANKSHAFT BEARING BORE IN CRANKCASE DESIGN DIAMETER 1 024 1 025 inch 26 00 26 03mm CRANKCASE SLEEVE BEARING IN CRANKCASE DESIGN DIAMETER 1 104 1 106 inch 28 044 28 099mm CRANKCASE BEARING BORE IN CRANKCASE COVER DESIGN DIAMETER 1 103 1 105 inch 28 030 28 058mm CAM LIFT AT BOTH CAM LOBES DESIGN LIFT 0 210 0 212 inch 5 34 5 38mm CAMSHAFT DIAMETER FLYWHEEL END DESIGN
45. NOR DIAMETER DESIGN DIAMETER 2 747 2 748 inch 69 789 69 809mm 2 747 2 748 inch 69 789 69 809mm 56 2 747 2 748 inch 69 789 69 809mm SPECIFICATIONS PISTON CONTINUED MODEL GN 190 GN 191 GN 220 WRIST PIN BORE DIAMETER DESIGN DIAMETER 0 708 0 709 Inch 18 000 18 01 1mm 0 708 0 709 inch 18 000 18 01 1mm 0 708 0 709 inch 18 000 18 01 1mm TOP RING GROOVE WIDTH DESIGN WIDTH 0 059 0 061 inch 0 059 0 061 inch 0 059 0 061 inch 1 52 1 54mm 1 52 1 54mm 1 52 1 54mm SECOND RING GROOVE WIDTH DESIGN WIDTH 0 059 0 061 inch 0 059 0 061 inch 0 059 0 061 inch 1 52 1 54mm 1 52 1 54mm 1 52 1 54mm OIL CONTROL RING GROOVE WIDTH DESIGN WIDTH 0 118 0 119 inch 3 01 3 03mm 0 118 0 119 inch 3 01 3 03mm 0 118 0 119 inch 3 01 3 03mm TOP RING WIDTH DESIGN WIDTH 0 057 0 059 Inch 1 47 1 49mm 0 057 0 059 Inch 1 47 1 49mm 0 057 0 059 Inch 1 47 1 49mm TOP RING END GAP DESIGN END GAP 0 005 0 016 Inch 0 15 0 40mm 0 005 0 016 Inch 0 15 0 40mm 0 005 0 016 inch 0 15 0 40mm SECOND RING WIDTH DESIGN WIDTH 0 057 0 059 Inch 1 465 1 490mm 0 057 0 059 Inch 1 465 1 490mm 0 057 0 059 Inch 1 465 1 490mm SECOND RING END GAP DESIGN END GAP 0 006 0 016 inch 0 15 0 40mm 0 006 0 016 inch 0 15 0 40mm 0 006 0 016 inch 0 15 0 40mm OIL CONTROL R
46. OLTS DC MINIMUM MOTOR RPM 800 MAXIMUM AMPS 9 If the starter does not perform satisfactorily it should be replaced BATTERY MAINTENANCE GENERAL Many of the batteries in use today are maintenance free and require little or no maintenance In most cases battery failure requires replacement of the battery The lead acid cells found in many products however still require mainte nance Maintenance of lead acid batteries falls into three categories e nspecting the battery e Maintaining proper electrolyte levels e Charging the battery properly INSPECTING THE BATTERY Inspect the battery case for cracks or signs of damage Inspect battery terminals periodically and keep them clean NOTE Always make sure that the battery is fully charged ELECTROLYTE LEVEL Check the battery electrolyte level regularly When level is low add distilled water to the correct level NOTE After adding distilled water do not check elec trolyte specific gravity until after the battery has been recharged Adding of sulfuric acid is NOT recommended If the battery has been recharged and specific gravity is not correct replace the battery TESTING A BATTERY 1 Visually inspect the battery case for cracks and other defects If damaged replace the battery 2 Check the electrolyte level in all battery cells a If distilled water is added recharge the battery before taking a specific gravity reading b Charge the battery unt
47. OM NARROWING CUTTER BOTTOM NARROWING TOP NARROWING CUTTER TOP NARROWING lt TOP S B BOTTOM 5 NARROW Figure 9 8 Cutting Valve Seat SECTION 9 VALVE TRAIN VALVE SERVICE CONTINUED VALVE GUIDES Valve guides are permanently installed in the cylinder head and cannot be replaced see Figure 9 9 At the time of this writing oversize valves were NOT avail able Thus if valve guides are worn or damaged the guides cannot be reamed to accommodate an oversize valve stem DESIGN DIAMETER OF VALVE GUIDES GN 190 0 218 0 217 inch 5 445 5 460mm GN 191 0 273 0 274 inch 6 965 6 980mm GN 220 0 273 0 274 inch 6 965 6 980mm INTAKE VALVE STEM DIAMETER GN 190 0 215 0 216 inch 5 465 5 480mm GN 191 0 274 0 275 inch 6 965 6 980mm GN 220 0 274 0 275 inch 6 965 6 980mm EXHAUST VALVE STEM DIAMETER GN 190 0 214 0 215 inch 5 445 5 460mm GN 191 0 273 0 274 inch 6 965 6 980mm GN 220 0 273 0 274 inch 6 965 6 980mm N N N N N N N N N N N VALVE GUIDES Figure 9 9 Valve Guides in Cylinder Head VALVE TAPPETS The valve tappets Figure 9 10 will be removed when the camshaft is removed Intake and exhaust valve tappets are iden tical However once a wear pattern has been established the two parts should not be interchanged Figure 9 10 Tappet 34
48. Service and Repair for Small Frame P N C1103 E ERIS E Ao ss aE includes 320 360 41 P L 4 Map LA BI ed r ee tlm al gi PP x EZ A FOREWORD This manual has been written and published by POWER SYSTEMS INC to aid our dealers mechanics company serv ice personnel and general consumers when servicing the products described herein It is assumed that these personnel are familiar with the servicing procedures for these products or like or similar products manufac tured and marketed by GENERAC POWER SYSTEMS INC It is also assumed that they have been trained in the recommended servicing procedures for these products which includes the use of mechanics hand tools and any special tools that might be required Proper service and repair is important to the safe economical and reliable operation of the products described herein The trou bleshooting testing service and repair procedures recommended by GENERAC POWER SYSTEMS INC and described in this manual are effective methods of performing such operations Some of these operations or procedures may require the use of specialized equip ment Such equipment should be used when and as recommended We could not possibly know of and advise the service trade of all conceivable procedures or methods by which a service might be per formed nor of any possible hazards and or results of each proce
49. WER SHROUD LOWER SHROUD CAP SCREW TORQUE TO 48 INCH POUNDS Figure 7 1 Exploded View of Engine Covers and Shrouds SECTION 8 IGNITION SYSTEM GENERAL The ignition system typically used on GN 190 GN 191 and GN 220 engines is a solid state breakerless type The system utilizes a magnet on the engine flywheel to induce a relatively low voltage into an ignition coil assembly Ignition coil inter nal components Increase the voltage and deliver the resulting high voltage across the spark plug gap The ignition coil houses a solid state circuit board that con trols ignition timing Timing is fixed nonadjustable and spark advance is automatic MAJOR COMPONENTS Major components of the ignition system include a the ignition coil assembly b the spark plug c the engine run switch and d the engine flywheel see Figures 8 1 and 8 4 ENGINE RUN SWITCH ASSEMBLY Figure 8 1 Ignition System Components IGNITION COIL ASSEMBLY Solid state components encapsulated in the ignition coil are not accessible and cannot be serviced If the coil is defective the entire assembly must be replaced The air gap between the coil and the flywheel magnet is fixed and nonadjustable The ignition coil assembly Figure 8 2 consists of a igni tion coil b spark plug high tension lead and c spark plug boot SPARK PLUG HIGH TENSION LEAD 00 IGNITION COIL Figure 8 2 Ignition Coil Assembly
