Tecumseh TM SERIES, TC SERIES, TC300-3133C(B)5114G, TC300 SERIES, TC200 SERIES Technician's Handbook

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TECUMSEH

T E C H N I C I A N ‘ S H A N D B O O K

TC/TM SERIES 2-Cycle Engines

ENGINES TRANSMISSIONS

MPORTANT NOTICE!

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covers repairs and adjustments not covered within the who have a general understanding of internal combustion

nes, adequate training, experience and who practice proper

eng tool usage. pract

perator’s Manual, and it is intended for individuals

ervice procedures should be clearly understood and

en servicing Tecumseh Engines.

afety Deﬁ nition

tatements in this manual preceded by the following words and

graphics are o

special signiﬁ cance:

WARNING

WARNING indicates a potentially hazardous situation which if not avoided, could result in death or serious injury.

Tecumseh Contact Informatio

Contact your nearest Authorized Tecumseh Servicing Dealer if:

• You are unable to vered in this han

• You have vered in this han

• You would like to order service tools.

• You would like to re

copies of this handbook.

ou may ﬁ nd your Authorized Tecumseh Servicing

r call Tecumseh Power Company at 1-800-558-5402 r 262-377-2700 if you are located outside the U.S. or

anada.

uestions about service procedures

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erform service procedures

uest additional printed

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Refers to important information and is placed in italic type.

It is recommended that you take special notice o discussed on pages 1 and 2 and wear the appropriate safety equipment.

all items

otice Regarding Emission

OTE Engines which are certiﬁ ed to comply with California and U.S. EPA emission regulations for SORE (Small Off Road Equipment), are certiﬁ ed to operate on regular unleaded gasoline, and may include the following emission control systems: (EM) Engine

Modiﬁ cation and

TWC) Three-way Catalyst (if so equipped).

ecumseh Power Compan

ll Rights Reserved

CONTENTS

CHAPTER 1 GENERAL INFORMATION...............................................................................1

GENERAL SAFETY PRECAUTIONS ..................................................................................................... 1

ENGINE IDENTIFICATION ..................................................................................................................... 3

OIL REQUIREMENTS............................................................................................................................. 5

FUEL REQUIREMENTS ......................................................................................................................... 6

TUNE-UP PROCEDURE ........................................................................................................................ 7

STORAGE............................................................................................................................................... 8

CHAPTER 2 AIR CLEANERS................................................................................................9

GENERAL INFORMATION ..................................................................................................................... 9

OPERATION ........................................................................................................................................... 9

TROUBLESHOOTING ............................................................................................................................ 9

SERVICE................................................................................................................................................. 9

PAPER FILTER REMOVAL AND REPLACEMENT.............................................................................. 10

POLYURETHANE FILTER REMOVAL AND SERVICE........................................................................ 10

CHAPTER 3 CARBURETORS AND FUEL SYSTEMS .......................................................11

GENERAL INFORMATION ................................................................................................................... 11

OPERATION ......................................................................................................................................... 11

FUEL PRIMERS.................................................................................................................................... 12

COMPONENTS..................................................................................................................................... 13

ENGINE TROUBLESHOOTING ........................................................................................................... 16

TROUBLESHOOTING CARBURETION—TC/TM SERIES .................................................................. 17

TESTING............................................................................................................................................... 19

SERVICE............................................................................................................................................... 19

CARBURETOR PRE-SET AND ADJUSTMENT ................................................................................... 19

CARBURETOR DISASSEMBLY .......................................................................................................... 20

CARBURETOR INSPECTION .............................................................................................................. 20

CARBURETOR ASSEMBLY................................................................................................................. 21

FUEL TANK SERVICE .......................................................................................................................... 24

CHAPTER 4 GOVERNORS AND LINKAGE .......................................................................25

GENERAL INFORMATION ................................................................................................................... 25

OPERATION ......................................................................................................................................... 25

COMPONENTS..................................................................................................................................... 25

TROUBLESHOOTING .......................................................................................................................... 26

ENGINE OVERSPEEDING ................................................................................................................... 26

ENGINE SURGING ............................................................................................................................... 26

SERVICE............................................................................................................................................... 26

GOVERNOR ADJUSTMENT ................................................................................................................ 26

CHAPTER 5 REWIND STARTERS......................................................................................28

GENERAL INFORMATION ................................................................................................................... 28

OPERATION ......................................................................................................................................... 28

TC TYPE I ............................................................................................................................................. 28

TC TYPE II/TM ...................................................................................................................................... 28

COMPONENTS..................................................................................................................................... 28

SERVICE............................................................................................................................................... 28

DISASSEMBLY PROCEDURE ............................................................................................................. 28

ASSEMBLY PROCEDURE ................................................................................................................... 29

©Tecumseh Power Company

2005

CHAPTER 6 IGNITION ........................................................................................................30

GENERAL INFORMATION ................................................................................................................... 30

OPERATION ......................................................................................................................................... 30

COMPONENTS..................................................................................................................................... 30

IGNITION TROUBLESHOOTING ......................................................................................................... 31

TESTING............................................................................................................................................... 32

SERVICE............................................................................................................................................... 32

AIR GAP SETTING ............................................................................................................................... 32

