Tecumseh 3-11HP 4-Cycle L-Head Engines Technician's Handbook

This manual covers engine models: ECV100 - 120, H22 - 80, HH40 - 70, HHM80, HM70 - 100, HMSK70 - 110, HMXL70, HS40 - 50, HSK30 - 70, HSSK40 - 50, HT30 - 35, HXL35, LAV30 - 50, LEV80 - 120, TNT100 - 120, TVM125 - 220, TVXL170 - 220, TVS75 - 120, TVXL105 - 115, V40 - 80, VH40 - 70, V60 - 70, VM70 - 100 Model numbers are located on the engine shroud. 3 TO 11 HP 4-CYCLE L-HEAD ENGINES T E C H N I C I A N ’ S H A N D B O O K TECUMSEH

i C Tecumseh Products Company 1998 CONTENTS CHAPTER 1 GENERAL INFORMATION ......................................................................................................... 1 ENGINE IDENTIFICATION ............................................................................................................................... 1 INTERPRETATION OF MODEL NUMBER ...................................................................................................... 1 SHORT BLOCKS .............................................................................................................................................. 2 FUEL ................................................................................................................................................................. 2 ENGINE OIL ..................................................................................................................................................... 3 TUNE-UP PROCEDURE .................................................................................................................................. 3 STORAGE ........................................................................................................................................................ 4 CHAPTER 2 AIR CLEANERS ........................................................................................................................ 5 GENERAL INFORMATION ............................................................................................................................... 5 OPERATION ..................................................................................................................................................... 5 COMPONENTS ................................................................................................................................................ 5 TROUBLESHOOTING OR TESTING .............................................................................................................. 5 SERVICE .......................................................................................................................................................... 6 DISASSEMBLY PROCEDURE ......................................................................................................................... 6 POLYURETHANE-TYPE FILTER ELEMENT ................................................................................................... 6 PAPER-TYPE FILTER ELEMENT .................................................................................................................... 6 CHAPTER 3 CARBURETORS AND FUEL SYSTEMS ................................................................................... 7 GENERAL INFORMATION ............................................................................................................................... 7 OPERATION ..................................................................................................................................................... 8 FUEL PRIMERS ............................................................................................................................................... 8 IMPULSE FUEL PUMPS .................................................................................................................................. 9 FLOAT STYLE CARBURETORS ..................................................................................................................... 9 DIAPHRAGM (PRESSURE DIFFERENTIAL) CARBURETORS ..................................................................... 9 COMPONENTS .............................................................................................................................................. 10 CARBURETOR IDENTIFICATION ................................................................................................................. 11 DUAL SYSTEM CARBURETORS .................................................................................................................. 11 SERIES 1 CARBURETORS ........................................................................................................................... 11 SERIES 3 & 4 CARBURETORS ..................................................................................................................... 11 DIAPHRAGM CARBURETORS ..................................................................................................................... 11 SERIES 6 CARBURETORS 4-CYCLE ........................................................................................................... 12 SERIES 8 ........................................................................................................................................................ 12 SERIES 9 ........................................................................................................................................................ 12 SERIES 10 (EMISSION) ................................................................................................................................. 12 NON-TECUMSEH CARBURETORS -- DELLORTO CARBURETOR ........................................................... 12 ENGINE TROUBLESHOOTING CHART ....................................................................................................... 13 CARBURETION TROUBLESHOOTING CHART ........................................................................................... 14 TESTING ........................................................................................................................................................ 15 SERVICE ........................................................................................................................................................ 15 CARBURETOR PRE-SETS AND ADJUSTMENTS ....................................................................................... 15 FINAL ADJUSTMENTS (NON-EMISSION ENGINES) .................................................................................. 16 NON-ADJUSTABLE CARBURETOR ............................................................................................................. 16 DISASSEMBLY PROCEDURE ....................................................................................................................... 17 FLOAT STYLE CARBURETORS ................................................................................................................... 17 DIAPHRAGM CARBURETORS ..................................................................................................................... 19 FLOAT ADJUSTING PROCEDURE ............................................................................................................... 19 INSPECTION .................................................................................................................................................. 20 ASSEMBLY ..................................................................................................................................................... 21 STANDARD SERVICE CARBURETORS ....................................................................................................... 24 CHAPTER 4 GOVERNORS AND LINKAGE ................................................................................................. 26 GENERAL INFORMATION ............................................................................................................................. 26 OPERATION ................................................................................................................................................... 26 INTERNAL COMPONENTS (VARIOUS STYLES) ......................................................................................... 26 TROUBLESHOOTING .................................................................................................................................... 26 ENGINE OVERSPEEDING ............................................................................................................................ 27 ENGINE SURGING ........................................................................................................................................ 27 SERVICE ........................................................................................................................................................ 27 GOVERNOR ADJUSTMENT .......................................................................................................................... 27 GOVERNOR ADJUSTMENT PROCEDURE FOR SHORT BLOCK INSTALLATIONS ................................. 27

