Generac Power Systems OHVI GSH 190 Service Manual Download Page 29

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SeCTIoN 6: CYlINder HeAd ANd vAlveS

6-5

ALLEN

WRENCH

JAM

NUT

Figure 6-17. Tightening Rocker Arm Jam Nut

INSTAll roCker ArM Cover

. Using a new rocker arm cover gasket, install the rocker

arm cover and retain with four screws (see Figure 6-8).

2. Tighten each screw to 20 in-lbs (2.2 Nm) working diago-

nally from corner to corner as shown in Figure 6-9.

. Repeat the same pattern, this time tightening each

screw to 8 in-lbs (5. Nm). DO NOT EXCEED this torque
value.

. Install oil breather tube.

ROCKER
COVER
GASKET

ROCKER
COVER

SCREW

Figure 6-18. Install Rocker Cover

Figure 6-19. Tightening Pattern for

Rocker Arm Cover Screws

0C1103Arev0.indd 5

6/22/2006 10:50:51 AM

Summary of Contents for OHVI GSH 190

Page 1: ......

Page 2: ...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 procedure or method We have not under...

Page 3: ...cifications Large Frame Engines Table of contents A Word About Special Tools Many of the procedures depicted in this manual require the use of special tools Some of the tools required are available as...

Page 4: ...te safely efficiently and reliably only if it is properly operated and maintained Many accidents are caused by fail ing to follow simple and fundamental rules or precautions Generac cannot possibly an...

Page 5: ...ipment This engine requires an adequate flow of cooling air for its continued proper operation Never operate the equipment inside any room or enclosure where the free flow of cooling air into and out...

Page 6: ...er BDC both the intake and exhaust valves are closed The piston moves upward toward TDC and the fuel air mixture is compressed Just before the piston reaches TDC ignition occurs C ignition and Power B...

Page 7: ...izes gum deposits and also will ensure fuel volatility tailored for the season in which the engine will be operated Lubrication Oil has four purposes It cools cleans seals and lubricates During normal...

Page 8: ...Restart engine and check for oil leaks Figure 1 2 Oil Drain Figure 1 3 Oil Filter Replace Spark Plugs Replace spark plugs every 100 hours of operation or every season whichever occurs first Replace s...

Page 9: ...ssion This check up performed in a systematic manner can usually be done in a matter of minutes It is the quickest and surest method of determining the cause of failure The basic check up procedure is...

Page 10: ...es 6 Rings 7 Piston 8 Cylinder Equipment Affecting Engine Operation Frequently what appears to be a problem with engine opera tion such as hard starting vibration etc may be the fault of the equipment...

Page 11: ...ug The spark plug should be cleaned and regapped periodically The plug should be replaced every 100 hours of operation or once annually whichever comes first Set spark plug gap to 0 030 inch 0 76mm Fi...

Page 12: ...gh tension lead to the tester terminal 3 Crank the engine rapidly If spark jumps the gap of the spark tester you may assume the ignition system is operat ing satisfactorily Figure 2 5 Testing Ignition...

Page 13: ...cessary 3 Remove the paper filter 4 Clean the paper filter by tapping gently on a flat surface If it is very dirty replace it 5 Clean the air cleaner cover Then install the foam pre cleaner into the c...

Page 14: ...ing 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...

Page 15: ...th Do NOT attempt to remove this tube Tube movement will adversely affect carburetor metering characteristics Carburetor Reassembly Reassemble the carburetor in the reverse order of disassem bly The f...

Page 16: ...1 Bowl Gasket 7 1 Float Pin 8 1 Inlet Valve 9 1 Fuel Inlet 10 1 Cap Screw 11 1 Throttle Shaft Felt Washer 12 1 Throttle Shaft Spring 13 1 Screw 14 1 Throttle Valve 15 1 Throttle Shaft 16 1 Idle Jet 1...

Page 17: ...er 6 1 Bowl Gasket 7 1 Fuel Inlet Valve 8 1 Float Pin 9 1 Main Jet 10 1 Choke Shaft Seal 11 1 Choke Shaft 12 1 Choke Plate 13 2 Choke Plate Screw 14 1 Throttle Shaft 15 1 Throttle Shaft Seal 16 2 Thro...

Page 18: ...output leads Read the AC output frequency in HERTZ cycles per second If the engine is used in some other application pressure washer pump air compressor etc use a tachometer to read the engine rpm 1 S...

Page 19: ...a a thrust washer b governor gear assem bly c snap ring d governor spool and e governor ARM A lock pin and washer retain the governor arm in the crankcase cover The governor gear assembly houses the...

Page 20: ...the GOVERNOR LEVER 2 Slide the GOVERNOR LEVER onto the GOVERNOR ARM 3 Tighten the GOVERNOR LEVER CLAMP BOLT 4 Reinstall the GOVERNOR SPRING to the GOVERNOR LEVER and SPEED ADJUST SCREW then tighten th...