50. amage 3 Check all bearing surfaces for wear scoring or other damage REBORING THE CYLINDER At the time this Manual was published oversize pistons and rings were not available and reboring of the cylinder to an oversize cannot be done CAUTION DO NOT ATTEMPT TO REBORE THE CYLINDER OVERSIZE PARTS ARE NOT AVAILABLE SECTION 11 CRANKSHAFT AND CAMSHAFT CAMSHAFT REMOVAL REMOVAL OF CRANKCASE COVER Before attempting to remove the crankcase cover remove rust burrs and paint from the power take off PTO end of the crankshaft This will reduce the possibility of damaging the oil seal in the crankcase cover during cover removal 1 Drain oil from crankcase 2 Remove engine cylinder head push rods and push rod guide plate See Section 9 3 Remove all bolts that retain the crankcase cover 4 Remove the crankcase cover Figure 11 1 If necessary tap lightly with a soft hammer on alternate sides of cover Be aware that the oil pump rotors may drop out as the crankcase cover 15 removed Figure 11 1 Crankcase Cover Removal CAMSHAFT REMOVAL See Figure 11 2 1 Tip the engine over onto the flywheel end of the crank shaft 2 Reach in with two fingers and hold the tappets up and clear of the camshaft lobes Then remove the camshaft 3 Remove the two tappets 4 Remove the outer and inner oil pump rotors 5 Remove the camshaft and spring washer 42 OIL PUMP ROTORS CAMSHAFT LOBES SPR
51. ase must be replaced CONNECTING CONNECTING ROD CAP CONNECTING ROD CAP Figure 10 1 Pistons Rings and Connecting Rod REMOVAL Before attempting to remove the piston and connecting rod clean all carbon from the cylinder bore to prevent ring break age Then remove the piston and rod as follows 1 Remove the cylinder head see Section 9 2 Remove the crankcase cover see Section 11 2 Remove the connecting rod cap bolts and the connecting rod cap 3 Push the piston and rod out through top of cylinder PISTON be NEO r ae Figure 10 2 Piston Wrist Pin and Snap Ring REMOVAL FROM CONNECTING ROD An oil hole in the wrist pin area of the piston helps distribute oil to aid in cooling This oil hole also provides an assist in removing the wrist pin snap ring To remove the piston trom the rod proceed as follows 1 Move the snap ring around until its protruding wire is aligned with the notched out oil hole Use needle nose pliers to turn the snap ring and pull it toward you 2 With one snap ring removed slide the wrist pin out of its piston boss Completely remove the wrist pin and separate the piston from the connecting rod CHECK PISTON FOR WEAR The piston 15 slightly elliptical Its larger diameter 15 90 from the wrist pin boss its smaller diameter is in line with the wrist pin boss see Figure 10 3 NOTE An assembly mark is provided on the
52. assages as well as Its seating surface for damage Replace if worn dam aged or defective 4 f so equipped inspect the MAIN JET ADJUSTMENT Replace if necessary NOTE Later production carburetor may not be equipped with a MAIN JET ADJUSTMENT 5 The FLOAT BOWL Item 3 must be free of dirt and corro sion Use a new gasket when assembling the FLOAT BOWL NOTE The float setting is FIXED and NONADJUSTABLE 6 Replace the FLOAT Item 3 if necessary 7 After cleaning metal parts in cleaner blow out all carbu retor passages with compressed air DO NOT ALLOW CARBURETOR METAL PARTS TO SOAK A FOR LONGER THAN 10 MINUTES OR THEY MAY BE DAMAGED NEW STYLE NONADJUSTABLE TYPE EMISSION CARBURETOR Generac recognizes that there are spray type car buretor cleaners on the market however Generac does not authorize the use of carburetor cleaners Also Generac does not recommend soaking a car buretor in any cleaners since the carburetor might be damaged NOTE A MAIN JET TUBE 15 pressed into the carburetor body to a measured depth Do NOT attempt to remove this tube Tube movement will adversely affect carbu retor metering characteristics CARBURETOR INSTALLATION To reinstall a primer style carburetor line up the mounting holes on the carburetor with the holes on the intake mani told and install the two screws Then install the lock nuts and washers onto the screws see Figure 2 6 To reinstall a choke type carburetor
53. case breather on vertical shaft GN series engines is mounted on the crankcase assembly and is configured differently See SERVICE MANUAL COM PUTER CONTROLLED VARIABLE SPEED RV GENERATORS Manual Part No 94468 A BREATHER TUBE ROCKER ARM COVER Figure 12 7 Breather INSPECTION 1 Remove the breather tube Check tube for cracks hard ening or other damage Replace if necessary 2 Clean the rocker arm cover in commercial solvent 3 Make sure the two small drain holes are open If neces sary use a length of wire to open the holes 4 Check the rivets that retain the check valve make sure they are tight 5 The breather plate is retained in the rocker arm cover with a continuous bead of Type 103 black RTV sealant This sealant must not leak Test the sealant for leakage as follows a Seal all holes on the breather plate b Apply air pressure of 5 psi 0 352 kg cm through the breather hose hole No leakage must be observed c If necessary reseal the plate with Type 103 black RTV sealant CRANKCASE COVER DESCRIPTION The die cast aluminum crankcase cover is retained to the crankcase with six flanged head bolts Install a new gasket between the cover and crankcase each time the cover is removed Bores are provided in the cover for a oil pump rotors and camshaft b crankshaft gov ernor gear asse
54. ced NOTE Always use original GENERAC replacement parts NOTES 13 SECTION 2 AIR CLEANERS AND CARBURETION AIR CLEANER SERVICING The engine will not run properly and may be damaged if it Is run with a dirty air cleaner Clean or replace the paper filter every 25 hours of opera tion or once annually whichever occurs first Clean or replace the paper filter more often if operating in extremely dusty or dirty conditions Clean or replace the foam pre cleaner every 25 hours of operation more frequently under dirty or dusty conditions FOAM PRE CLEANER To clean or replace the foam pre cleaner 1 Remove the air cleaner cover then remove the foam pre Cleaner 2 Wash the foam pre cleaner in soapy water 3 Squeeze the pre cleaner dry with a clean cloth DO NOT TWIST NOTE If the pre cleaner is still dirty after washing and drying it replace it with a new filter 4 Apply enough clean engine oil to saturate the pre cleaner 5 Wrap the pre cleaner in a clean dry cloth and squeeze out excess oil DO NOT TWIST Set the pre cleaner aside AIR CLEANER BASE FOAM PRE CLEANER PAPER FILTER AIR CLEANER COVER Figure 2 1 Typical Air Cleaner PAPER FILTER 1 Remove the air cleaner cover 2 Remove the foam pre cleaner and service it if necessary 3 Remove the paper filter 4 Clean the paper filter by tapping gently on a flat surface If it is very dirty replace it