ii GOVERNOR GEAR AND SHAFT SERVICE ................................................................................................. 28 SPEED CONTROLS AND LINKAGE ............................................................................................................. 29 CHAPTER 5 REWIND STARTERS ................................................................................................................ 35 GENERAL INFORMATION ............................................................................................................................. 35 OPERATION ................................................................................................................................................... 35 COMPONENTS .............................................................................................................................................. 35 SERVICE ........................................................................................................................................................ 35 ROPE SERVICE ............................................................................................................................................. 35 RETAINER REPLACEMENT .......................................................................................................................... 36 STYLIZED REWIND STARTER (TVS, HM, TVM, TVXL), AND STAMPED STEEL STARTER (HM, VM, TVM, TVXL) ............................................................................................................................... 36 STYLIZED REWIND STARTER WITH PLASTIC RETAINER ........................................................................ 37 STANDARD STAMPED STEEL AND CAST ALUMINUM STARTER (HM, VM) ............................................ 38 VERTICAL PULL STARTER HORIZONTAL ENGAGEMENT TYPE .............................................................. 39 VERTICAL PULL STARTER VERTICAL ENGAGEMENT TYPE ................................................................... 40 CHAPTER 6 ELECTRICAL SYSTEMS ....................................................................................................... 42 GENERAL INFORMATION ............................................................................................................................. 42 OPERATION ................................................................................................................................................... 42 STARTING CIRCUIT AND ELECTRIC STARTERS ....................................................................................... 42 CHARGING CIRCUIT ..................................................................................................................................... 42 CONVERTING ALTERNATING CURRENT TO DIRECT CURRENT ............................................................ 43 HALF WAVE RECTIFIER SINGLE DIODE .................................................................................................... 43 FULL WAVE RECTIFIER BRIDGE RECTIFIER ............................................................................................. 43 COMPONENTS .............................................................................................................................................. 43 BATTERY ........................................................................................................................................................ 43 WIRING ........................................................................................................................................................... 43 ELECTRICAL TERMS .................................................................................................................................... 44 BASIC CHECKS ............................................................................................................................................. 45 TROUBLESHOOTING ELECTRICAL STARTER CIRCUIT FLOW CHART .................................................. 46 TROUBLESHOOTING ELECTRICAL CHARGING CIRCUIT FLOW CHART ............................................... 47 TESTING PROCEDURE ................................................................................................................................ 48 STARTING CIRCUIT ...................................................................................................................................... 48 CHARGING CIRCUIT ..................................................................................................................................... 48 VOLTAGE REGULATIONS ............................................................................................................................. 56 LOW OIL SHUTDOWN SWITCHES ............................................................................................................... 56 SERVICE ........................................................................................................................................................ 57 12 VOLT OR 120 VOLT ELECTRIC STARTERS WITH EXPOSED SHAFT ................................................. 57 12 VOLT D.C. OR 120 VOLT A.C. ELECTRIC STARTERS WITH THE STARTER GEAR UNDER THE CAP ASSEMBLY ............................................................................................................................... 57 INSPECTION .................................................................................................................................................. 58 CHAPTER 7 FLYWHEEL BRAKE SYSTEMS ............................................................................................... 59 GENERAL INFORMATION ............................................................................................................................. 59 OPERATION ................................................................................................................................................... 59 BOTTOM SURFACE SYSTEM ....................................................................................................................... 59 INSIDE EDGE SYSTEM ................................................................................................................................. 60 COMPONENTS .............................................................................................................................................. 60 SERVICE ........................................................................................................................................................ 61 FLYWHEEL REMOVAL .................................................................................................................................. 61 BRAKE LEVER AND PAD .............................................................................................................................. 61 IGNITION GOUNDOUT TERMINAL ............................................................................................................... 61 STARTER INTERLOCK SWITCH .................................................................................................................. 62 CONTROL CABLE .......................................................................................................................................... 62 BRAKE BRACKET REPLACEMENT .............................................................................................................. 62 CHAPTER 8 IGNITION .................................................................................................................................. 63 GENERAL INFORMATION ............................................................................................................................. 63 OPERATION ................................................................................................................................................... 63 SOLID STATE IGNITION SYSTEM (CDI) ...................................................................................................... 63 MAGNETO IGNITION SYSTEM (POINTS) .................................................................................................... 63 IDENTIFICATION OF TECUMSEH IGNITION SYSTEMS ............................................................................. 64 COMPONENTS .............................................................................................................................................. 64 IGNITION TROUBLESHOOTING .................................................................................................................. 66

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

1 CHAPTER 1 GENERAL INFORMATION ENGINE IDENTIFICATION Tecumseh engine model, specification, and serial numbers or (date of manufacture, DOM) are stamped into the blower housing or located on a decal on the engine in locations as illustrated (diag. 1 & 2). NOTE: On some LEV engines, a cover bezel must be removed to provide access to the identification decal (diag. 1). The engine identification decal also provides the applicable warranty code and oil recommendations (diag. 3). Emissionized engines that meet the California Air Resource Board (C.A.R.B.) or the Environmental Protection Agency (E.P.A.) standards will include additional required engine information on the engine decal (diag. 3). INTERPRETATION OF MODEL NUMBER The first letter designation in a model number indicates basic type of engine. V - Vertical Shaft LAV - Lightweight Aluminum Vertical VM - Vertical Medium Frame TVM - Tecumseh Vertical (Medium Frame) VH - Vertical Heavy Duty (Cast Iron) TVS - Tecumseh Vertical Styled TNT - Toro N’ Tecumseh ECV - Exclusive Craftsman Vertical TVXL - Tecumseh Vertical Extra Life LEV - Low Emissions Vertical H - Horizontal Shaft HS - Horizontal Small Frame HM - Horizontal Medium Frame HHM - Horizontal Heavy Duty (Cast Iron) Medium Frame HH - Horizontal Heavy Duty (Cast Iron) ECH - Exclusive Craftsman Horizontal HSK - Horizontal Snow King HS50 67355H SER 4091D 1 2 COVER BEZEL MODEL AND D.O.M. NUMBER DECAL LOCATED UNDER COVER (IF SO EQUIPPED) PRESS IN AND LIFT HERE TO RELEASE COVER ˙

Tecumseh 3-11HP 4-Cycle L-Head Engines Technician's Handbook

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