SPARK PLUG SERVICE....................................................................................................................... 32

CHAPTER 7 INTERNAL ENGINE AND CYLINDER ...........................................................33

GENERAL INFORMATION ................................................................................................................... 33

OPERATION ......................................................................................................................................... 33

MANUAL COMPRESSION RELEASE.................................................................................................. 33

COMPONENTS..................................................................................................................................... 34

TROUBLESHOOTING ..................................................................................................................... 35-36

TESTING............................................................................................................................................... 37

ENGINE KNOCKS ................................................................................................................................ 37

ENGINE OVERHEATS ......................................................................................................................... 37

SURGES OR RUNS UNEVENLY .........................................................................................................37

ENGINE MISFIRES............................................................................................................................... 37

ENGINE VIBRATES EXCESSIVELY .................................................................................................... 38

LACKS POWER OR WILL NOT START............................................................................................... 38

SERVICE............................................................................................................................................... 38

GENERAL INFORMATION ................................................................................................................... 38

DISASSEMBLY PROCEDURE—TC TYPE 1 AND TC TYPE II ...................................................... 38-40

BEARING AND SEAL SERVICE—TC TYPE I AND TC TYPE II .......................................................... 40

ASSEMBLY—TC TYPE I AND TC TYPE II ..................................................................................... 41-43

DISASSEMBLY—TM ....................................................................................................................... 43-44

BEARING AND SEAL SERVICE—TM .................................................................................................. 44

ASSEMBLY—TM ............................................................................................................................. 45-47

CHAPTER 8 ENGINE SPECIFICATION AND SEARS CRAFTSMAN

CROSS-REFERENCE ...............................................................................................48

TORQUE SPECIFICATIONS ................................................................................................................ 48

ENGINE SPECIFICATIONS.................................................................................................................. 49

SEARS CRAFTSMAN CROSS REFERENCE ...................................................................................... 50

CHAPTER 9 EDUCATIONAL MATERIALS AND TOOLS .............................................51-54

CHAPTER 1 GENERAL INFORMATION

I. General Safety Precautions

WARNING

Read the original equipment manufacturer’s manual(s) and this handbook thoroughly before servicing Tecumseh engines. Always follow recommended service procedures. Such procedures affect the safe operation of the equipment and the safety of you and/or the operator. Failure to follow the instructions and warnings may result in serious injury or death. Call Tecumseh Power Company at 1-800-558-5402 or visit www.TecumsehPower.com if you have any questions.

A. Use Personal Protective Equipment

To avoid injury, wear protective equipment including appropriate clothing, eyewear, safety shoes and ear plugs when servicing Tecumseh products.

B. Stay Away from Rotat-

ing Parts

Rotating parts can cause severe injury or death. Use special care when making service adjustments with covers or guards removed. Keep tools, hands, feet, hair, jewelry, and clothing away from all moving parts. Replace covers and guards before operating equipment.

C. Stay Away from Hot Sur-

faces

Parts of equipment being serviced become extremely hot during operation and remain hot after the equipment has stopped. To avoid severe burns, stay away from hot surfaces or allow the unit to cool prior to service.

D. Avoid Accidental Equipment Movement

To prevent accidental movement of equipment, always set the parking brake. For gear-driven products that do not have a parking brake, leave equipment in gear and chock the wheels. Refer to original equipment operator manuals for additional information. Pulley bosses that hold the rewind spring inside the keeper and spring housing may not be secured and can be easily loosened. Use special care when handling this housing. Failure to do so could cause spring to “fly out” which could result in minor or moderate injury.

Always discard gaskets, O-rings and seals after removal. Use only new gaskets, O-rings and seals for assembly. Failure to do so could result in leakage from engine areas that use these parts.

E. Always Provide Adequate Ventilation

To avoid serious injury or death, always ensure that you are working in a properly ventilated facility. Special precautions are required to avoid carbon monoxide poisoning. All engine exhaust contains carbon monoxide, a deadly gas. Breathing carbon monoxide can cause headaches, dizziness, drowsiness, nausea, confusion and eventually death. Carbon monoxide is a colorless, odorless, tasteless gas which may be present even if you do not see or smell any engine exhaust. Deadly levels of carbon monoxide can collect rapidly and you can quickly be overcome and unable to save yourself. Also, deadly levels of carbon monoxide can linger for hours or days in enclosed or poorly-ventilated areas. If you experience any symptoms of carbon monoxide poisoning, leave the area immediately, get fresh air, and SEEK MEDICAL TREATMENT. To prevent serious injury or death from carbon monoxide:

• ALWAYS direct engine exhaust outdoors.

• NEVER run engine outdoors where engine exhaust can be drawn into a building through openings such as windows and doors.

F. Use Proper Methods When Cleaning

To reduce the risk of serious injury or death from fires and/or explosions, NEVER use flammable solvents (e.g., gasoline) to clean serviceable parts. Use a water-based, non-flammable solvent such as Tecumseh Degreaser Cleaner.

G. Compressed Air Precautions

Never use compressed air to clean debris from yourself or your clothing. When using compressed air to clean or dry serviceable parts:

• Wear appropriate eye protection.

• Use only approved air blow nozzles.

