Service And Repair Manual For Small Frame GN

TABLE OF CONTENTS

DIMENSIONS AND FEATURES ............................ 3-7

4-CYCLE ENGINE THEORY ...................................... 8

SECTION 1: GENERAL ...................................... 9-12

PURPOSE AND SCOPE OF MANUAL ................................ 8

SMALL FRAME ENGINES .................................................. 8

LONG BLOCK .................................................................. 8

ENGINE I.D. NUMBER/SERIAL NUMBER ............................ 8

ENGINE CARE ................................................................ 10

Recommended Fuels .................................................. 10

Recommended Engine Oil .......................................... 10

Change Oil Filter ........................................................ 10

STORAGE INSTRUCTIONS .............................................. 10

TUNE-UP PROCEDURE .............................................. 10-11

OVERSIZE PARTS ............................................................ 12

SECTION 2: AIR CLEANERS AND CARBURETION 14-17

AIR CLEANER ................................................................ 14

Servicing .................................................................... 14

Foam Pre-Cleaner ...................................................... 14

Paper Filter ................................................................ 14

Air Cleaner Box Removal ............................................ 14

Air Cleaner Box Installation ........................................ 15

CARBURETION .............................................................. 15

General...................................................................... 15

Common Carburetor Problems .................................. 15

Adjustable and Fixed Main Jet .................................... 15

Carburetor Removal .................................................. 16

Carburetor Disassembly.............................................. 16

Cleaning and Inspection ............................................ 16

Carburetor Installation .............................................. 16

SECTION 3: MECHANICAL GOVERNOR.......... 18-20

GOVERNOR OPERATION ................................................ 18

GOVERNOR INTERNAL PARTS ........................................ 18

GOVERNOR EXTERNAL PARTS .................................. 18-19

Removal of Governor External Parts ...................... 18-19

Installation of Governor External Parts........................ 19

GOVERNOR GEAR SHAFT REPLACEMENT ...................... 19

Inspection .................................................................. 19

Removal .................................................................... 19

Installation ................................................................ 19

LINKAGE INSTALLATION ................................................ 19

GOVERNOR ADJUSTMENT ........................................ 19-20

Initial Adjustment.................................................. 19-20

Running Adjustment .................................................. 20

SECTION 4: OPTIONAL IDLE CONTROL .......... 22-23

GENERAL ...................................................................... 22

OPERATING INSTRUCTIONS............................................ 22

Before Start-up .......................................................... 22

Engine Running.......................................................... 22

CIRCUIT OPERATION ...................................................... 22

IDLE CONTROL ADJUSTMENT ........................................ 23

General...................................................................... 23

Initial Adjustment ...................................................... 23

Final Adjustment ........................................................ 23

SECTION 5: REWIND STARTERS...................... 24-25

GENERAL ...................................................................... 24

REWIND ASSEMBLY REMOVAL ...................................... 24

DISASSEMBLY (OLD STYLE) ............................................ 25

REASSEMBLY.................................................................. 25

DISASSEMBLY (NEW STYLE)............................................ 25

SECTION 6: ELECTRIC STARTERS AND BATTERIES ..26-28

INTRODUCTION ............................................................ 26

STARTER CONTACTOR SYSTEM...................................... 26

HEAVY DUTY SWITCH SYSTEM ...................................... 26

STARTER MOTOR OPERATING PRINCIPLES ...................... 26

THE BENDIX DRIVE ........................................................ 26

STARTER MOTOR REPAIRS ........................................ 26-27

Starter Motor Removal .............................................. 26

Starter Motor Installation ...................................... 26-27

TESTING THE STARTER MOTOR ...................................... 27

Checking the Pinion .................................................. 27

Tools for Starter Performance Test .............................. 27

Starter Performance Test ............................................ 27

BATTERY MAINTENANCE .............................................. 27

General...................................................................... 27

Inspecting the Battery ................................................ 27

Electrolyte Level ........................................................ 27

TESTING A BATTERY ................................................ 27-28

SECTION 7: COVERS AND SHROUDS .................. 29

GENERAL ...................................................................... 29

Installation of Covers and Shrouds ............................ 29

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SECTION 8: IGNITION SYSTEM ...................... 30-31

GENERAL ...................................................................... 30

MAJOR COMPONENTS .................................................. 30

IGNITION COIL ASSEMBLY.............................................. 30

SPARK PLUG .................................................................. 30

FLYWHEEL ................................................................ 30-31

Checking Flywheel Magnet ........................................ 30

Flywheel Key .............................................................. 30

Flywheel Removal ................................................ 30-31

Flywheel Installation .................................................. 31

TESTING THE IGNITION SYSTEM .................................... 31

SECTION 9: VALVE TRAIN .............................. 32-36

MAJOR COMPONENTS .................................................. 32

DISASSEMBLY .......................................................... 32-33

VALVE SERVICE .............................................................. 33

Valve ..........................................................................33

Valve Seats ................................................................ 33

Valve Guides .............................................................. 34

Valve Tappets ............................................................ 34

Valve Springs.............................................................. 34

INSTALLATION .......................................................... 34-35

ADJUSTING VALVE CLEARANCE .................................... 36

INSTALL ROCKER ARM COVER ........................................36

SECTION 10: PISTON, RINGS AND ROD ........ 38-41

GENERAL ...................................................................... 38

REMOVAL ...................................................................... 38

PISTON .................................................................... 38-39

Removal from Connecting Rod .................................. 38

Check Piston for Wear .......................................... 38-39

PISTON RINGS ................................................................ 39

General...................................................................... 39

Description ................................................................ 39

Ring End Gap........................................................ 39-40

CONNECTING ROD ........................................................ 40

ASSEMBLY AND INSTALLATION ................................ 40-41

Assembly .................................................................. 40

Installation ................................................................ 41

CYLINDER SERVICE ........................................................ 41

Inspection .................................................................. 41

Reboring the Cylinder ................................................ 41

SECTION 11: CRANKSHAFT AND CAMSHAFT 42-45

CAMSHAFT REMOVAL .................................................. 42

Removal of Crankcase Cover...................................... 42

Camshaft Removal .................................................... 42

CRANKSHAFT REMOVAL................................................ 42

CAMSHAFT INSPECTION ................................................ 43

CRANKSHAFT INSPECTION........................................ 43-44

Crankshaft Proper ...................................................... 43

Crankshaft Sleeve Bearing.......................................... 44

COMPRESSION RELEASE .......................................... 44-45

CRANKSHAFT INSTALLATION ........................................ 45

CAMSHAFT INSTALLATION ............................................ 45

SECTION 12: LUBRICATION ............................ 46-50

GENERAL ...................................................................... 46

OIL FLOW ...................................................................... 46

OIL PICKUP ASSEMBLY .................................................. 46

Description ................................................................ 46

Inspection .................................................................. 46

OIL PUMP ................................................................ 46-47

Description ................................................................ 46

Inspection .................................................................. 47

CRANKSHAFT OIL SEALS ................................................ 47

PRESSURE RELIEF VALVE ................................................ 48

Description ................................................................ 48

Inspection .................................................................. 48

BREATHER ASSEMBLY .................................................... 48

Description ................................................................ 48

Inspection .................................................................. 48

CRANKCASE COVER ................................................ 48-50

Description .......................................................... 48-49

Inspection .................................................................. 49

Governor Gear Installation ........................................ 49

Crankcase Cover Installation ................................ 49-50

OPTIONAL OIL FILTER...................................................... 49

LOW OIL PRESSURE SYSTEM .................................... 49-50

SECTION 13: TROUBLESHOOTING ................ 52-53

SPECIFICATIONS .............................................. 54-59

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