Page 21: ...justment can be accomplished with the engine running Proceed as follows NOTE For AC generator applications disconnect or turn OFF all electrical loads For non generator applications turn OFF the equip...

Page 22: ...clockwise richer until rpm or frequency starts to drop off 2 Turn the main jet clockwise leaner until rpm or frequency again starts to decrease 3 Turn the main jet counterclockwise richer until the be...

Page 23: ...rical loads connected to the generator cur rent will flow through the primary windings of a sensing transformer A proportional voltage and current will then be induced into the transformer s secondary...

Page 24: ...z 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 If necessary back the carburet...

Page 25: ...igure 6 2 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 st...

Page 26: ...o a 45 angle After reconditioning the valves should be lapped with a suitable valve lapping tool and valve lapping compound see Figure 6 6 Figure 6 6 Valve NOTE Proper lapping of valves and seats will...

Page 27: ...e valve stem Note Be sure to lubricate valve stems and valve guides before assembly 2 The intake valve has a valve stem seal a Install the intake valve stem seal b Install the valve spring washer the...

Page 28: ...its compres sion stroke both valves closed Adjust valve clearance as follows 1 Loosen the rocker arm jam nut Use an allen wrench to turn the pivot ball stud while checking the clearance between rocker...

Page 29: ...ur screws see Figure 6 18 2 Tighten each screw to 20 in lbs 2 24 Nm working diago nally from corner to corner as shown in Figure 6 19 3 Repeat the same pattern this time tightening each screw to 48 in...

Page 30: ...NOTES...

Page 31: ...ring loaded starter dogs engage the pulley and the engine is cranked When the rope is allowed to return the starter dogs disen gage from the pulley Recoil assembly removal The rewind starter assembly...

Page 32: ...and SPRING KEEPER into the HOUSING Install SPRING STARTER DOGS and DOG SPRINGS 3 Install retainer PAWL and SCREW 4 Wind the pulley counterclockwise until tight generally three to four turns Then allo...

Page 33: ...mature This sleeve has large spiral threads on its surface that match the pinion gear s internal threads The sleeve turns with the armature and the pinion gear rotates on the threads to move outward o...

Page 34: ...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 until it is gass...

Page 35: ...ricate the camshaft bearing at the opposite end of the camshaft 4 Oil from the end of the camshaft enters a cored passage and flows to one crankshaft bearing and one balancer bearing 5 Oil flows throu...

Page 36: ...ody for cracks or other damage Check the pickup screen for damage or clogging Make sure the hollow tube is free of obstructions Install the two o ring seals prior to reassembly Replace the oil pickup...

Page 37: ...ief Valve DESCRIPTION A ball type pressure relief valve is located in a bore of the crankcase cover see Figure 9 7 The valve serves to limit oil pressure to a maximum value The ball will remain agains...

Page 38: ...series engines is mounted on the crankcase assem bly and is configured differently See SERVICE MANUAL COMPUTER CONTROLLED VARIABLE SPEED RV GENERA TORS Manual Part No 094468 A ROCKER ARM COVER CHECK...

Page 39: ...crankcase cover flange facing upward 2 Install the valve tappets crankshaft connecting rod assem bly camshaft and balancer as described in Section 11 3 Make sure the timing marks on the crankshaft ca...

Page 40: ...crankcase 3 Make sure the timing marks on the crankshaft and cam shaft gears are properly aligned See Figure 9 15 4 Place the crankcase cover gasket onto the crankcase flange 5 Apply engine oil to th...

Page 41: ...13 Install the crankcase cover bolts and torque see Figure 9 16 Refer to Section 14 for torque specifications Figure 9 16 Crankcase Cover Bolt Tightening Sequence 14 After tightening the crankcase co...

Page 42: ...the following will occur A low oil pressure indicator will turn on and glow as power is available for its operation The closure of the switch contacts will connect the primary ignition circuit to grou...

Page 43: ...r shroud see Figure 10 1 5 Remove the two capscrews from the upper shroud see Figure 10 1 NOTE The blower housing is notched at the point where the governor rod and anti lash spring pass through it Th...

Page 44: ...Notes...

Page 45: ...s up and clear of the camshaft lobes Then remove the camshaft both tappets and the inner and outer oil pump rotors Note Some models may be equipped with a camshaft spring washer 3 Remove the balancer...

Page 46: ...NT SUCH AS KEROSENE 4 Carefully measure the diameters of the crankpin crank shaft journal at flywheel end and the crankshaft journal at PTO end Replace the crankshaft if it is worn beyond the stated r...

Page 47: ...ds 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 Measure th...

Page 48: ...d between the camshaft and crankcase see Figure 11 13 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 CRAN...

Page 49: ...ne 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 is slightly elliptical...

Page 50: ...ING UP Figure 12 4 Location of Rings in Piston Grooves DESCRIPTION A piston ring set consists of a a top compression ring b a second compression ring and c an oil ring assembly The OIL CONTROL RING is...