• Air pressure must not exceed 30psi (206kPa).

• Shield yourself and bystanders from flying debris.

H. Inspect and Adjust Brake(s)

Always inspect and adjust flywheel brake components whenever servicing equipment that has a Tecumseh engine. Refer to this Technician’s Handbook and bulletins for proper brake adjustment.

I. Operate Equipment Safely

Operation of equipment presented for service can be hazardous. To avoid serious injury or death, DO NOT operate equipment, until:

• all relevant inspection procedures presented in this handbook are performed and

• technician is satisfied equipment can be operated safely.

• Starter pulley springs hold the starter rope and control tension by winding the rope around the pulley. Use caution when pulling and releasing the rope to and from the starter housing. Failure to do so could cause the rope to unexpectedly jerk back which could result in minor or moderate injury.

J. Avoid Gasoline Fires

Gasoline (fuel) vapors are highly flammable and can explode. Fuel vapors can spread and be ignited by a spark or flame many feet away from engine. To prevent injury or death from fuel fires, follow these instructions:

• NEVER store engine with fuel in fuel tank inside a building with potential sources of ignition such as hot water and space heaters, clothes dryers, electric motors, etc.

• NEVER remove fuel cap or add fuel when engine is running.

• NEVER start or operate the engine with the fuel fill cap removed.

• Allow engine to cool before refueling.

• NEVER fill fuel tank indoors. Fill fuel tank outdoors in a well-ventilated area.

• DO NOT smoke while refueling tank.

• DO NOT pour fuel from engine or siphon fuel by mouth.

K. Avoid Accidental Starts

To prevent accidental starting when working on equipment always:

• Disconnect spark plug wire and keep it away from spark plug.

• Keep the disconnected spark plug wire securely away from metal parts where arcing could occur.

• Attach the spark plug wire to the grounding post, if provided.

• Turn off all engine switches.

ENGINE IDENTIFICATION

Engine Model Families

This Tecumseh Technician’s Handbook covers the following engine model types:

• TC200 - Two Cycle Engine Type I - 2.0 cubic inch displacement.

• TC300 - Two Cycle Engine Type II - 3.0 cubic inch displacement.

• TM049XA- Two Cycle Engine Multi Position - 49cc displacement.

The letter designations in a model number indicate the basic type of engine. See diag.1-4.

The number designations following the letters indicate the basic engine model.

The number following the model number is the specification number. The last three numbers of the specification number indicate a variation to the basic engine specification.

The serial number or D.O.M. indicates the production date of the engine.

TC engine identification numbers are stamped into the blower housing or blower housing base near the spark plug, or a decal is permanently attached to the side of the blower housing. See diag. 1-1.

Identification Decal

TC TYPE I ENGINE

TC TYPE II and TM ENGINES

1-1

The engine identification decal will include the model number, engine type, warranty code, and date of manufacture. See diag. 1-2 and 1-3.

The model number designation following TC (Tecumseh Compact) indicate the cubic inch displacement of the engine. TC300 indicates a 3.0 cubic inch displacement.

The number (3133C) following the model number is the specification number. The last two numbers and letter character (33C) indicate a variation to the basic engine specification.

The warranty code letter (B) indicates the length of warranty that is supplied by Tecumseh.

The DOM (Date of Manufacture) or Serial Number indicate the date the engine was produced. The first digit (5) is the year in the decade (1995). The next three digits (114) indicate the build date (114th day of the year or April 24). The letter designation indicates the line or shift on which the engine was built at the factory.

Short blocks are identified by a tag marked SBH (Short Block Horizontal) or SBV (Short Block Vertical). See diag. 1-5.

I. TC200 Models

A sample TC200 decal is pictured for reference. See diag. 1-2. Using model TC200-2015B 2354D as an example, interpretation is as follows: See Table 1-1.

12 3

2015BTC200 2354D

1. Engine Model Number

2. Specification Number

3. D.O.M. (Date of Manufacture)

Sample TC200 Decal

1-2

Table 1-1. TC200 Engine Model Code Designations

Code Model Number

T Indicates Tecumseh Engine Manufac-

turer.

C Indicates compact model.

200 Indicates 2.0 cubic inch displacement.

Code Specification Number

2015B Indicates number used for identifying the

parts of the engine.

Code Serial/D.O.M. Designation

2 Is the last digit in the year of manufacture

(1992).

354 Indicates the calendar day of that year

(354th day or December 20).

D Indicates the plant line and shift on which

the engine was built at the factory.

II. TC300 Models

A sample TC300 decal is pictured for reference. See diag. 1-3. Using model TC300-3133C(B)5114G as an example, interpretation is as follows: See Table 1-2.

12 3 4

3133C (B)TC300 5114G

1. Engine Model Number

2. Specification Number

3. Warranty Category

4. D.O.M. (Date of Manufacture)

Sample TC300 Decal

1-3

Table 1-2. TC300 Engine Model Code Designations

Code Model Number

T Indicates Tecumseh Engine Manufac-

turer.

C Indicates compact model.

300 Indicates 3.0 cubic inch displacement.

Code Specification Number

3133C Indicates number used for identifying the

parts of the engine.