55. e and repairs the engine shrouds and covers may need to be removed The following section briefly describes the order in which these items should be removed 1 Remove air cleaner assembly and carburetor as described in Section 2 AIR CLEANERS AND CARBURETION 2 Remove the nine capscrews from the BLOWER HOUSING Carefully remove the blower cover making sure not to stretch the wires from the RUN STOP switch and low oil indi cator LOS When the cover is far enough away from the engine these wires may be unplugged 3 Remove the capscrew from the LOWER SHROUD see Figure 7 1 4 Remove the remaining capscrew from the UPPER SHROUD see Figure 7 1 UPPER SHROUD BLOWER HOUSING CAPSCREW TORQUE TO 84 INCH POUNDS Y D lt 7 Z lt Yee SS 0 BLOWER HOUSING ASSEMBLY SECTION 7 COVERS AND SHROUDS NOTE The blower cover is notched at the point where the governor rod and anti lash spring pass through it This allows the cover to be removed without discon necting the governor rod from the governor arm NOTE It will be helpful to make note of the locations of the screws that hold the covers in place INSTALLATION OF COVERS AND SHROUDS To reinstall the covers and shrouds reverse the previous steps Make sure that the wires for the RUN STOP switch and low oil indicator LOS are not in the way of the covers during reassembly UPPER SHROUD 2 CAPSCREW TORQUE TO 48 INCH POUNDS LO
56. e following 1 Overchoking 2 Dirty air cleaner 3 Excessively rich fuel air mixture 4 Water in the fuel 5 Fuel leaking past the carburetor float needle If the plug is DRY look for the following 1 Carburetor mounting gasket leaks 2 Dirt or gum in carburetor or fuel line 3 Carburetor float needle stuck closed 4 Inoperative fuel pump if so equipped 5 Clogged fuel filter if so equipped One way to determine if fuel is reaching the engine com bustion chamber is to remove the spark plug and pour a small amount of gasoline into the spark plug hole Reinstall the spark plug and crank the engine If engine fires a few times then quits check for the same conditions as a dry plug SECTION 13 TROUBLESHOOTING PROBLEM POSSIBLE CAUSES Fuel tank is empty Low oil level Dirty air cleaner 1 Engine will not start or starts with difficulty 2 Engine knocks 3 Engine misses under load 4 Engine lacks power 5 Engine overheats 6 Engine vibrates excessively Obstructed Line Fuel tank cap vent hole is obstructed Spark plug is fouled Incorrect spark plug Loose or defective ignition wiring No ignition spark Incorrect valve clearance Poor compression Carbon in combustion chamber Loose flywheel Worn cylinder Loose or worn connecting rod Incorrect valve clearance a b amp d l b d
57. e generator current will flow through the primary windings of a sensing transformer A proportional voltage and current will then be induced into the transformer s secondary windings c Current from the transformer secondary windings is delivered to the circuit board Circuit board action then opens the circuit to an idle control solenoid d The idle control solenoid de energizes and engine speed 5 established by the engine governor e When electrical loads are disconnected or turned off cur rent flow through the transformer primary windings will terminate Voltage and current cannot be induced into the transformer secondary windings f Zero current flow of the transformer secondary wind ings is sensed by the circuit board The circuit board then closes the circuit to the idle control solenoid The sole noid energizes g The energized solenoid pulls the carburetor throttle arm against its idle speed stop screw The engine decelerates to idle speed about 2 280 2 400 rpm 38 40 Hertz 2 ldle control switch set to OFF a AC power is not available to the circuit board The idle control solenoid will then remain de energized at all times b The engine will run at high governed speed Py CH N TRANSFORMER 11X44 CIRCUIT BOARD SWITCH B Pictorial
58. e head gasket is coated with a special sub stance for better sealing It must be free of nicks scratches and other defects or leakage will result 4 Install the cylinder head bolts and tighten them in the sequence shown in Figure 9 13 and to the first torque spec ification listed below Then tighten in the same sequence again to the second torque specification TORQUE SPECIFICATION CYLINDER HEAD BOLTS First Sequence TORQUE 15 foot pounds 180 inch pounds CYLINDER HEAD BOLTS Second Sequence TORQUE 22 foot pounds or 264 inch pounds Figure 9 13 Head Bolt Tightening Sequence 5 Position the push rod guide plate on the head Install the rocker arm and pivot ball stud Install the jam nut far enough to hold the guide plate in position Valve clearance will be adjusted later 35 SECTION 9 VALVE TRAIN 6 Install the push rod with either end resting on the tappet Figure 9 15 a Place the push between the guide plate tabs then place the rocker arm onto the end of the push rod b Push rod alignment is correct when the push rod ball rests in the rocker arm socket Installation of valve train parts is now complete Valve clearance must be adjusted before the rocker arm cover 15 installed ROCKER PUSH ROD GUIDE PLATE X ROD Figure 9 15 Installing the Push Rods SECTION 9 VALVE TRAIN ADJUSTING VALVE CLEARANCE Adjust valve clearance with the engine at room tempera
59. econd snap ring to retain the wrist pin Figure 10 6 Match Marks on Rod and Cap in the piston and rod bores 40 INSTALLATION 1 Coat the cylinder walls with clean engine oil 2 Coat crankshaft crankpin connecting rod bearing and connecting rod cap bearing with engine oil 3 Reinstall the crankshaft 4 Use a ring compressor to compress the piston rings back into their grooves in the piston Rings must be fully com pressed 5 Guide the connecting rod into the cylinder carefully The assembly mark on the piston must be toward the flywheel side of engine 3 o clock position 6 When the ring compressor contacts top of cylinder use a wood hammer handle to gently tap the piston down into the cylinder 7 Check that the connecting rod large diameter bearing is coated with clean engine oil as well as the crankpin and connecting rod cap 8 Guide the connecting rod large diameter bearing over the crankshafts crankpin rod journal 9 Install the connecting rod cap with its match mark aligned with identical mark on rod 10 Install the connecting rod cap bolts and tighten to the proper torque 41 SECTION 10 PISTON RINGS AND ROD TORQUE SPECIFICATION CONNECTING ROD CAP BOLTS GN 190 GN 191 GN 220 120 inch pounds or 10 foot pounds CYLINDER SERVICE INSPECTION 1 Inspect cylinder for dirty broken or cracked cooling fins 2 Check cylinder wall for wear scoring or other d
