TECUMSEH TVT691 V TWIN Engine Full Service & Repair Manual

V-TWIN ENGINE TECUMSEH

i 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 Copyright © 2000 by Tecumseh Products Company All rights reserved. No part of this book may be reproduced or transmitted, in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage and retrieval system, without permission in writing from Tecumseh Products Company Training Department Manager.

ii 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

iii 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 TABLE OF CONTENTS (continued)

iv 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 TABLE OF CONTENTS (continued) Page

1-1 1-1 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) 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) 1-2 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) 1-3 1-4 ENGINE MODEL NUMBER SPECIFICATION NUMBER WARRANTY IDENTIFICATION NUMBER

1-2 The D.O.M. (date of manufacture) indicates the production date of the engine by year and numerical day. (Illust. 1-5) This symbol points out important safety INSTRUCTIONS, WHICH IF NOT FOLLOWED, could endanger the personal safety of YOU and others. Follow all instructions. SHORT BLOCKS New short blocks are identified by a tag marked S.B.V. (Short Block Vertical) located on the engine block. When a short block repair is made, it is vital both the original engine and short block numbers are present on the repaired product for correct future parts identification. (Illust. 1-6) 1-5 1-6 Using model TVT691-600401A D.O.M. 9146 as an example, the interpretation is as follows: TVT691- Is the model number. 60041A Represents the specification number used for properly identifying the parts of the engine. TVT Tecumseh Vertical Twin. 691 Indicates the displacement in cubic centimeters. 9146 Is the D.O.M. (Date of Manufacture) formerly serial number. 9 Is the last digit in the year of manufacture (1999). 146 Indicates the calendar day of that year (146th day or May 26 th of 1999). A,B,C A letter following the D.O.M. number represents the line, shift and plant in which the engine was built. Emissionized engines that meet the California Air Resource Board (C.A.R.B.) or the Environmental Protection Agency (EPA) standards will include additional required engine information on the engine decal. NOTE: To maintain the best possible emission performance, use only Genuine Tecumseh Parts. FUELS Tecumseh Products Company strongly recommends the use of fresh, clean, unleaded regular gasoline in all Tecumseh engines. Unleaded gasoline burns cleaner, extends engine life, and promotes good starting by reducing the build up of combustion chamber deposits. Unleaded regular, unleaded premium or reformulated gasoline containing no more than 10% Ethanol, 15% MTBE or 15% ETBE may be used. Leaded fuel is not available in the United States and should not be used if any of the above options are available. Never use gasoline, fuel conditioners, additives or stabilizers containing methanol, white gas, or fuel blends, which exceed the limits, specified above for Ethanol, MTBE, or ETBE because engine/fuel system damage could result. CAUTION: THE USE OF SOME ANTI-ICING ADDITIVES MAY CREATE A METHANOL FUEL BLEND. DO NOT USE ADDITIVES THAT CONTAIN METHANOL. FUEL CONDITIONERS THAT CONTAIN ISOPROPYL ALCOHOL CAN BE USED IN CORRECT MIXTURE RATIOS. Regardless of which of the approved fuels are used, fuel quality is critical to engine performance. Fuel should not be stored in an engine or container more than 30 days prior to use. Time may be extended with the use of a fuel stabilizer like TECUMSEH, part number 730245. See “STORAGE” instructions in this Manual, Operators Manual, or Bulletin 111. DATE OF MANUFACTURE (D.O.M.) SBV OR SBH IDENTIFICATION NUMBER SHORT BLOCK IDENTIFICATION TAG SERIAL NUMBER SBV- 564A SER 5107