Page 51: ...then through the rod and the second piston bore until it contacts the snap ring f Finally install the second snap ring to retain the wrist pin in the piston and rod bores INSTALLATION 1 Coat the cyli...

Page 52: ...inder for dirty broken or cracked cooling fins 2 Check cylinder wall for wear scoring or other damage 3 Check all bearing surfaces for wear scoring or other damage REBORING THE CYLINDER At the time th...

Page 53: ...till will not start remove and inspect the spark plug If the plug is WET look for the following 1 Overchoking 2 Dirty air cleaner 3 Excessively rich fuel air mixture 4 Water in the fuel 5 Fuel leaking...

Page 54: ...ect clearance f Engine is overloaded f Reduce excessive load 3 Engine misses under load a Incorrect spark plug a Install correct spark plug b Spark plug is fouled b Replace spark plug c Spark plug por...

Page 55: ...8 Cylinder walls worn 8 Replace crankcase 9 Piston rings and or grooves worn 9 Install new rings and or piston 10 Oil passages obstructed 10 Clean out oil passages 9 Crankshaft oil seal leaks 1 Crank...

Page 56: ...Notes...

Page 57: ...STEM DIAMETER 0 215 0 216 inch 5 465 5 480mm 0 2348 0 2354 inch 5 965 5 980mm 0 2348 0 2354 inch 5 965 5 980mm EXHAUST VALVE STEM DIAMETER 0 214 0 215 inch 5 445 5 460mm 0 234 0 2346 inch 5 945 5 960m...

Page 58: ...bearing Crankcase Cover Assembly MODEL GN 190 GN 191 GN GSH 220 CRANKSHAFT BEARING BORE 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 CAM...

Page 59: ...GROOVE WIDTH 0 059 0 061 inch 1 52 1 54mm 0 059 0 061 inch 1 52 1 54mm 0 059 0 061 inch 1 52 1 54mm SECOND RING GROOVE WIDTH 0 059 0 061 inch 1 52 1 54mm 0 059 0 061 inch 1 52 1 54mm 0 059 0 061 inch...

Page 60: ...220 PUMP TIP 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 0 025mm INNER ROTOR BORE 0 354 0 355 inch 9 000 9 019mm 0 354 0 355 inch 9 000 9 019mm...

Page 61: ...in lbs 10 8 Nm 96 in lbs Spark Plug 20 3 Nm 180 in lbs 20 3 Nm 180 in lbs 20 3 Nm 180 in lbs Rewind Starter Screws 10 8 Nm 96 in lbs 10 8 Nm 96 in lbs 10 8 Nm 96 in lbs Starter Motor Bolts 24 4 Nm 21...

Page 62: ...14 6 Notes...

Page 63: ...6 980 mm 0 274 0 275 inch 6 965 6 980 mm EXHAUST VALVE STEM DIAMETER 0 273 0 274 inch 6 945 6 960 mm 0 273 0 274 inch 6 945 6 960 mm 0 273 0 274 inch 6 945 6 960 mm TAPPET DIAMETER INTAKE AND EXHAUST...

Page 64: ...RANKSHAFT BEARING BORE DIAMETER 1 380 1 381 inch 35 065 35 090 mm 1 380 1 381 inch 35 065 35 090 mm 1 380 1 381 inch 35 065 35 090 mm CAMSHAFT BEARING BORE DIAMETER 1 299 1 300 inch 33 00 33 03 mm 1 2...

Page 65: ...0 061 inch 1 530 1 555 mm 0 060 0 061 inch 1 530 1 555 mm 0 060 0 061 inch 1 530 1 555 mm SECOND RING GROOVE WIDTH WIDTH 0 060 0 061 inch 1 530 1 555 mm 0 060 0 061 inch 1 530 1 555 mm 0 060 0 061 in...

Page 66: ...0 982 0 983 inch 24 96 24 98 mm MAIN BALANCER BEARING DIAMETER PTO END 0 982 0 983 inch 24 96 24 98 mm 0 982 0 983 inch 24 96 24 98 mm 0 982 0 983 inch 24 96 24 98 mm Oil pump MODEL GN 320 GN 360 GN...

Page 67: ...Ignition Coil Bolts 9 5 Nm 84 in lbs 9 5 Nm 84 in lbs 9 5 Nm 84 in lbs Spark Plug 20 3 Nm 180 in lbs 20 3 Nm 180 in lbs 20 3 Nm 180 in lbs Rewind Starter Screws 6 8 Nm 60 in lbs 6 8 Nm 60 in lbs 6 8...

Page 68: ...15 6 Section 15 specifications Large Frame Engines...

Page 69: ...15 7 Section 15 specifications Large Frame Engines 15...

Page 70: ...Notes...

Page 71: ......

Page 72: ...Generac Power Systems Inc P O Box 310 Eagle WI 53119 Part No 0C1103A Printed in USA Revision A 06 20 06...

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