60. en and dis connect the starter wire then remove the two hex head screws that hold the starter in place STARTER MOTOR INSTALLATION To install the starter motor reverse the previous steps TORQUE SPECIFICATION HEX HEAD SCREWS ON STARTER MOTOR 216 INCH POUNDS TORQUE SPECIFICATION STARTER MOTOR WIRE NUT 84 INCH POUNDS TESTING THE STARTER MOTOR CHECKING THE PINION When the starter motor is activated the pinion gear should rise and engage the ring gear If the pinion does not rise nor mally inspect the large spiral threads of the sleeve and pinion for binding or sticking TOOLS FOR STARTER PERFORMANCE TEST The following equipment may be used to complete a per formance test of the starter motor e A digital multimeter VOM e A tachometer capable of reading up to 1 500 rom e A fully charged 12 volt battery STARTER PERFORMANCE TEST 1 Set the meter to read DC amps 2 Connect the STARTER MOTOR BATTERY and VOM as shown in Figure 6 2 RED Jat LEAD 5 AS qa 3 r7 00 N IN A di STARTER MOTOR BLACK WIRE RED WIRE gt Td Figure 6 2 Starter Performance Test 3 Insert the tachometer at end of the pinion gear and acti vate the starter motor A starter motor in good condition will be within the following specifications 2 SECTION 6 ELECTRIC STARTERS AND BATTERIES STARTER MOTOR PERFORMANCE SPECIFICATIONS AT 12 V
61. ershoots and undershoots as SPRING force increases rom and FLY WEIGHT centripetal decreases rom 5 The point at which SPRING tension and FLYWEIGHT force are equal is the governed speed of the engine SPEED ADJUST SPRING SHAFT GOVERNOR GEAR CENTRIPETAL FORCE TO THROTTLE LINK DEC RPM INC RPM FLYWEIGHT SS y REI N 4 po CRANKSHAFT GEAR CRANKSHAFT PTO END Figure 3 1 Governor Operating Diagram GOVERNOR INTERNAL PARTS See Figure 3 2 A governor gear shaft is pressed into a bore in the engine crankcase cover Internal governor components include a a THRUST WASHER b GOVERNOR GEAR ASSEM BLY SNAP RING d GOVERNOR SPOOL and e GOVERNOR SHAFT A lockpin and washer retain the governor shaft in the crankcase cover The governor gear assembly houses the governor flyweights Flyweight movement causes the spool to move axially In turn axial movement of the spool results in rotation of the governor shaft GOVERNOR GEAR ASSEMBLY GOVERNOR SPOOL THRUST amp _ LOCK PIN d RING aw SHAFT Figure 3 2 Internal Governor Parts GOVERNOR EXTERNAL PARTS Typical external governor parts are shown in Figure 3 3 A GOVERNOR LEVER is clamped to the govern
62. g as oil pressure 15 below about 30 psi 29 kg cm Should oil pressure increase above that value the ball will be forced off 15 seat to relieve excess pressure into the crankcase see Figure 12 6 1 SCREW 2 RETAINER 3 SPRING 4 BALL Figure 12 6 Oil Pressure Relief Valve INSPECTION Remove the SCREW that retains the RETAINER to the crankcase Remove the RETAINER SPRING and BALL Figure 12 6 Clean all parts in solvent Inspect the BALL and RETAINER for damage wear Replace any damaged or worn part Inspect the SPRING replace if damaged or worn Apply a known test load to the spring sufficient to com press the spring to a length of 1 03 inch 26 3mm The amount of test load at the stated spring length should be within the following limits 3 0 85 0 95 pounds 0 43 0 39kg Replace the spring if the test load at the stated length is not within limits BREATHER ASSEMBLY DESCRIPTION A crankcase breather is located in the rocker arm cover of horizontal crankshaft engines Figure 12 7 The breather serves to maintain a reduced pressure in the engine crankcase to prevent oil from being forced past the oil seals gaskets or piston rings The CHECK VALVE allows excess pressure to be vented out of the crankcase and to atmosphere through the BREATHER TUBE Two small DRAIN HOLES allow condensed oil vapors to return to the crankcase NOTE The crank
63. h automatic low oil shutdown capability If so equipped it will not start when oil level is low See Section 12 Lubrication STORAGE INSTRUCTIONS The engine should be started at least once every seven days and allowed to run for at least 30 minutes If this cannot be done and the engine is to remain unused longer than 30 days it must be prepared for storage DANGER NEVER STORE THE ENGINE WITH FUEL IN TANK INDOORS OR IN ANY ENCLOSED POORLY VENTILATED AREA WHERE FUEL VAPORS MIGHT REACH AN OPEN FLAME AS ON A FURNACE WATER HEATER DRYER ETC FIRE OR AN EXPLO SION COULD RESULT To prepare an engine for storage proceed as follows 1 Run the engine for about five minutes to warm it up a If gasohol was used drain the fuel tank then run the engine until it shuts down due to lack of fuel b Use of a good fuel stabilizer will prevent gum deposits from forming in the engine fuel system 2 While engine is still warm from running drain oil from crankcase and refill with new oil 3 Remove the spark plug and pour about 1 2 ounce 15ml of clean fresh engine oil into cylinder Crank the engine over slowly to distribute the oil Then install spark plug but do not connect the spark plug wire 4 Clean dirt oil grease etc from the engine 5 Store the engine in a clean dry area TUNE UP PROCEDURE Following is a minor tune up procedure When the proce dure has been completed either the engine will run properly
64. il it is gassing freely then take the specific gravity reading 3 Begin at one end of the battery and check the first cell using an automotive type battery hydrometer a Take two or three samples from the cell to stabilize the reading SECTION 6 ELECTRIC STARTERS AND BATTERIES b Once stabilized draw in the final sample c Draw in only enough electrolyte to obtain a reading do not let the hydrometer float hit the suction bulb d Hold the hydrometer vertically and shake it gently to make sure the float is not sticking to the inside of the glass barrel e Read and record the specific gravity reading 4 Check the temperature of the fluid Add the required points if temperature is above 80 F Subtract the required points if below 80 see Figure 6 3 LIQUID LEVEL Cell 5 Check and record readings of the remaining cells in the Same manner 6 When all cells have been checked subtract the lowest reading obtained from the highest reading If there is more than 30 points difference the battery is probably detec tive and should be replaced In Figure 6 3 the highest reading is 1 260 and the lowest reading is 1 225 Subtract 1 225 from 1 260 to obtain a 35 point difference Specific Gravity HIGH READING gt 35 POINTS DIFFERENCE wv LOW READING Figure 6 3 Using a Battery Hydrometer GENERAL In the course of tearing down a complete engine for ser vic