Code Warranty Code

B Indicates Warranty Information. See

current Operator’s Manual for information.

Code Serial/D.O.M. Designation

5 Is the last digit in the year of manufacture

(1995).

114 Indicates the calendar day of that year

(114th day or April 24).

G Indicates the plant line and shift on which

the engine was built at the factory.

III. TM Models

A sample TM decal is pictured for reference. See diag. 1-4. Using model TM049XA 3617B A 4056CA as an example, interpretation is as follows: See Table 1-3.

12 3 4

3617B (A)TM049XA 4056CA

1. Engine Model Number

2. Specification Number

3. Warranty Category

4. D.O.M. (Date of Manufacture)

Sample TM Decal

1-4

Table 1-3. TM Engine Model Code Designations

Code Model Number

T Indicates two cycle model.

M Indicates multi position model.

049 Indicates Displacement-49cc

XIs 49 State/Global Emissions Compliant.

A Indicates standard Model.

Code Specification Number

3617B Indicates specification number used for

identifying the parts of the engine.

Code Warranty Code

A Indicates Warranty Information. See cur-

rent Operator’s Manual for details.

Code Serial/D.O.M. Designation

4056CA Is the serial number or D.O.M. (Date of

Manufacture).

4 Is the last digit in the year of manufacture

(2004).

056 Indicates the calendar day of that year

(56th day or February 25).

C Indicates the plant line and shift on which

the engine was built at the factory.

A Indicates the location of where the engine

was built at the factory.

Short Blocks

New short blocks are identified by a tag marked SBH (Short Block Horizontal) or SBV (Short Block Vertical). Original model identification numbers of an engine should always be transferred to a new short block for correct parts identification. See diag. 1-5.

SBV OR SBH Identification Number

SBV- 564A SER 5107

Serial Number

1-5

Short Block Identification Tag

OIL REQUIREMENTS

Tecumseh recommends using two-cycle oil part # 730227C, which is a synthetic blend that ensures cylinder wall lubrication, mixes easy, and does not separate. Two cycle oil part # 730227C is specially formulated for use in air or water cooled two cycle engines and contains an added fuel stabilizer.

Tecumseh two cycle engines require the use of a NMMA TC-W3 or TC-WII certified oil.

The proper fuel mixture ratio of oil to gasoline for specific engines will be found in the Operator’s Manual and on the decal attached to the blower housing or fuel tank of the engine.

FUEL REQUIREMENTS

Tecumseh Power 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. Leaded gasoline, gasohol containing no more than 10% ethanol, premium gasoline, or unleaded gasoline containing no more than 15% MTBE (Methyl Tertiary Butyl Ether), 15% ETBE (Ethyl Tertiary Butyl Ether) or 10% ethanol, can be used if unleaded regular gasoline is not available.

Reformulated gasoline that is now required in several areas of the United States is also acceptable.

NEVER USE: gasoline, fuel conditioners, additives or stabilizers containing methanol. The use of white gas, gasohol containing more than 10% ethanol, unleaded regular gasoline containing more than 15% MTBE (Methyl Tertiary Butyl Ether), 15% ETBE (Ethyl Tertiary Butyl Ether) or 10% ethanol is not recommended as engine/fuel system damage could result.

See “STORAGE” instructions in Technician’s Manual, Operator’s Manual, or Bulletin 111.

Tecumseh two-cycle oil part # 730227C contains a fuel stabilizer for year round fuel stability in and out of season. If oil other than Tecumseh two cycle is used, use Tecumseh's fuel stabilizer part # 730245.

MIXING FUEL AND OIL

WARNING

potential sources of ignition such as hot water and space heaters, clothes dryers, electric motors, etc.

DO NOT mix fuel and oil directly in fuel tank.

Use of NMMA, TC-WII or TC-W3, JASO FB or JASO FC classified oil is recommended.

1. Be sure container is outdoors and in a well-ventilated area.

2. Fill approved clean red GASOLINE container with 1/4 of recommended fuel amount. See Table 1-4 and Table 1-5.

3. Add required amount of recommended oil to fuel. See Table 1-4.

4. Screw cap onto container.

5. Shake container vigorously.

6. Unscrew cap from container.

7. Fill container with remainder of recommended fuel. See Table 1-4 and Table 1-5.

8. Wipe away any spilled fuel or oil.

NEVER store engine with fuel in fuel tank inside a building with

Table 1-4. Fuel Mix Chart — Mixture Ratio 24:1

U.S. S.I. Metric

Gas Oil Petrol Oil

1 Gal. 5 oz. 4 Liters 167 ml

2 Gal. 11 oz. 8 Liters 333 ml

5 Gal. 27 oz. 20 Liters 833 ml

Table 1-5. Recommended Fuel

Fuel Component Percentage

Ethanol 10%

Grain Alcohol (“Gasohol”) 10%

MTBE (Methyl Tertiary Butyl Ether) 15%

ETBE (Ethyl Tertiary Butyl Ether) 15%

FUEL ADDITIVES

Only fuel additives such as Tecumseh's fuel stabilizer part # 730245A or liquid varieties can be used when mixed properly. For winter applications, Isopropyl alcohol fuel dryers may be used in the fuel system but must be mixed at the proper ratio recommended by the manufacturer. NEVER USE METHANOL BASED DRYERS.

