Tecumseh V-Twin Engine Repair Manual

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TECUMSEH

V-TWIN

ENGINE

TABLE OF CONTENTS

CHAPTER 1.	GENERAL INFORMATION
CHAPTER 2.	AIR CLEANERS
CHAPTER 3.	CARBURETORS AND FUEL SYSTEMS
CHAPTER 4.	GOVERNORS AND LINKAGE
CHAPTER 5.	ELECTRICAL SYSTEMS
CHAPTER 6.	IGNITION
CHAPTER 7.	INTERNAL ENGINE AND DISASSEMBLY
CHAPTER 8.	ENGINE ASSEMBLY
CHAPTER 9.	TROUBLESHOOTING AND TESTING
CHAPTER 10.	ENGINE SPECIFICATIONS

i

TABLE OF CONTENTS

(by subject)

GENERAL INFORMATION

	Page
Engine Identification	1-1
Interpretation of Engine Identification	1-1
Short Blocks	1-2
Fuels	1-2
Engine Oil	1-3
Basic Tune-Up Procedure	1-4
Storage	1-4

AIR CLEANERS

General Information	2-1
Operation	2-1
Components	2-1
Troubleshooting and Testing	2-1
Service	2-2

CARBURETORS AND FUEL SYSTEMS

General Information	3-1
Float Style Carburetors	3-1
Operational Circuits Series 7 Carburetor	3-1
Testing	3-3
Carburetor Disassembly Procedure	3-5
Inspection	3-7
Carburetor Re-Assembly	3-7
Throttle Shaft and Plate	3-7
Choke Shaft and Plate	3-8
Fuel Bowl Assembly	3-8
Impulse Fuel Pumps	3-9
Impulse Fuel Pump Service	3-10

GOVERNORS AND LINKAGE

General Information	4-1
Operation	4-1
Troubleshooting	4-1
Engine Speed Adjustments	4-1
Engine Overspeed	4-2
Engine Surging	4-2
Governor Service
Static Adjustment - Governor	4-2
Governor Gear and Shaft Service	4-3
Governor Shaft Replacement	4-3

ii

TABLE OF CONTENTS (continued)

	Page
Speed Controls and Linkage	4-3
Synchronizing the Carburetors	4-4
Choke Synchronization	4-5

ELECTRICAL SYSTEMS

General Information	5-1
Operation	5-1
Converting Alternating Current to Direct Current	5-2
Components
Battery	5-2
Wiring	5-2
Condition	5-2
Wire Gauge	5-2
Electrical Terms	5-3
Basic Checks	5-3
Charging Circuit	5-4
3 Amp D.C. 5 Amp A.C. Alternator	5-4
Diode Replacement	5-4
Checking the System	5-5
16 Amp Alternator System with External Regulator	5-5
Troubleshooting Electrical Charging Circuit Flow Chart	5-6
Voltage Regulators	5-7
Fuel Shut-Down Solenoids	5-7
Low Oil Pressure Sensor Testing	5-7
Starting Circuit	5-8
Testing Procedure Starting Circuit	5-8
Troubleshooting Electrical Starter Circuit Flow Chart	5-9
Electric Starter Service	5-10
12 Volt Electric Starter	5-10
Inspection and Repair	5-11
Brush Holder	5-12
Brush Replacement	5-12

IGNITION

General Information	6-1
Operation
Solid State Ignition System (CDI)	6-1
Components	6-1
Testing Procedure	6-2
Service
Spark Plug Service	6-3
Conditions Causing Frequent Spark Plug Fouling	6-3
Ignition Timing	6-3
Service Tips	6-4

iii

TABLE OF CONTENTS (continued)

	Page
INTERNAL ENGINE AND DISASSEMBLY
General Information	7-1
Lubrication Systems	7-1
Disassembly Procedure	7-1
Disassembly of Cylinder Heads	7-4
Valves	7-5
Valve Guides	7-5
Valve Springs	7-6
Push Rods	7-6
Valve Seats	7-6
Internal Engine Component Inspection
Cylinders	7-7
Pistons	7-8
Rings	7-9
Connecting Rods	7-10
Crankshafts and Camshafts	7-11
Mechanical Compression Release	7-12
Valve Lifters	7-13
Crankcase Breather	7-13
Cylinder Cover	7-13
ENGINE ASSEMBLY
Engine Assembly	8-1
TROUBLESHOOTING AND TESTING
Engine Knocks	9-1
Engine Overheats	9-1
Surges or Runs Unevenly	9-1
Engine Misfires	9-1
Engine Vibrates Excessively	9-2
Breather Passing Oil	9-2
Excessive Oil Consumption	9-2
Lack Power	9-2
ENGINE SPECIFICATIONS
TVT691 Engine Specifications	10-1
Torque Specifications	10-3
Service Tool List	10-4

iv

CHAPTER 1. GENERAL INFORMATION

ENGINE IDENTIFICATION

Tecumseh engine model, specification, and date of manufacture (D.O.M.) are located on decals attached to the blower housing of the engine. The engine identification decal also provides the applicable warranty code, oil and fuel recommendations, EPA (Environmental Protection Agency) and C.A.R.B. (California Air Resource Board) Emission Compliance Information. (Illust. 1-1)

The group of numbers following the model number is the specification number. The last three numbers indicate a variation to the basic engine specification. (Illust. 1-3)

SPECIFICATION

NUMBER

1-1

INTERPRETATION OF ENGINE

IDENTIFICATION

The letter designations (TVT) in a model number indicate the basic type of engine.

The number designations following the letters (691) indicate the basic engine model displacement in CC’s (cubic centimeters). (Illust. 1-2)

ENGINE

MODEL

NUMBER

1-2

1-3

The letter in parenthesis on the engine information decal is the warranty code identification number. This letter designates the length of time the engine is under warranty. A cross-reference may be found in the service warranty policy of the master repair manual or the engine operator’s manual. (Illust. 1-4)

WARRANTY

IDENTIFICATION

NUMBER

1-4

1-1