65. ine at high governed speed only when electrical loads are connected to the generator When the electrical loads are dis connected engine speed will automatically be reduced to idle OPERATING INSTRUCTIONS BEFORE START UP CAUTION Before cranking and starting the engine always set idle control switch to STOP Set the switch to its RUN position only after the engine has stabilized at high governed speed see Figure 4 1 ENGINE RUNNING To have the engine run at high governed speed only when electrical loads are connected and turned on set the idle con trol switch to ON The engine will decelerate to idle speed when loads are disconnected or turned off If you wish to have the engine run at high governed speed at all times with or without electrical loads connected set the idle control switch to OFF Figure 4 1 ON OFF Figure 4 1 Idle Control Switch STATOR POWER WINDINGS 000000 x 22 33 441 1 00902 44 0000 2 TRANSFORMER 156 8 oO CIRCUIT SWITCH BOARD COIL MAGNET 0000 A Schematic CIRCUIT OPERATION 1 With Idle Control switch set to ON a AC power is delivered from the generator s AC power windings to a circuit board for operation of the circuit board b With electrical loads connected to th
66. mbly and d the oil pickup assembly Cored oil passages are provided from the pickup bore to the pump and from the pump to the crankshaft bore INSPECTION Clean the cover and blow dry with compressed air Use com pressed air to blow out all oil passages Inspect the cover for cracks damage etc Check the crankshaft and camshaft bearing bore diameters as outlined in Section 11 GOVERNOR GEAR INSTALLATION 1 Apply engine oil to the governor gear shaft Figure 12 8 2 Install the governor gear thrust washer over the governor gear shaft followed by the governor gear assembly 3 Slide the governor retainer ring to a distance of 8mm down over the governor gear shaft 4 Lift the gear assembly up to the governor retainer ring 5 Install the spool over the shaft so that the flange is under the flyweights 6 Slide the governor gear assembly retainer ring and spool down the shaft until bottomed out SPOOL GOVERNOR FLYWEIGHTS RETAINER RING GOVERNOR GEAR ASSEMBLY GOVERNOR GEAR THRUST WASHER GOVERNOR GEAR SHAFT Figure 12 8 Governor Assembly CRANKCASE COVER INSTALLATION Install the crankcase cover as follows 1 Rest the crankcase on 15 side with the crankcase cover flange facing upward 2 Check that the valve tappets crankshaft and camshaft have been properly installed into the crankcase 49 SECTION 12 LUBRICATION 3 Make sure the timing marks on the crankshaft and
67. move the rocker arm cover see Figure 9 2 REMOVE ROCKER ARM COVER SCREWS Figure 9 2 Removal of Rocker Arm Cover 32 NOTE Whenever the rocker arm cover is removed the cover gasket must be replaced to ensure a proper seal 2 Loosen the rocker arm jam nuts on the pivot ball studs Then loosen the pivot ball studs Remove the two pivot ball studs rocker arms and jam nuts Also remove the push rod guide plate NOTE Keep intake and exhaust valve parts separated Intake and exhaust pivot ball studs rocker arms and push rods are identical However the wear patterns will be different u D PUSH ROD HF A GUIDE PLATE Figure 9 3 Rocker Arms and Push Rod Guide Plate 3 Remove the PUSH RODS see Figure 9 3 4 Remove the CYLINDER HEAD BOLTS then the CYLINDER HEAD and CYLINDER HEAD GASKET see Figure 9 4 NOTE Replace the cylinder head gasket every time the cylinder head is removed The new cylinder head gasket must be free of nicks and scratches as these could cause leaks CYLINDER CRANKCASE CYLINDER HEAD BOLTS CYLINDER HEAD GASKET Figure 9 4 Cylinder Head Removal TO PREVENT EYE INJURY ALWAYS WEAR EYE PRO WHEN REMOVING VALVE SPRINGS 5 Support the valves with your fingers while compressing the valve springs with your thumbs on the valve spring retainer see Figure 9 5 a With the spring compressed slide the larger hole
68. n of gum deposits during storage Add the stabilizer to the gasoline in the fuel tank or in the stor age container Follow the mix ratio recommended on the stabilizer container After adding the stabilizer to the engine fuel tank run the engine for about ten 10 minutes so it will enter the carburetor A brand name stabilizer can be purchased in most automotive repair facilities or in lawn and garden centers Carefully inspect the carburetor choke and throttle shafts for wear Grasp each shaft and attempt to move it horizon tally and vertically Maximum allowable end play for choke and throttle shafts is 0 004 inch 0 1mm Replace if exces sive play is evident ADJUSTABLE AND FIXED MAIN JET Some early production GN series engines were equipped with a carburetor having an adjustable main jet On later pro duction engines a carburetor with fixed main Jet is used 4 h z AT 1 Th Vas I k 2 Lak os ar bos 1 Nai pou mg i M 5 5 AA Pte M MIU LITE ap V L 22 Aa USE t UY Mes 7 Figure 2 5 Typical Carburetor with Choke SECTION 2 AIR CLEANERS AND CARBURETION CARBURETOR REMOVAL A choke style carburetor will already be loosened from its mount following step 5 in AIR CLEANER BOX REMOVAL on page 14 For primer style carburetor remove the two screw
69. ng the service plus common sense are major measures to prevent accidents The following definitions apply to DANGER WARNING CAU TION and NOTE blocks found throughout the manual DANGER After this heading you can read han Indicates a torque specification dling installing operating or servicing instructions that if not strictly complied with will result in per ndicates a measurement sonal injury Indicates a load specification WARNING After this heading you can read handling installing operating or servicing instructions that if not strictly complied with may result in personal Injury CAUTION After this heading you can read instruc tions for handing installing operating or servicing the engine that if not strictly complied with may result in damage to equipment and or property NOTE After this heading you can read explanatory statements that require special emphasis DIMENSIONS AND FEATURES PTO SIDE VIEW ELECTRIC STARTER OPTIONAL CON 10 0 39 DIMENSIONS AND FEATURES FRONT VIEW CYLINDER RUN STOP SWITCH LOW OIL SHUTDOWN INDICATOR Y E a lt 42 JN ENGINE NUM 106 I