Gasoline and oil containers must be clean, covered, and rust-free. Old gas or fuel contamination can restrict or block fuel filters, and small fuel ports and passages in the carburetor. If the engine is to be unused for 30 days or more see "Storage" for fuel system instructions.

TUNE-UP PROCEDURE

The following is a minor tune-up procedure. If the engine does not perform properly after the tune-up is completed, consult the "Troubleshooting Engine Operation Chart" found in Chapter 7. Repair procedures are listed in each chapter.

CAUTION

1. Service or replace the air cleaner as necessary. Use the applicable procedure found in Chapter 2 under "Service".

2. Remove the fuel from the fuel tank by running the engine until stopping or draining into an approved fuel container.

3. Remove the fuel tank and blower housing to clean all debris from the air intake screen, cylinder cooling fins, governor and carburetor linkage.

4. Replace the blower housing and check all remote linkage for proper adjustment and operation.

5. Check to see that the engine is properly secured to the equipment. On rotary lawnmowers, balance the blade and check the blade hub and crankshaft key for wear. Replace as necessary. Torque the bolts to the correct specification.

6. Replace the spark plug with the correct replacement by using the Master Parts Manual. Set the spark plug gap at .030" (.762 mm) and install it in the engine. Tighten the spark plug to 230 inch pounds (2.6 Nm) of torque. If a torque wrench isn't available, screw the spark plug in as far as possible by hand. Use a spark plug socket or wrench to turn the spark plug 1/8 to 1/4 turn further if using the old spark plug, or 1/2 turn further if a new spark plug is used. Reinstall the spark plug wire.

7. Fill the fuel tank with the proper fuel/oil mix.

8. Start the engine and allow it run 3 - 5 minutes to reach operating temperature. Adjust the carburetor if necessary (see Chapter 3 under "Service" for the final idle mixture adjustment procedure) and set the engine R.P.M.(s) according to the specification number found on microfiche card # 30 or computer parts lookup system.

Remove the spark plug wire before doing any service work on the engine.

STORAGE (IF THE ENGINE IS TO BE UNUSED FOR 30 DAYS OR MORE.)

WARNING

Gasoline can become unstable 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 adding a fuel stabilizer to the gasoline such as Tecumseh part # 730245A. A fuel stabilizer is added to the fuel tank or storage container. Always follow the mix ratio and mixing procedure found on the stabilizer container. Run the engine at least 10 minutes after adding the stabilizer to allow it to reach the carburetor.

Draining The Fuel System

1. Remove all gasoline from the fuel tank by running the engine until the engine stops, or by draining the fuel tank by removing the fuel line at the carburetor. Be careful not to damage the fuel line or the carburetor fitting. Drain the fuel into an approved container outdoors, and away from any open flame or combustive source. Be sure the engine is cool.

WARNING

2. If "Gasohol" has been used, complete the above procedure and then put 2 ounces (60 ml) of the recommended fuel / oil mixture using regular unleaded gasoline into the fuel tank. Run the engine until it stops due to a lack of fuel. If "Gasohol" is allowed to remain in the fuel system during storage, the alcohol content may cause gaskets and seals to deteriorate.

Oil Cylinder Bore

1. Remove the spark plug wire from the spark plug. Pull the starter handle slowly until resistance is felt due to compression pressure, then stop. Slowly release starter tension to prevent the engine from reversing due to compression pressure.

Never store the engine with fuel in the fuel tank inside a building with potential sources of ignition such as hot water or spacer heaters, clothes dryers, electric motors, etc.

To avoid death or serious injury, DO NOT pour fuel from engine or siphon fuel by mouth.

2. Remove the spark plug, squirt 1/2 ounce (15 ml.) of clean 2-cycle engine oil into the spark plug hole.

3. Cover the spark plug hole with a shop towel and crank the engine over, slowly, several times.

4. Replace the spark plug and tighten (see step # 6 under Tune-Up Procedure for proper spark plug torque). Pull the starter handle as performed in step # 1. The piston position blocks the cylinder ports, preventing atmospheric air from entering and oil from leaving the cylinder bore during storage.

5. Replace the spark plug wire on the spark plug.

CHAPTER 2 AIR CLEANERS

GENERAL INFORMATION

The air cleaner is designed to eliminate dust and dirt from the air supply. Most models of 2-cycle and 4-cycle engines use an air cleaner except engines that run in clean environments like snow throwers or ice augers. On these applications, a filter is not necessary and could collect snow or moisture and prevent proper engine operation. On most applications, filtered air is necessary to assure abrasive particles are removed before entering the combustion chamber. Dirt allowed into the engine will quickly wear the internal components and shorten the life of the engine.

Tecumseh engines use either a polyurethane or a paper type air filter system. A polyurethane pre-filter or a flocked screen may be used in conjunction with the main filter. Extremely dirty operating conditions may require frequent filter cleaning or replacement.

OPERATION

The outer cover holds the air filter element(s) and prevents debris from entering the filter box. The air supply is filtered through the pre-filter if equipped, filter element (polyurethane or paper), and a flocked screen if equipped. Pre-filter elements do not extend the recommended air filter service intervals listed under "Service". However; in extremely dirty operating conditions a pre-filter element may increase the run time of the engine before the filter becomes restricted (not to exceed the service recommendations), and service on the filter is necessary.

