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Table Of Contents - Generac Power Systems GTH760 Service Manual

Ohvi v-twin engine

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Service manual (74 pages)

Table Of Contents

Table of Contents

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Table of Contents

Table Of Contents3

Rules For Safe Operation4

Before Operating4

While Operating5

Service Information5

4-Cycle Engine Theory6

Ignition And Power6

Maintenance Schedule7

Recommended Oil Type7

Section 1: General Information7

Change Oil Filter8

Oil Fill/Check Vertical Engine8

Cleaning Intake Screen8

Replace Spark Plugs9

Service Canister Air Cleaners9

Air Cleaner Maintenance9

Service Dual Element Air Cleaners9

Troubleshooting10

Check Ignition10

Engine Running10

Systematic Check10

Section 2: Ignition10

Cylinder Balance Test11

Check Compression11

Cylinder Leak Down Test Procedure11

Cylinder Leakdown Test11

Equipment Affecting Engine Operation12

Hard Starting Or Will Not Start12

Things Which Affect Both Cylinder12

Engine Won't Stop12

Engine Wiring Harness13

Testing Ground Wires13

Digital Multimeter13

Diode Failure Diagnosis13

Wire Harness Check14

Ignition Coil Testing14

Removing And Installing Wire Harness14

Ground Wire Routing15

Adjust Ignition Coil Air Gap15

Remove Flywheel15

Adjusting Air Gap15

Removing Flywheel16

Torquing Flywheel Nut16

Check Flywheel And Crankshaft16

Installing Flywheel And Fan16

Carburetor Types17

Carburetor Removal17

Horizontal Shaft17

Vertical Shaft Carburetor17

Section 3: Carburetion And Fuel System17

Carburetor Cleaning18

Carburetor Installation19

Fuel Pump Assembly20

Testing The Fuel Shut Off Solenoid21

Disassembly And Assembly Of Ipg Solenoid Valve21

Testing And Pairing Vaporizer/Regulator21

Remove Five Secondary Cover Screws22

Remove Regulator And Disassemble As Follows22

Lift Edge Of Diaphragm22

Reassembly Of Regulator23

Remove Secondary Lever And Spring23

Remove/Replace Two Screws 8-32 X 0.375" Long23

Remove Primary Diaphragm23

Install Primary Spring, Primary Cover And Screws24

Positioning Secondary Lever Valve25

Primary Pressure Test Port Opening25

Check Primary Pressure Reading25

Check Secondary Seat For Leaks25

Install Secondary Diaphragm26

Install Secondary Cover26

Check Outlet Port26

Re-Install Pipe Plug In Test Opening26

Typical Lp (Liquid) System27

Mechanical Governor29

Governor Gear Assembly And Spool29

Governor Removal And Installation29

Section 4: Governor Controls And Governor29

Governor Arm Assembly30

Crankcase Bolt Torque Sequence30

Static Governor Adjustment31

Dynamic Governor Adjustment31

Static Governor Adjustment (Later Version)31

Dynamic Governor Adjustment (Earlier Version)31

Remove Cylinder Heads33

Remove Rocker Arms33

Section 5: Cylinder Head And Valves33

Disassemble Cylinder Head34

Remove Cylinder Head34

Removing Retainers34

Removing Valve Stem Seals34

Inspect And Repair35

Reface Valves And Seats35

Check Cylinder Head Distortion35

Valve Seat Dimensions35

Install Valve Stem Seals36

Measure Valve Stem Diameter36

Check Valve Springs36

Install Valves36

Compress Valve Spring And Install Keepers37

Adjust Valve Clearances37

General Assembly38

Engine Will Not Crank39

Starter Motor Spins But Does Not Crank Engine39

Starter Motor Spins But Will Not Stop39

Engine Cranks Slowly39

Section 6: Electric Starter39

Test Starter Motor40

Checking Starter Voltage Drop40

Testing Starter Solenoid40

Testing Starter Voltage Drop40

Starter Amp Draw Test41

Battery Information41

Testing Starter Motor Performance41

Typical Battery41

Checking Battery42

Testing Battery42

Battery Recommendations42

Battery Cable Recommendations42

Vertical Shaft43

20 Amp Regulated Alternator47

Alternator Output Test47

Testing Dc Output Charging Wire47

Testing Ac Output47

Section 7: Alternators47

Basic Charging System Schematic48

Amp Alternator48

Protection Systems49

Checking The Engine Oil Level49

Engine Protective Devices49

Low Oil Pressure Switch49

Changing The Engine Oil And Filter50

Oil Drain Location50

Oil Change Procedure50

Removal Of Oil Filter50

Section 8: Lubrication System50

Pressure Relief Valves51

Oil Pump, Horizontal Engine51

Typical V-Twin Engine Oil Flow (Vertical Shaft Engine Shown)52

Partial View Of Engine Breakdown53

Section 9: Engine Disassembly53

Remove Camshaft54

Remove Oil Pump (Vertical Shaft Engine)54

Remove Pistons And Connecting Rods54

Remove Oil Pump (Horizontal Shaft Engine)54

Check Crankcase55

Checking Cylinder Head Mounting Surface55

Check Cylinder Bore55

Cylinder Finish (Cross Hatch)55

Section 10: Cylinder And Crankcase Cover55

Cylinder Cross Hatch56

Honing Cylinders56

Check Magneto (Flywheel End) Bearing56

Check Pto Bearing57

Check Camshaft Bearings57

Install Pto Oil Seal57

Honing Fixture58

Check Crankshaft:59

Check Camshaft:59

Section 11: Crankshaft And Camshaft59

Disassemble Piston And Connecting Rod61

Checking Piston And Rings61

Check Ring Grooves61

Checking Ring End Gap62

Check Piston Pin Bore62

Check Piston Pin62

Check Rod Bearings62

Assemble #1 Rod And Piston63

Assemble #2 Rod And Piston63

Piston Ring Installation63

Install Crankshaft65

Compressing Rings65

Installing Piston And Connecting Rod65

Torque Connecting Rods65

Section 13: Engine Assembly65

Installing Camshaft66

Crankcase Oil Passage O-Ring66

Rotating Governor Shaft66

Installing Oil Pump66

Crankcase Screw Torque Sequence67

Install Alternator67

Install Coils67

Install Breather67

Torque Flywheel Nut68

Adjust Air Gap68

Install Cylinder Head68

Install Rocker Arms68

Adjust Valve Clearance69

Install Valve Covers And Gaskets69

Install Blower Housing69

Ground Terminal70

General Specifications71

Common Specifications71

Torque Specifications71

Section 14: Specifications71

Standard And Reject Dimensions72

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