70. omponents include the following Oil pickup assembly Oil pump Crankshaft oil seals e Pressure relief valve e Breather assembly e Crankcase cover Low oil pressure switch OIL FLOW See Figure 12 1 The oil pump draws crankcase oil through an oil pickup and delivers it to the areas requiring lubrication as follows 1 Through a cored channel in the crankcase cover and to the crankshaft journal at the power take off PTO end of the crankshaft 2 Through the hollow camshaft and to the camshaft bear ing at the flywheel end 3 Through a cored passage in the crankcase housing and to the crankshaft journal at the flywheel end 4 Through the crankshaft to the crankpin and connecting rod bearing Figure 12 1 Lubrication System Diagram 46 OIL PICKUP ASSEMBLY DESCRIPTION The oil pickup assembly consists of a plastic body and an oil pickup screen The pickup must be installed with its screen facing downward toward the crankcase base The tubular end of the pickup fits into a bore in the crankcase cover When the crankcase cover is installed a cast protrusion in the crankcase prevents the pickup from coming out OILPICKUP ASSEMBLY Figure 12 2 Oil Pickup Assembly INSPECTION Clean the pickup in solvent Inspect the plastic body for cracks or other damage Check the screen for damage Make sure the hollow pickup tube is clean and free of obs
71. on 15 STARTER CONTACTOR SYSTEM ll 26 CARBURETION emm rrr 15 HEAVY DUTY SWITCH SYSTEM 26 15 STARTER MOTOR OPERATING PRINCIPLES 26 Common Carburetor Problems 15 THE BENDIX DRIVE uuu u MERE Ce Ren 26 Adjustable and Fixed Main Jet aaa 15 STARTER MOTOR REPAIRS KK 26 27 Carburetor Removal 16 REMON AN seare 26 Carburetor Disassembly 16 Starter Motor MSG ON sessie 26 27 Cleaning and INSPECTION 16 TESTING THE STARTER MOTOR nen 2 Carburetor Installation 16 Checking the PINION 27 Tools for Starter Performance Test 27 SECTION 3 MECHANICAL GOVERNOR 18 20 Starter Performance 27 GOVERNOR OPERATION 18 BATTERY MAINTENANCE x 27 LPAR 18 27 GOVERNOR EXTERNAL PARTS 18 19 inspecting the Battery 27 Removal of Governor External Parts 18 19 Electrolyte Level i 21 Installation of Governor External Parts 19 TESTING A BATTERY Li 27 28 GOVERNOR GEAR SHAFT REPLACEMENT 19 Inspection 19 SECTION 7 COVERS AND SHROUDS 29 pectio RettioVal eser
72. or a worn wrist pin bore in the piston or rod NOTE Tolerances between the wrist pin and wrist pin bores are extremely close Always apply engine oil to the pin and its bores prior to installation 4 Check wrist pin and wrist pin bores for wear a Measure the outside diameter of the wrist pin b Measure the inside diameter of the wrist pin bore in piston c Measure the inside diameter of the wrist pin bore in con necting rod d Measure the wrist pin length 5 If excessive wear is found replace the worn part 5 WRIST PIN OUTSIDE DIAMETER GN 190 GN 191 GN 220 0 708 0 709 inch 17 989 18 000mm 3 WRIST PIN LENGTH GN 190 GN 191 GN 220 2 196 2 213 inch 55 8 56 2mm DIAMETER OF WRIST PIN BORE IN PISTON GN 190 GN 191 GN 220 0 708 0 709 inch 18 000 18 011mm DIAMETER OF WRIST PIN BORE IN ROD GN 190 GN 101 GN 220 0 709 0 710 inch 18 02 18 03mm PISTON RINGS GENERAL The following general rules pertaining to piston rings must always be complied with e Always replace piston rings in sets e Use a ring expander to remove or install piston rings or breakage could result Do not spread the rings too far apart or they might break e Use aring compressor when installing the piston into the cylinder e When installing NEW rings deglaze the cylinder walls with a commercially available deglazing tool DESCRIPTION A piston ring set consi
73. or repair the Models GN 190 GN 191 GN 220 horizontal shaft engines Applicable procedures are carefully explained and illustrated For exploded views and listings of engine parts refer to the Owner s Manual for the specific device on which the engine is used When ordering parts always include the model and serial number of the engine Be sure to insist on genuine Gen erac repair parts NOTE Engine Models GN 190RV GN 191RV and GN 220RV Engine block Part Numbers 86923 90993 and 90306 respectively are vertical shaft long blocks They are used in Generac s computer controlled variable speed RV generator set Service and repair information for these vertical shaft long blocks is not included in this manual For specific information on these engines refer to SERVICE MANUAL COMPUTER CONTROLLED VARI ABLE SPEED RV GENERATORS Part No 94468 A Small Frame Engines Engine Models GN 190 GN 191 and GN 220 are desig nated as small frame engines The CHART on Page 3 lists most engine models that were available at the time this manual was published Some of the differences between specific engine models listed in the CHART are as follows 1 Differences in the type of crankshaft a Some engine models may be equipped with a tapered crankshaft b Some models may have an unthreaded and keyed 3 4 or 1 inch crankshaft c A 5 8 inch diameter threaded crankshaft is used on some engines 2 Some engine models are equipped
74. or shaft Rotation of the governor shaft results in GOVERNOR LEVER and GOVERNOR ARM movement GOVERNOR ARM move ment moves the GOVERNOR ROD which in turn moves the CARBURETOR THROTTLE ARM Tension of the governor SPRING can be adjusted by means of the SPEED ADJUST NUT Figure 3 3 SPEED CONTROL ADJUST BRACKET SCREW L SPRING IDLE RE LEVER f GOVERNOR ji SHAFT GOVERNOR ROD AND ANTI LASH SPRING GOVERNOR LEVER CLAMP BOLT Figure 3 3 External Governor Parts Typical REMOVAL OF GOVERNOR EXTERNAL PARTS Before any covers and shrouds can be removed from the engine the governor external parts must be removed Refer to Figure 3 3 for the identification of the parts described in the following procedure 1 Remove the CAPSCREW from the IDLE CONTROL BRACKET 2 Loosen the GOVERNOR LEVER CLAMP BOLT 3 Loosen SPEED ADJUST SCREW and NUT until the GOVER NOR SPRING can be removed 4 the GOVERNOR LEVER from the GOVERNOR SHAFT 5 Disconnect the GOVERNOR ROD and ANTI LASH SPRING from the GOVERNOR LEVER Set the governor external parts aside INSTALLATION OF GOVERNOR EXTERNAL PARTS AFTER the installation of the engine shrouds and covers reinstall the governor external parts as follows refer to Figure 3 3 1 Reattach the GOVERNOR ROD and ANTI LASH SPRING to the GOVERNOR LEVER 2 Slide the GOVERNOR LEVER onto the GOVERNOR SHAFT 3 Tighten the GOVERNOR LEVER CLAMP BOLT
75. p the tester gap However loss of correct ignition timing may result in hard starting or no start ing at all 4 To determine if an engine miss is ignition related connect the spark tester in series with the high tension lead and the spark plug Figure 8 6 Then test the system as follows a Start the engine b If spark jumps the tester gap regularly but the miss con tinues the problem is in the spark plug or in the fuel system A spark miss will be readily apparent SPARK TESTER CLAMP CONNECTED TO SPARK PLUG SPARK TESTER SPARK PLUG BOOT LOW OIL INDICATOR Figure 8 6 Checking for Engine Miss NOTE The ignition system described in this section is typically used on horizontal shaft engines The ignition system used on all vertical shaft RV engines differs from that of horizontal shaft engines See SERVICE MANUAL COMPUTER CONTROLLED VARIABLE SPEED RV GENERATORS Manual Part No 94468 A SECTION 9 VALVE TRAIN MAJOR COMPONENTS Valve train components are shown in Figure 9 1 below DESCRIPTION Tappet Push Rod Intake Valve Exhaust Valve Valve Stem Seal Valve Spring Wear Washer Valve Spring Valve Spring Retainer Pivot Ball Stud Rocker Arm Rocker Arm Jam Nut Push Rod Guide Plate NA N Figure 9 1 Valve Train Components DISASSEMBLY 1 Remove the oil breather tube Remove the four M6 1 00 x 12mm screws Then re
