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4-1

SECTION 4: GOVERNOR CONTROLS AND GOVERNOR

MECHANICAL GOVERNOR

DISASSEMBLE:

1.  Drain the oil from the engine. 

2.  Remove any rust, nicks, or burrs from the crankshaft.

3.  Remove the four (4) oil cooler screws.

4.  Disconnect the wiring from the oil pressure switch.

5.  Remove the governor lever from the shaft.

6.  Separate the ball joint on the swinging arm.

7.  Remove all of the crankcase bolts and slide the crankcase 

cover off.

8.  Discard the crankcase gasket & oil passage o-ring.

GOVERNOR

Both the spool and the flyweights must move freely for the governor 
to work properly.  Check for wear on the spool and flyweights.  If 
wear is noticed, change the governor gear assembly (gear and fly-
weights), spool, and governor arm.  Lubricate all moving parts when 
reassembling.

GOVERNOR REMOVAL AND INSTALLATION:

1.  Leverage gear assembly and governor spool off of governor 

shaft.

GOVERNOR GEAR ASSEMBLY

GOVERNOR 

SPOOL

OIL

PASSAGE

O-RING

Figure 4-1. Governor Gear Assembly and Spool

2.  Remove any remaining plastic from the notch in the governor 

shaft.

3.  Check that all the governor bearing parts (top plate, bearing, 

and bottom plate) are on the shaft, and that it moves smoothly. 
(See Figure 4-2)

4.  Slide the new gear assembly and spool onto the governor shaft.  

Slide until the gear hooks into the notch in the governor shaft. 
(See Figure 4-2)

SPOOL

GOVERNOR SHAFT

ROLLER BEARING PLATES

ROLLER BEARING

GOVERNOR GEAR AND
FLYWEIGHT ASSEMBLY

GOVERNOR ASSEMBLY

SPOOL MUST ENGAGE UNDER BOTH FLYWEIGHTS

CUPPED SIDE OF BEARING FACES DOWN

AWAY FROM GEAR

PRESS THIS END INTO BLOCK

(37 mm / 1.456” EXPOSED SHAFT)

37 mm

Figure 4-2. Governor Assembly and Components

 4

Содержание GTH1000

Страница 1: ...ENGINE SERVICE MANUAL A I R C O O L E D E N G I N E S OHVI V Twin Engine MODELS GTH760 990 1000 GTV760 990 1000...

Страница 2: ...f and advise the service trade of all conceivable procedures or methods by which a service might be performed nor of any pos sible hazards and or results of each procedure or method We have not undert...

Страница 3: ...PISTON RINGS AND CONNECTING ROD INSPECTION AND ASSEMBLY SECTION 13 ENGINE ASSEMBLY SECTION 14 SPECIFICATIONS 1 TABLE OF CONTENTS ATTENTION Generac Power Systems does not approve or authorize the use...

Страница 4: ...the engine The engine can operate safely effi ciently and reliably only if it is properly operated and maintained Many accidents are caused by failing to follow simple and funda mental rules or precau...

Страница 5: ...while the engine is running Never work on this engine or handle any electrical device while standing in water while barefoot or while hands or feet are wet DANGEROUS ELECTRIC SHOCK will result Allow...

Страница 6: ...r BDC both the intake and exhaust valves are closed As the piston moves upward toward TDC the fuel air mixture becomes compressed Just before the piston reaches TDC ignition occurs C IGNITION AND POWE...

Страница 7: ...ailored for the season in which the engine will be operated LUBRICATION Oil has four purposes It cools cleans seals and lubricates During normal operation small particles of metal from the cylinder wa...

Страница 8: ...ilter lightly oil filter gasket with fresh clean engine oil Screw filter on by hand until gasket contacts filter adapter Tighten 3 4 to one full turn farther Figure 1 5 Start and run engine at idle fo...

Страница 9: ...ar quickly As the rings and cylinder bore become worn these abrasive particles enter the crankcase and contaminate the oil forming an abrasive mixture which will cause wear on all of the internal movi...

Страница 10: ...l 2 Is the fuel stale 3 Is the tank vent open 4 Is the fuel shutoff valve open 5 Is the fuel pump working 6 Is the fuel solenoid working CHECK IGNITION If spark does not occur look for Shorted ignitio...

Страница 11: ...RESSION It has been determined through testing that a simple and accurate indication of compression can be made as follows Remove both spark plugs and insert a compression gauge into either cylinder o...

Страница 12: ...at appears to be a problem with engine operation such as hard starting vibration etc may be the fault of the equipment rather than the engine itself Listed are the most common effects of equipment pro...