1-3 Change oil and filter after the first two operating hours. Standard oil change intervals are every 50 hours. Oil filter changes are recommended every 100 operating hours. Oil Change Intervals: Change the oil and filter after the first 2 hours of operation. Thereafter oil change intervals are every 50 hours. Oil and oil filter changes are requested every 100 operating hours. Service should be performed more often if operated under extremely dusty or dirty conditions. The oil and filter (if equipped) should be changed yearly if operated less than 100 hours. Oil Check: Check the oil each time the equipment is used or every five-(5) hours of operation. Position the equipment so the engine is level when checking the oil level. CAUTION: A TWIN CYLINDER ENGINE MAY START AND RUN ON ONLY ONE CYLINDER. ALWAYS DISCONNECT BOTH SPARK PLUG WIRES FROM THE SPARK PLUGS AND GROUND TO THE DEDICATED RETAINING POSTS LOCATED ON THE VALVE COVER BOXES BEFORE ATTEMPTING ANY SERVICE OR MAINTENANCE WORK ON THE ENGINE OR EQUIPMENT. ENGINE OIL TECUMSEH FOUR-CYCLE ENGINES REQUIRE THE USE OF CLEAN, HIGH QUALITY DETERGENT OIL. Be sure original container is marked: A.P.I. service “SF” thru “SJ” or “CD”. TECUMSEH RECOMMENDS USING ONE OF THE FOLLOWING FOUR CYCLE OILS THAT ARE SPECIALLY FORMULATED TO TECUMSEH SPECIFICATIONS. DO NOT USE SAE 10W40 OIL. FOR SUMMER (Above 32 0 F) (0 o C) USE SAE 30 OIL. PART 730225 Use SAE 30 oil in high temperature, high load applications. Using multigrade oil may increase oil consumption. FOR WINTER (Below 32 0 F) (0 o C) USE SAE 5W30 OIL. PART 730226 (SAE 10W is an acceptable substitute.) (BELOW 0 0 F (-18 o C) ONLY): SAE 0W30 is an acceptable substitute. Oil Capacity Engine Model oz. ml. TVT691 with Filter 80 2366 TVT691 Oil Only 72 2129 Oil Change Procedure: Locate the oil drain plug in the mounting flange. The drain plug or cap on most units is located above the frame in one of the locations shown. (Illust. 1-7) The oil filter if equipped, can be removed with a commercially available filter wrench. NOTE: An oil change is best performed after the engine is warm. Remove the oil plug or cap and allow the oil to drain into a proper receptacle. Always make sure that drain oil and filter are disposed of properly. Contact your local governing authorities to find a waste oil disposal site. Once the oil is drained, reinstall the drain plug and fill the engine with new oil to the proper capacity. BASIC MAINTENANCE CHART Pre-filter (Dry Poly) Clean every 25 hours Air filter (Paper Element) Replace every 100 hours of operation Oil change Every 50 hours or annually Oil filter Every 100 hours or annually Spark plug replacement Every 100 hours or annually Clean cooling fins Every 200 hours or annually Fuel Filter (Replace) Every 100 hours or annually 1-7 STANDARD OIL DRAIN PLUG LOCATION ALTERNATE LOCATION

