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