Страница 13: ...voltage drop A continuous tone indicates continuity shorted diode An incomplete circuit open diode will be displayed as OL Figure 2 1 Digital Multimeter 1 Insert RED test lead into receptacle in mete...

Страница 14: ...ith a shop towel 3 Remove rotating screen and blower housing 4 Disconnect ground wire s at ignition coil s 5 Remove ignition coil screws and remove ignition coil s See Figure 2 5 Note The flywheel doe...

Страница 15: ...flywheel see Figure 2 9 FLYWHEEL REMOVE FLYWHEEL 1 Remove two screws that attach fan and fan retainer to flywheel 2 Remove fan retainer and fan 3 Loosen flywheel nut until it is flush with end of cran...

Страница 16: ...d crankshaft taper removing all oil dirt or grease 1 Insert flywheel key into crankshaft 2 Align keyways and assemble flywheel to crankshaft Figure 2 11 Torquing Flywheel Nut Figure 2 12 Installing Fl...

Страница 17: ...3 2 Vertical Shaft Carburetor 6 Remove the four nuts holding the carburetor and plenum to the intake manifold see Figure 3 6 7 Remove the plenum carburetor and gaskets from the manifold and discard t...

Страница 18: ...off solenoid when removing the plunger CARBURETOR INSTALLATION VERTICAL SHAFT 1 Slide new carburetor gasket and carburetor onto the studs 2 Slide new plenum gasket and plenum onto the studs 3 Install...

Страница 19: ...hold throttle lever against idle stop screw 11 Adjust the idle stop screw to maintain 1800 RPM idle 12 Slowly move speed control lever to high speed position 13 With the speed control in the high spe...

Страница 20: ...is attached to the valve and extends to the bottom of the storage tank Pressure in the tank forces liquid propane through the tube when the valve is opened The Generac LP system starts with a pressure...

Страница 21: ...sealing gaskets they should be lubricated using an O ring lubricant DO NOT RE USE O RINGS For improving the functional features and lifetime of the solenoid it is recommend that the gaskets and filte...

Страница 22: ...ws 10 32 x 0 630 and lift the cover off the regulator body and secondary diaphragm see Figure 3 13 The cover has a tendency to stick to the diaphragm and gasket A slight tap on the edge of the cover w...

Страница 23: ...ifice for nicks scratches or uneven wear IMPORTANT If the primary or secondary seats show any of the above mentioned conditions the regulator is not rebuildable and must be replaced 5 Lay the regulato...

Страница 24: ...indentation of the valve Apply slight downward pressure and with a gentle rotary motion swivel the valve into flat contact with the orifice These valve inserts are not sold separately but are crimped...

Страница 25: ...secondary seat See Figure 3 27 Figure 3 27 Check Secondary Seat for Leaks 16 Turn off the air supply Install the secondary diaphragm by hooking the secondary lever through the center pin If the screw...

Страница 26: ...Figure 3 31 20 Install the regulator a Clean all threaded areas and use a commercially available pipe sealant Make sure sealant does not get inside of the regulator b Connect LP line s reconnect batte...

Страница 27: ...bricate all moving parts when reassembling GOVERNOR REMOVAL AND INSTALLATION 1 Leverage gear assembly and governor spool off of governor shaft GOVERNOR GEAR ASSEMBLY GOVERNOR SPOOL OIL PASSAGE O RING...

Страница 28: ...upper bushing is pressed in ASSEMBLE GOVERNOR ARM 1 Slide the thrust washer part way onto the new governor arm 2 Insert the governor arm in the lower bushing holder and slide it part way in 3 Install...

Страница 29: ...osition torque the clinching screw to 11 3 Nm 100 in lbs 4 Check to make sure that the throttle travels from WOT to IDLE If it doesn t the governor needs to be reset again CLINCHING SCREW ID L E W O T...

Страница 30: ...GOVERNOR Figure 4 8 Dynamic Governor Adjustment Vertical Shaft SPEED CONTROL LEVER ALLEN WRENCH Figure 4 9 Dynamic Governor Adjustment Horizontal Shaft HIGH SPEED SCREW Figure 4 10 Dynamic Governor A...

Страница 31: ...ove spark plugs 1 Remove the parts depicted in Figure 5 2 a Discard gaskets and valve cover seals REMOVE ROCKER ARMS 1 Unlock jam nuts and remove two ball studs and rocker arm assemblies see Figure 5...

Страница 32: ...hort section of rubber fuel line under valves inside combustion chamber to hold valve in place while compressing spring 2 Hold down valve spring retainer with a valve spring compressor Figure 5 5 Remo...

Страница 33: ...e seats may be reconditioned using a valve seat cutter If valve seat is wider than dimension shown in Figure 5 9 a narrowing cutter should be used to ensure that contact area of valve seat is centered...