1-4 1-8 BASIC TUNE-UP PROCEDURE: NOTE: Today’s fuels can cause many problems in an engines performance due to the fuel quality and short shelf life (as little as 30 days). Always check fuel as a primary cause of poor engine performance before performing any other service. The following is a minor tune-up procedure. When this procedure is completed, the engine should operate properly. Further repairs may be necessary if the engine’s performance remains poor. CAUTION: REMOVE THE SPARK PLUG WIRES AND ATTACH TO THE DEDICATED RETAINING POSTS BEFORE DOING ANY SERVICE WORK ON THE ENGINE. 1. Service or replace the air cleaner. See Chapter 2 under “Service”. 2. Inspect the level and condition of the oil, change or add oil as required. 3. Remove the blower housing and clean all dirt, grass or debris from the intake screen, Cylinder head, cooling fins, carburetor, governor levers and linkage. 4. Check that the fuel filter, fuel tank, and fuel line are clean. We recommend replacing the fuel filter every 100 hours or annually. 5. Replace the spark plugs every 100 hours or annually, consult the parts breakdown for the correct spark plug to be used. Set the spark plug gap (.030") (.762 mm) and install the plug, being careful not to cross thread. Tighten the spark plug to 21 foot pounds (28 Nm) of torque. If a torque wrench is not available, turn the spark plug in as far as possible by hand, then use a spark plug wrench to turn the plug 1/2 turn further. If installing a used plug, only 1/8 to 1/4 turn after seat is needed. Note: The correct plug reach must be used see (Illust. 1-8). 6. Make sure all ignition wires are free of abrasions or breaks and are properly routed so they will not rub on the flywheel. 7. Completely clean the cooling fins, intake screen and linkages of all dirt and debris. Reinstall the blower housing, fuel tank, fuel line, and air cleaner assembly if removed. Be careful not to pinch any of the wires upon re-assembly. 8. Make sure all remote cables are correctly routed and adjusted for proper operation. See Chapter 4, under “Speed Controls and Linkage”. 9. Reinstall the spark plug wires, add fuel and oil as necessary, start the engine. STORAGE (IF THE ENGINE IS TO BE UNUSED FOR 30 DAYS OR MORE) CAUTION: NEVER STORE THE ENGINE WITH FUEL IN THE TANK INDOORS OR IN ENCLOSED, POORLY VENTILATED AREAS, WHERE FUEL FUMES MAY REACH AN OPEN FLAME, SPARK OR PILOT LIGHT AS ON A FURNACE, WATER HEATER, CLOTHES DRYER OR OTHER GAS APPLIANCE. Gasoline can become stale in less than 30 days and form deposits that can impede proper fuel flow and engine operation. To prevent deposits from forming, all gasoline must be removed from the fuel tank and the carburetor. An acceptable alternative to removing all gasoline, is by adding Tecumseh fuel stabilizer, part number 730245, to the gasoline. Fuel stabilizer is added to the fuel tank or storage container. Always follow the mix ratio found on the stabilizer container. Run the engine at least 10 minutes after adding the fuel stabilizer to allow it to reach the carburetor. (Illust. 1-9) 1-9 STANDARD PLUG OHV

2-1 2-1 CHAPTER 2. AIR CLEANERS GENERAL INFORMATION The air cleaner is the device used to eliminate dust and dirt from the air supply. Filtered air is necessary to assure that abrasive particles are removed before entering the combustion chamber. Dirt allowed into the engine will quickly wear the internal components and shorten engine life. The TVT series engine uses a paper-type air filter system and also has a dry foam pre-filter. Extremely dirty conditions require more frequent pre-filter cleaning or paper element replacement. OPERATION The air filter cover secures and seals the paper filter element in place. The cover also prevents large particles from entering the filter body and completes the Kleen- Aire ® circuit. The air is first filtered through the flywheel and blower housing then enters the air filter cover. It travels through the pre-filter then the paper filter element. Pre-filters typically extend the paper filter life. (Illust. 2-1) COMPONENTS The cover holds the poly pre-cleaner and clamps the paper filter in place, creating a dirt tight seal. The cover also prevents large debris from entering the filter body. The pre-cleaner is made of a polyurethane foam and designed to pre-filter the air prior to it passing through the paper filter. This added stage, assures the operator of maximum air filtering and extends paper filter life. The paper filter element is the main filter to stop impurities from entering the engine. This dry-type element is pleated paper for increased surface area maximizing its life. The filter has rubberized edges to assure sealing. (Illust. 2-2) TROUBLESHOOTING AND TESTING If the engine’s performance is unsatisfactory (runs unevenly, starts smoking abnormally or loses power), the first engine component(s) to be checked are the air filter(s). A dirt restricted or oil soaked filter will cause noticeable performance problems. Polyurethane pre-filter can be cleaned following the service procedure listed under “Service” in this chapter. A paper-type air filter can only be replaced NEVER attempt to clean a paper filter. The paper-type filter must not have any oil film or residue present. Should the paper have a brown tint it may have been damaged by an excessively oiled pre-filter or crankcase breather problems. Follow the procedure listed in the “Service” section of this chapter for filter replacement or cleaning. 2-2

TECUMSEH TVT691 V TWIN Engine Full Service & Repair Manual

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