76. piston This mark must face the flywheel end of crankshaft 3 00 position during reassembly MAJOR DIAMETER 2 753 2 754 in 69 939 69 959mm MINOR DIAMETER 2 747 2 748 in 69 789 69 809mm MEASURE AT A POINT 1 4 1 6 inches 35 5 40 5 mm FROM TOP OF PISTON Figure 10 3 Piston Major and Minor Diameter To check the piston for wear proceed as follows 1 Check the pistons MINOR DIAMETER a At a position directly in line with the wrist pin hole measure down from top of piston to a distance of 1 4 1 6 inches 35 5 40 5mm see Figure 10 3 b Measure at this point to check for wear If worn exces sively replace piston 2 Check the piston s MAJOR DIAMETER a At a point 90 from the wrist pin hole measure down trom top of piston to a distance of 1 4 1 6 inches 35 5 40 5mm see Figure 10 3 b Measure at this point to check for wear If wear is exces sive replace the piston PISTON MINOR DIAMETER GN 190 GN 191 GN 220 2 747 2 748 inches 69 789 69 809mm PISTON MAJOR DIAMETER GN 190 GN 101 GN 220 2 753 2 754 inches 69 939 69 959mm 3 Check wrist pin for looseness quick check wear in the wrist 0 wrist bore in piston wrist pin bore in rod is to check for looseness or play with the piston assembled to the rod b Looseness or play indicates a worn wrist pin
77. s PT EXTENSION 32 a 2 2 LL 2 HORI NIAL TAPER FMU2 sce 225712 tarer HURIZUNTAL SHAFI vire penen LINE 2 N 21862 019 20 748 lt N 4 000 0 157 3 970 0 156 Y I t n LONG 61 6 2 4 T 928 012 1 103 A 225 0 98 7 PP 928 012 1 103 H 928 000 1 102 GUAGE DIA Genes 928 000 1 102 NZ can 27 3 1 1 5 8 18 2 25 4mm LONG g 46 5 1 83 685 2 70 E 5 GUAGE LINE 5 g DIMENSIONS AND FEATURES CUTAWAY VIEWS Z BN gt 2721 NNNNNS Ek H 3 NZ z iz x Eg 5 A d P ag VL X SE A NC 37 2 Y WY Z m Z Z A Z EN Z 0 10 DESCRIPTION ITEM DESCRIPTION 1 CRANKCASE 12 PISTON PIN 2 CRANKCASE COVER 13 SNAP RING 3 CYLINDER HEAD 14 TAPPET 4 CRANKSHAFT 15 PUSH ROD 5 CAMSHAFT 16 OIL PUMP 6 ROCKER COVER BREATHER 17 CYLINDER HEAD GASKET 7 CONNECTING ROD 18 CRANKCASE COVER BOLT 8 PISTON RING SET 19 ROCKER COVER GASKET 9 OIL PICK UP ASSEMBLY 20 CYLINDER HEAD BOLT 10 CRANKCASE COVER GASKET 21 ROCKER COVER SCREW 11 PISTON 22 SPRING WASHER 4 CYCLE ENGINE T
78. s that hold it to the intake manifold being careful not to drop the lock nuts and washers on the opposite ends of the screws see Figure 2 6 The governor rod and lash spring must now be detached from the throttle rod on either style of carburetor Simply tilt the carburetor until the rod and spring can slip out of the hole on the lever GOVERNOR ROD AND ANTI LASH SPRING CARBURETOR LOCK NUT AND WASHER Figure 2 6 Removal of Primer Style Carburetor CARBURETOR DISASSEMBLY See Figure 2 7 The carburetor can be disassembled as follows 1 Remove the BOWL NUT Item 4 and the FIBER WASHER Item 5 Then remove the FLOAT BOWL Item 3 2 Remove the FLOAT PIN Item 7 Then remove the FLOAT Item 2 and INLET VALVE Item 8 3 Remove the IDLE SPEED SCREW Item 18 along with SPRING Item 17 4 Rotate the THROTTLE VALVE Item 14 to its closed posi tion and remove the SCREW Item 13 The THROTTLE VALVE can now be removed 5 Remove the THROTTLE SHAFT Item 15 along with the THROTTLE SHAFT SPRING Item 12 and the THROTTLE SHAFT SEAL Item 11 CLEANING AND INSPECTION 1 Separate out all nonmetallic parts Then clean metallic parts with solvent or commercial carburetor cleaner DO NOT ALLOW NONMETALLIC PARTS TO CONTACT SOLVENT 2 Inspect the THROTTLE SHAFT Item 15 and THROTTLE VALVE Item 10 Replace if damaged 3 Inspect the IDLE JET Item 16 Check the p
79. s with engine oil Seal protectors should be used to prevent damage to oil seals during installation Install the crankshaft as follows 1 Lubricate all bearing surfaces with engine oil 2 Install the valve tappets 3 Support both ends of the crankshaft and carefully install into the crankcase 4 Rotate the crankshaft until the timing mark Figure 11 10 is toward the cam gear side of the crankcase Figure 11 10 Timing Mark on Crankshaft Gear 45 SECTION 11 CRANKSHAFT AND CAMSHAFT NOTE If the crankshaft gear is spun on the crankshaft the timing will be off If this happens the crankshaft must be replaced CAMSHAFT INSTALLATION Apply oil to camshaft bearing and to bearing bore in crankcase Install the camshaft and spring washer into the crankcase camshaft bore Hold the valve tappets out of the way during installation NOTE Make sure the spring washer is in position Figure 11 12 Align the timing mark on the camshaft gear with the timing mark on the crankshaft gear Figure 11 11 The piston must be at top dead center TDC NOTE For installation of the oil pump oil pickup and crankcase cover see Section 12 LUBRICATION Figure 11 12 Position of Spring Washer SECTION 12 LUBRICATION GENERAL The engine lubrication system serves a reduce friction between moving parts b cool the engine and c estab lish a negative pressure in the crankcase to prevent oil seal leakage Major c
80. sts of a a top compression ring b a second compression ring and c an oil ring assembly 39 SECTION 10 PISTON RINGS AND ROD The OIL CONTROL RING a three piece assembly consisting of two oil rails and an oil spacer ring Oil rails have a rounded and may be installed with either side up The SECOND COMPRESSION RING has an inside chamfer This chamfer must face upward when installing the ring The TOP COMPRESSION RING has a barrel shaped and can be installed with either side facing up PISTON CUTAWAY VIEW TOP COMPRESSION RING EITHER SIDE UP 2ND COMPRESSION RING CHAMFER FACING UP OIL CONTROL RING EITHER SIDE UP Figure 10 4 Location of Rings Piston Grooves RING END GAP Inside the cylinder locate a point that is 2 75 inches 7Omm down from the top of the cylinder about halfway down Place ring into cylinder and use the piston to push the ring down to the stated depth Check ring end gap with a feeler gauge See Figure 10 5 If the ring end gap is excessive the cylinder is worn exces sively See next page for ring gap tolerances TOP RING END GAP GN 190 GN 191 GN 220 0 005 0 016 inch 0 15 0 40mm SECOND RING END GAP GN 190 GN 191 GN 220 0 006 0 016 inch 0 15 0 40mm OIL RING END GAP GN 190 GN 191 GN 220 0 015 0 055 inch 0 38 1 40mm NOTE Oversize pistons and rings are
