iii
TESTING PROCEDURE ............................................................................................................................... 67
SERVICE ....................................................................................................................................................... 68
SPARK PLUG SERVICE ............................................................................................................................... 68
CONDITIONS CAUSING FREQUENT SPARK PLUG FOULING ................................................................. 68
IGNITION TIMING PROCEDURE ................................................................................................................. 68
SERVICE TIPS .............................................................................................................................................. 71
CHAPTER 9 INTERNAL ENGINE AND CYLINDER .................................................................................... 72
GENERAL INFORMATION ............................................................................................................................ 72
OPERATION .................................................................................................................................................. 72
4-CYCLE ENGINE THEORY ......................................................................................................................... 72
LUBRICATION SYSTEMS............................................................................................................................. 73
COUNTERBALANCE SYSTEMS .................................................................................................................. 73
COMPONENTS ............................................................................................................................................. 74
ENGINE OPERATION PROBLEMS .............................................................................................................. 75
TESTING ....................................................................................................................................................... 77
ENGINE KNOCKS ......................................................................................................................................... 77
ENGINE OVERHEATS .................................................................................................................................. 77
SURGES OR RUNS UNEVENLY .................................................................................................................. 77
ENGINE MISFIRES ....................................................................................................................................... 77
ENGINE VIBRATES EXCESSIVELY ............................................................................................................. 78
BREATHER PASSING OIL............................................................................................................................ 78
EXCESSIVE OIL CONSUMPTION................................................................................................................ 78
LACKS POWER............................................................................................................................................. 78
SERVICE ....................................................................................................................................................... 79
DISASSEMBLY PROCEDURE...................................................................................................................... 79
CYLINDERS .................................................................................................................................................. 81
CYLINDER HEADS ....................................................................................................................................... 82
PISTONS, RINGS AND CONNECTING RODS ............................................................................................ 82
CRANKSHAFTS AND CAMSHAFTS ............................................................................................................ 84
VALVES ......................................................................................................................................................... 85
CRANKCASE BREATHERS.......................................................................................................................... 86
CYLINDER COVER, OIL SEAL, AND BEARING SERVICE ......................................................................... 87
CRANKSHAFT BEARING SERVICE............................................................................................................. 88
COUNTERBALANCE SERVICE.................................................................................................................... 89
FLYWHEEL SERVICE ................................................................................................................................... 89
CHAPTER 10 ENGINE SPECIFICATIONS................................................................................................... 90
FOUR CYCLE TORQUE SPECIFICATIONS................................................................................................. 91
ENGINE SPECIFICATIONS STANDARD POINT IGNITION......................................................................... 93
SOLID STATE AND EXTERNAL IGNITION .................................................................................................. 97
CHAPTER 11 EDUCATION MATERIALS AND TOOLS............................................................................. 102
DECIMAL / FRACTION CONVERSIONS .................................................................................................... 105
SEARS CRAFTSMAN CROSS REFERENCE SUPPLEMENT INCLUDED IN BACK OF BOOK