TROUBLESHOOTING

If the engine's performance is unsatisfactory (needs excessive adjustments, starts smoking abnormally, loses power), the first component to be checked is the air cleaner. A dirt restricted or an oil soaked filter element will cause noticeable performance problems. A polyurethane element may be cleaned following the service procedure listed under "Service" in this chapter. A paper-type air filter should only be replaced. Follow the procedure listed in the service section in this chapter for replacement. Retry the engine after filter replacement or service. If the problem persists after filter service, additional solutions can be found in Chapter 7 under "Troubleshooting".

SERVICE

Cleaning and oiling the polyurethane element (diag. 2-1) is recommended every three (3) months or every 25 operating hours. If the engine is used in extremely dusty or dirty conditions, the filter may require service every three hours or as often as necessary to maintain proper engine performance.

Polyurethane type filters require re-oiling after extended storage due to oil migration out of the filter.

A paper type element (diag. 2-2) should be replaced once a year, every 100 operating hours, or more often if used in extremely dusty conditions. Use only original factory recommended replacement filters.

NOTE

DO NOT attempt to clean or oil paper filters.

Polyurethane Filter

Air Cleaner Screen

2-1

Cover

Air Cleaner

Collar

Clamp

2-2

Paper Filter Removal and Replacement

1. Remove the polyurethane pre-filter (if equipped) from the air filter.

2. Inspect the filter(s) for discoloration or dirt accumulation. (For the polyurethane pre-cleaner service see step # 5 under "Polyurethane Filter Removal and Service"). If either condition is present, replace the paper type filter using the following steps.

3. Loosen the clamp and slide the clamp toward the air filter (diag. 2-3).

4. Slide the air filter and clamp off the carburetor adapter. Discard the old filter and keep the clamp.

Hose Clamp

Poly Pre-Filter

Air Cleaner

Clamp

Carburetor Adapter

5. Apply a thin layer of silicon sealant to the outside of the air cleaner adapter.

6. Install the clamp on the new air filter, slide the filter assembly onto the carburetor adapter as far as it will go.

7. Slide the clamp as close to the carburetor as possible. Tighten the clamp securely.

Polyurethane Filter Removal and Service

Kleen Aire® Air Cleaner, TC Type II or TM

1. Remove the cover by pulling outward on the tab (diag. 2-4). On the TC Type II/TM style engine, loosen the two screws (diag. 2-5).

2. Remove screen A (if equipped), foam filter and screen B from the air cleaner body (diag. 2-4). On TC Type II/TM engines, remove the flocked screen and the foam filter (diag. 2-5).

3. Inspect the flocked screen and foam filter for discoloration or dirt accumulation. If either condition is present, service the element or screen using the following steps.

4. The flocked screen pre-filter may be cleaned by blowing compressed air through the screen from the back side. Replace the screen if this procedure does not fully remove the accumulated particles.

Screen A

Polyurethane Filter

TC TYPE II/TM

Carburetor

2-3

Screen B

2-4

Lock Nut

Washer

Fuel Tank

5. Wash the polyurethane filter or polyurethane pre-filter (used with paper air filters) in a detergent water solution and squeeze (don't twist) until all dirt is removed.

6. Rinse the polyurethane filter or polyurethane pre-filter thoroughly in clean water. Wrap the filter in a clean cloth and squeeze (don't twist) until completely dry.

7. Reassemble the filter assemblies per the illustrations.

Air Cleaner Housing

Poly Air-Cleaner

Flocked Screen

Air Cleaner Cover

Cover Screw

2-5

CHAPTER 3 CARBURETORS AND FUEL SYSTEMS

GENERAL INFORMATION

TC/TM engines almost exclusively use diaphragm-type carburetors to be able to run effectively at any operating angle. The diaphragm carburetors are produced by Tecumseh, Walbro and Tillotson for Tecumseh. The carburetors use an internal diaphragm fuel pump to supply the fuel to the carburetor fuel metering chamber. The metering diaphragm has one side exposed to intake manifold pressure and one side exposed to atmospheric pressure. This diaphragm provides the same basic function (maintaining the proper fuel level in the carburetor) as the float.

A limited number of TC engines were produced as outboards using a Tecumseh Series II float style carburetor. Consult the Two Cycle Technician's Handbook (part # 692508) if service is required on this series of carburetor.

When servicing carburetors, use the engine model and specification number to obtain the correct carburetor part number. An alternate method to find the correct carburetor part number is to use the manufacturing number and date code stamped on the carburetor and convert this number to a part number. In the carburetor section of the Master Parts Manual, Microfiche Catalog, or Electronic Parts Catalog, a cross reference chart will convert a carburetor manufacturing number to a Tecumseh part number. When using computer parts look up system, it is only necessary to enter this information in the search box using prefix OK for Tecumseh carburetors, WA or WTA for Walbro carburetors or HU for Tillotson carburetors (diag. 3-1).