81. t is held open by engine oil pressure during cranking and running Should engine oil pressure drop below approximately 10 psi for any reason the switch contacts will dose With the switch contacts closed the following will occur A low oil pressure indicator will turn on and glow as power is available for its operation e Switch contacts closure will connect the primary ignition circuit to ground ignition will terminate and the engine will shut down NOTE Some differences may exist between low oil pressure systems Refer to the electrical schematic wiring diagram in the Owners Manual for the specific application using this engine SECTION 12 LUBRICATION Figure 12 15 Low Switch Without Optional Oil Filter TORQUE 9 foot pounds or 108 inch pounds TORQUE SPECIFICATION LOW OIL SWITCH TORQUE SPECIFICATION OIL FILTER ADAPTER BOLT TORQUE 9 foot pounds 108 inch pounds LOW OIL SWITCH Figure 12 14 Low Oil Switch With Optional Oil Filter 51 SECTION 13 TROUBLESHOOTING PROBLEM SOLVING INTRODUCTION Problems that affect engine operation may be classified as one of or a combination of two or more of the following Engine will not start e Engine starts with difficulty e Engine lacks power e Engine vibrates e Engine overheats e Engine burns oll In many cases the cause of a problem will be readily appar ent If this is not the case check engine compression as well
82. t lbs 264 in Ibs 22 ft lbs 264 in lbs Connecting Rod Bolts 10 ft lbs 120 in Ibs 10 ft lbs 120 in Ibs 10 ft lbs 120 in Ibs Flywheel Nut 75 ft lbs 900 in Ibs 75 ft lbs 900 in lbs 75 ft lbs 900 in Ibs Crankcase Cover Bolts 8 ft lbs 100 in Ibs 18 ft lbs 216 in lbs 18 ft lbs 216 in Ibs Ignition Coil Bolts 5 ft lbs 60 in Ibs 5 ft lbs 60 in lbs 5 ft lbs 60 in Ibs Spark Plug 13 ft lbs 156 in lbs 13 ft lbs 156 in Ibs 13 ft lbs 156 in lbs Rewind Starter Screws 5 ft lbs 60 in Ibs 5 ft lbs 60 in Ibs 5 ft lbs 60 in Ibs Starter Motor Bolts 18 ft lbs 216 in Ibs 18 ft lbs 216 in lbs 18 ft lbs 216 in lbs Intake Manifold Screws 4 ft lbs 50 in Ibs 4 ft lbs 50 in Ibs 4 ft lbs 50 in Ibs Carburetor to Intake Manifold 3 3 ft lbs 40 in lbs 3 3 ft lbs 40 in lbs 3 3 ft lbs 40 in lbs Air Cleaner Box to Carburetor 4 ft lbs 50 in Ibs 4 ft lbs 50 in Ibs 4 ft lbs 50 in Ibs Blower Housing Screws 7 ft lbs 84 in lbs 7 ft lbs 84 in lbs 7 ft lbs 84 in Ibs Upper and Lower Shroud Screws A ft lbs 48 in lbs A ft lbs 48 in Ibs 4 ft lbs 48 in lbs Governor Lever Clamp Bolt 5 8 ft lbs 70 in lbs 5 8 ft lbs 70 in lbs 5 8 ft lbs 70 in lbs Oil Filter Adapter Bolts 9 ft lbs 108 in Ibs 9 ft lbs 108 in lbs 9 ft lbs 108 in lbs
83. tion of Oil Pump Drive Pins 12 Carefully install the crankcase cover Align the cover with dowel pins on the crankshaft flange as well as with the crankshaft and camshaft Make sure the cover gasket is on Rotate the crankshaft to align the oil pump inner and outer rotors The cover should fall easily into place DO NOT FORCE 13 Install the crankcase cover bolts and tighten see Figure 12 11 TORQUE SPECIFICATION CRANKCASE COVER BOLTS GN 190 TORQUE 8 foot pounds or 100 inch pounds TORQUE SPECIFICATION CRANKCASE COVER BOLTS GN 191 and GN 220 TORQUE 18 foot pounds or 216 inch pounds Figure 12 11 Crankcase Cover Bolt Tightening Sequence 14 After tightening the crankcase cover bolts make sure the crankshaft turns freely OPTIONAL OIL FILTER The optional oil filter is a spin on type An oil filter adapter is bolted to the oil filter pad When installing the oil filter coat the filter seal with engine oil Then install the filter and tighten until its seal contacts the filter adapter After the filter seal contacts the adapter tighten 3 4 to 1 turn more See Figure 12 12 OIL FILTER ADAPTER GASKET OIL FILTER ADAPTER OIL FILTER PAD OIL FILTER ADAPTER BOLT OIL FILTER Section 12 12 Optional Oil Filter LOW OIL PRESSURE SYSTEM Some engine applications may be equipped with a low oil pressure switch See Section 12 10 The switch is a normally closed type bu
84. tructions OIL PUMP DESCRIPTION The oil pump Figure 12 3 is of the gerotor type Its inner rotor rotates on a shaft provided in the camshaft bore of the crankcase cover The outer rotor is installed over two drive pins on the end of the camshaft and is driven by camshaft rotation TO CRANKCASE COVER E OUTER Figure 12 3 Pump PUMP CONTINUED INSPECTION 1 Inspect the inner and outer rotors for damage and wear Figure 12 4 2 Use a feeler gauge to check tip clearance of inner rotor with rotor installed on shaft in crankcase cover 3 Measure the bore inner diameter of the inner rotor 4 Measure the inner rotor thickness 5 Check the outer rotor outside diameter 6 Inspect the outer rotor drive pins on the camshaft Check for breaking bending or other damage The two roll pins can be removed and replaced with relative ease Replace any oil pump component that is damaged or worn excessively NOTE The shaft on which the inner oil pump rotor rotates is NOT replaceable If the shaft is damaged or worn the crankcase cover must be replaced Tip Clearance of Rotor Inner Rotor Outer Rotor O D Figure 12 4 Inner and Outer Rotor Check Points OIL PUMP INNER ROTOR SHAFT O D DESIGN DIAMETER 0 353 0 354 inch 8 969 8 987mm 47 SECTION 12 LUBRICATION 222 OIL PUMP ROTOR TIP CLEARANCE
85. with automatic idle control other models are not 3 Some models may have an oil filter others may not be so equipped Long Block The term long block refers to a basic engine which does not include such items as a blower housing air cleaner car buretor etc Figure 1 1 shows a typical engine long block Figure 1 2 shows a typical complete engine Engine 1 0 Number Serial Number The part number and serial number of the engine long block can be found on a nameplate located on the engine crankcase see Figure 1 3 SECTION 1 GENERAL GENERAC CORPORATION B ENG IDENT No EHC 0U995 U Figure 1 3 Location of Part and Serial Numbers SECTION 1 GENERAL ENGINE CARE RECOMMENDED FUELS Use clean fresh UNLEADED regular grade gasoline Unleaded gasoline burns cleaner extends engine life and promotes easier starting by reducing combustion chamber deposits The use of gasohol is NOT recommended If gaso hol must be used it should contain not more than 10 percent ethanol If gasohol containing ethanol is used special care is required when preparing the engine for storage see Stor age Instructions DO USE GASOLINE CONTAINING METHANOL DO MIX OIL WITH THE GASOLINE DANGER GASOLINE IS EXTREMELY FLAMMABLE AND ITS VAPORS ARE EXPLOSIVE DO NOT PERMIT SMOKING OPEN FLAME OR HEAT IN THE VICINITY WHILE HANDLING GASOLINE AVOID SPILLAGE OF GASOLINE ON A HOT ENGINE COMPLY WITH ALL LAWS P

Service And Repair Manual For Small Frame GN

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