Страница 34: ...13 b Lubricate inner top lip of valve stem seal with oil Figure 5 13 Install Valve Stem Seals 2 Install valves Figure 5 14 Note Lightly coat valve stems with oil before installing valves Be sure lubri...

Страница 35: ...stroke a Adjust rocker arms and check clearance Figure 5 17 Valve Clearance cold Intake and Exhaust 0 076 mm 003 b Torque jam nut to 19 Nm 168 in lbs Figure 5 17 Adjust Valve Clearances 2 Set No 2 cyl...

Страница 36: ...Nm 40 in lbs b If engine is equipped with finger screws tighten screws by hand to approximately 1 3 Nm 12 in lbs 8 Assemble air cleaner 9 Make Static and Dynamic Governor adjustments as outlined on P...

Страница 37: ...ors e Dirty or worn starter motor commutator bearing weak magnets etc f Worn brushes or weak brush spring g Wrong oil viscosity for temperature expected h Battery leads too long or wire too small i Ba...

Страница 38: ...other accessories turned off measure the battery voltage across the battery posts using a VOM set to the 20 Volt scale Do not measure across the the battery wire terminal ends Voltage should read 12...

Страница 39: ...Manual STARTER CONTACTOR STARTER MOTOR TACHOMETER 12 VOLT BATTERY CLAMP ON AMP METER VISE Figure 6 5 Testing Starter Motor Performance Some equipment manufacturers may use a constant drive pump which...

Страница 40: ...itch are the same switch disconnect wires from spark plugs and ground ignition using two Ignition Testers Turn switch to START Meter should display 9 volts or more while cranking engine If less than 9...

Страница 41: ...6 5 SECTION 6 ELECTRIC STARTER 6 FEMALE PACKARD CONNECTOR FUSE Figure 6 8 Vertical Shaft Figure 6 9 FEMALE PACKARD CONNECTOR FUSE Figure 6 10 Horizontal Shaft Figure 6 11...

Страница 42: ...OID WHITE 4 LOW OIL PRESSURE SWITCH BROWN 5 OPEN 1 2 3 4 5 LEGEND 1 LOW OIL PRESSURE SWITCH BROWN 2 IGNITION KILL TERMINAL YELLOW 3 OPEN 4 CARBURETOR FUEL SOLENOID WHITE 5 STARTER SOLENIOD ORANGE WIRE...

Страница 43: ...IL PRESSURE SP SPARK PLUG SM STARTER MOTOR IC IGNITION COIL SUPPLIED BY CUSTOMER WHITE WHITE AC OUTPUT AC OUTPUT DC OUTPUT FS FS FUEL SHUTOFF SOLENOID CONNECT TO IGNITION GROUND WIRE TO GROUND IGNITIO...

Страница 44: ...NOTES 6 8...

Страница 45: ...wires as shown in Figure 7 1 Meter test clip leads may be attached to either AC output terminal 5 With the engine running at 3600 RPM output should be no less than 26 Volts AC 6 If no or low output i...

Страница 46: ...g is greater than when the engine is stopped the charging system is working CHARGING SYSTEM REGULATOR VOLTAGE BATTERY STATOR SUPPLIED BY B STARTER STUD CUSTOMER WHITE WHITE AC AC B Figure 7 3 Basic Ch...

Страница 47: ...ote Some engine models have a normally closed type switch and will work the opposite as above A delay built into the shutdown system on some engine applications allows oil pressure to build during sta...

Страница 48: ...ilter Change the oil and filter after the first eight 8 hours of operation Change the oil and oil filter every 100 hours thereafter If you are using this engine under dirty or dusty conditions or in e...

Страница 49: ...e lubrication system see Figure 8 6 PRESSURE RELIEF VALVES When a constant displacement pump is used a relief valve is neces sary to relieve the build up of pressure in the system Relief valves are ne...

Страница 50: ...LIEF VALVE 60 psi COMMON PRESSURE RELIEF VALVE 40 psi CAP RELIEF BALL RELIEF SPRING The components of both pressure relief valves are identical The difference in pressure is determined by the depth of...

Страница 51: ...re 9 2 Note If necessary place the engine flywheel side down to prevent tappets from catching on the camshaft a Remove tappets Note Remove any carbon or ridge at the top of the cylinder bores to preve...

Страница 52: ...over sump Figure 9 4 Remove Crankshaft Note Clean all surfaces of gasket material Remove oil seals and thoroughly clean components in solvent Organize components keeping parts which are assemblies tog...