OPERATION

In the "CHOKE" or "START" position, the choke shutter is closed, and the only air entering the engine flows through openings around the choke shutter. As the recoil assembly is operated to start the engine, upward piston travel creates a low pressure area in the crankcase. High pressure atmospheric air rushes into the crankcase to fill the created low pressure area. Since the majority of the air passage is blocked by the choke shutter, a relatively small quantity of air enters the carburetor at increased speed. The main nozzle and both idle fuel discharge ports are supplying fuel due to the low air pressure in the intake of the engine and the fuel side of the main diaphragm. Atmospheric air pressure on the opposite side of the main diaphragm forces the diaphragm upward, depressing the inlet control lever, overcoming inlet spring pressure and allowing fuel to enter the fuel chamber through the inlet valve. A maximum fuel flow through the carburetor orifices combined with the reduced quantity of air that passes through the carburetor, make a very rich fuel mixture which is needed to start a cold engine (diag. 3-2).

Fuel Impulse

Intake Air

Engine Vacuum

Start

3-1

3-2

At IDLE the throttle shutter is almost closed, the low pressure acts only on the primary idle fuel discharge port due to throttle plate position. A relatively small quantity of fuel is needed to operate the engine (diag. 3-3).

During INTERMEDIATE throttle operation, the secondary idle fuel discharge port supplies fuel after it is uncovered by the throttle plate. As the throttle plate opens progressively further, engine speed increases. The velocity of air going through the carburetor venturi creates a low pressure area to develop at the main fuel discharge port while diminishing the effect of the low pressure area on the engine side of the throttle plate. When the pressure at the venturi throat is less than that existing within the fuel chamber, fuel is forced through the high speed mixture orifice and out the main fuel discharge port (diag. 3-4).

At HIGH SPEED operation, the throttle shutter is in a full open position. The air velocity through the venturi increases which further lowers the air pressure at the main fuel discharge port. All discharge ports are supplying fuel as the adjustment orifices will allow (diag. 3-5).

The fuel pump diaphragm in the carburetor moves up and down by pressure changes (pulsations) caused by piston movement. The pulsations are transferred to the pump by a passage called the impulse channel. The pump diaphragm moves up drawing fuel into the pump fuel chamber during a positive pulse, and a negative pulse moves the diaphragm down forcing fuel out of the fuel chamber through the inlet needle into the metering chamber.

Fuel Impulse

Intake Air

Engine Vacuum

Idle

Fuel

Impulse

Intake Air

Engine Vacuum

Intermediate

Fuel Impulse

Intake Air

Engine Vacuum

3-3

3-4

FUEL PRIMERS

Primers used on TC/TM engines supply a solid fuel charge to the carburetor main nozzle (diag. 3-6). Fuel is forced directly into the carburetor venturi. A choke shaft and shutter is not needed or used when a primer is used. This charge of fuel provides the rich mixture necessary to start the engine.

Below the main nozzle is a one way check valve to prevent fuel from being drawn back into the fuel chamber when the primer bulb is released. The check valve also prevents air from entering the carburetor during normal engine operation.