Страница 53: ...tch ensures proper lubrication and piston ring break in Refer to Cylinder Finish Cross Hatch for correct procedure for cross hatch honing RESIZING Note Oversize rings and pistons are NOT available DO...

Страница 54: ...mportant that the entire cylinder and crankcase be thor oughly cleaned after honing First wash the cylinder and crankcase carefully in a commercial solvent or kerosene Then thoroughly wash cylinder an...

Страница 55: ...oil seal and press it in until it is 1 5mm 1 16 below the mounting surface CHECK CAMSHAFT BEARINGS Use a telescoping gauge and caliper to check camshaft bearings If camshaft bearings are worn crankca...

Страница 56: ...LINDER CRANKCASE COVER 10 4 CLAMP THIS END IN VISE MATERIAL WOOD 25 4mm 1 x 216mm 8 5 x 254mm 10 0 12mm 0 473 TYP 17mm 0 67 16 5mm 0 65 183 5mm 7 224 10 5mm 0 413 216mm 8 504 254mm 10 0 Figure 10 10 H...

Страница 57: ...aft reject sizes in Section 14 FLYWHEEL KEY OIL GALLERY OIL GALLERIES CRANKPIN PTO JOURNAL MAGNETO JOURNAL TIMING GEAR Figure 11 1 Check Crankshaft CHECK CAMSHAFT Inspect gear teeth lobes and journals...

Страница 58: ...NOTES...

Страница 59: ...is a slip fit in piston and connecting rod Keep pistons and connecting rods together as an assembly Do not mix CHECKING PISTON AND RINGS If the cylinder is not going to be replaced and the piston show...

Страница 60: ...PISTON PIN BEARING Figure 12 7 Check Rod Bearings ASSEMBLE PISTON AND CONNECTING ROD Lubricate parts with engine oil and assemble 1 piston and connect ing rod Figure 12 8 1 Notch or casting mark on t...

Страница 61: ...er a Install lower oil scraper ring a Install upper oil scraper ring 2 Install center compression ring with dimple up 3 Install top compression ring with dimple up CASTING MARK MUST FACE FLYWHEEL SIDE...

Страница 62: ...NOTES...

Страница 63: ...ve connecting rod cap 2 Lubricate cylinder bores and crankpin and rotate crankshaft until it is at bottom of stroke 3 Install 1 piston with notch or casting mark towards flywheel side See Figure 13 3...

Страница 64: ...SAGE O RING Figure 13 6 Crankcase Oil Passage O ring INSTALL OIL PUMP 1 Lubricate inner and outer gerotor and set in place 2 Install oil pump cover 3 Torque screws to 12 2 Nm 108 in lbs See Figure 13...

Страница 65: ...ew to hold coil in place 4 Repeat for second coil Note The spark plug lead must be at the top 5 Install ground wire onto tab terminal on ignition coils Important Make sure wires are routed over coil m...

Страница 66: ...d coil INSTALL CYLINDER HEADS 1 Install cylinder head with new gasket 2 Lubricate threads of head bolts with one drop of oil a Torque head bolts in sequence shown Figure 13 14 to 29 9 Nm 22 ft lbs 3 I...

Страница 67: ...rance Figure 13 16 Valve Clearance cold INTAKE and EXHAUST 0 076mm 0 02mm 003 001 b Torque ball stud jam nuts to 19 Nm 168 in lbs 2 Repeat for No 2 cylinder 3 Install valve covers with new gaskets Fig...

Страница 68: ...n lbs 6 Install blower housing a Torque screws to 4 5 Nm 40 in lbs 7 Install rotating screen a Torque screws to 1 9 Nm 17 in lbs 8 Install intake manifold assembly a Torque bolts to 19 Nm 168 in lbs 9...

Страница 69: ...s 19 Nm 168 in lbs Flywheel Nut 214 Nm 150 ft lbs Flywheel Fan Retainer Bolts 21 7 Nm 182 in lbs Governor Lever clinching screw 11 3 Nm 100 in lbs Intake Manifold Screws 19 Nm 168 in lbs Oil Pump Cove...

Страница 70: ...9 39 01 mm 1 535 1 536 38 96 mm 1 534 Magneto Journal 38 00 38 012 mm 1 496 1 4965 37 85 mm 1 490 PTO Journal 42 00 42 012 mm 1 6535 1 654 41 85 mm 1 648 CAMSHAFT Magneto Journal PTO Journal 17 964 17...

Страница 71: ...NOTES...

Страница 72: ...NOTES...

Страница 73: ......

Страница 74: ...C 1 888 436 3722 generac com Part No 0F6923 Printed in USA Rev D 10 24 12 2012 Generac Power Systems Inc All rights reserved Specifications are subject to change without notice No reproduction allowed...

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