High Speed

3-5

3-6

COMPONENTS

WALBRO CARBURETOR

1. Diaphragm Cover Screw

2. Metering Diaphragm Cover

3. Diaphragm

4. Diaphragm Gasket

5. Metering Lever

6. Metering Lever Screw

7. Metering Lever Pin

8. Metering Lever Spring

9. Inlet Valve Needle

10. Inlet Valve Seat

11. Welch Plug

12. Choke Shaft

13. Choke Shutter Screw

14. Choke Shutter

15. Idle Mixture Screw

16. Idle Speed Screw

17. Throttle Shaft

18. Throttle Shaft Return Spring

19. Throttle Shutter Screw

20. Throttle Shutter

21. Fuel Fitting

22. Fuel Inlet Screen

23. Pump Diaphragm

24. Pump Cover Gasket

25. Pump Cover

26. Pump Cover Screw

27. Tension Spring

28. Dust Seal

29. Dust Seal Washer

20 22

3-7

TILLOTSON CARBURETOR

1. Diaphragm Cover Screw

2. Metering Diaphragm Cover

3. Diaphragm

4. Diaphragm Gasket

5. Metering Lever

6. Metering Lever Screw

7. Metering Lever Pin

8. Metering Lever Spring

9. Inlet Valve Needle

10. Air Vane

11. Air Vane Screw

12. Dust Seal

13. Dust Seal Washer

14. Dust Seal Retainer

15. Idle Mixture Screw

16. Idle Speed Screw

17. Throttle Shaft

18. Throttle Shaft Return Spring

19. Throttle Shutter Screw

20. Throttle Shutter

21. Fuel Fitting

22. Fuel Inlet Screen

23. Pump Diaphragm

24. Pump Cover Gasket

25. Pump Cover

26. Pump Cover Screw

27. Tension Spring

28. Main Mixture Jet

29. Welch Plug

3-8

TECUMSEH CARBURETOR

1. Diaphragm Cover Screw

2. Metering Diaphragm Cover

3. Diaphragm

4. Diaphragm Gasket

5. Metering Lever Screw

6. Metering Lever Pin

7. Inlet Valve Needle

8. Metering Lever

9. Metering Lever Spring

10. Welch Plug

11. Dust Seal

12. Dust Seal Retainer

13. Dust Seal Retainer Screw

14. Idle Mixture Screw

15. Welch Plug

16. Dust Seal

17. Dust Seal Washer

18. Throttle Shaft Return Spring

19. Throttle Shutter Screw

20. Throttle Shutter

21. Fuel Fitting

22. Pump Diaphragm

23. Pump Cover Gasket

24. Pump Cover

25. Pump Cover Screw

26. Idle Speed Screw

27. Throttle Shaft

3-9

ENGINE TROUBLESHOOTING

Engine Will Not Start

WET

Defective Spark Plug

Restricted Air Filter

Check For Spark

YES

Check If Spark Plug Is Wet or Dry

Check Compression Release

for Stuck Open Condition

See Chapter 6

under "Troubleshooting"

DRY

Check Fuel Supply

and Fuel Cap Vent

Improper or Stale Fuel

Carburetion Problems Due to

Flooding, Over Priming, etc.

Ignition System

Plugged Muffler or Exhaust Port

Restriction in Fuel System

(filter, screen)

Carburetion Problem

Blockage in Pulse Channel to

Carburetor

Poor Compression

TROUBLESHOOTING CARBURETION—TC/TM SERIES

)

ADJUSTMENTS

)

(

Low ●●● ●●●

High ●●● ●●

FUEL SYSTEM

Plugged Tank Filter or Vent ●● ● ●●●

Restricted Fuel Line ●● ● ●●

Dirt in Fuel Passage ●●●● ●●

PEE

(

)

Loose, Damaged Fuel Line ●● ● ● ●●

Leak in Pulse System ●● ● ●●●

Restricted Pulse Channel ●● ● ●●●

Loose Pump Cover Screws ●●●●●

Defective Pump Diaphragm ●●● ●● ●

AIR SYSTEM

Plugged Air Filter ●●●●●

Defective Manifold Gasket ●● ● ●●

Loose Carburetor

●● ● ●

Mounting Bolts

Worn Throttle Shaft or Valve ●

Incorrect Throttle Assembly

Loose Throttle Valve Screw ●

Throttle Shaft Too Tight ●

Bent Throttle Linkage ●

Defective Throttle Spring ●

Bent Throttle Stop Lever ●

Choke Not Functioning Properly ●

Worn Choke Shaft or Valve ●

TROUBLESHOOTING CARBURETION—TC/TM SERIES (CONTINUED)

)

METERING SYSTEM

STA

)

(

LEVER

Worn Lever ●

Set Too High ●● ● ● ● ● ●

Set Too Low ●●●

Not Free ●●●●● ●●

EED

(

)

SPRING

Distorted ●●

Improperly Installed ●●

DIAPHRAGM

Leaking (Air/Fuel) ●●● ●●

Worn Button ●

Improper Assembly ●●●

Defective Gasket ●● ●●

Loose Diaphragm Rivet ●●

Hole in Diaphragm ●● ●●

Loose Cover Screws ●● ●●●

INLET NEEDLE & SEAT

Foreign Matter ●● ● ● ● ● ●

Binding ●● ● ● ● ● ● ● ● ●

Worn Needle Body or Tip ●● ● ● ●

NOZZLE CHECK VALVE ● ● ● ●●●

TESTING

1. After repeated efforts to start the engine using the procedure listed in the operator's manual fail, check for spark by removing the high tension lead and removing the spark plug. Install a Tecumseh Spark Plug Tester (part # 670366) and check for spark. If the spark is bright blue and fires every revolution, proceed to step # 2. If no spark, weak spark, or intermittent spark, see Chapter 6 "Ignition" under "Troubleshooting".

2. Remove the spark plug and visually check the removed spark plug for a wet condition indicating the presence of fuel mixture in the cylinder.

3. If the spark plug is dry, check for restrictions in the fuel system before the carburetor. If the spark plug is wet, continue with step #7. Check the fuel cap vent, the cap must allow air to be blown through it when testing. Using a proper draining receptacle, remove the fuel line from the carburetor inlet fitting (TC Type I) or fuel tank (TC Type II/ TM) and pull off the fuel line. Examine the fuel flow and fuel condition. Improper fuel flow indicates the fuel, fuel line, filter, or tank require cleaning or replacement.

4. Visually inspect the choke shutter for complete closing or check to see fuel flowing from the main nozzle during priming. Remove the air cleaner element or air cleaner assembly to provide access for visual inspection.

5. If the fuel flow to the carburetor is adequate and no fuel flows out the main nozzle during priming or choking, the carburetor will require service. Consult the Troubleshooting Carburetion Chart for possible causes for the lack of fuel.

6. Check the compression release on TM engines. Low compression, no fuel present on the spark plug, adequate fuel flow and a known good functional carburetor indicates an internal engine problem exists. See Chapter 7 under "Troubleshooting".

7. Check the engine compression using compression tester (part # 670358) and follow the tester's recommended procedure. Low compression, no fuel present on the spark plug, adequate fuel flow and a known good functional carburetor indicates an internal engine problem exists. See Chapter 7 under "Troubleshooting".

SERVICE

CARBURETOR PRE-SET AND ADJUSTMENT

The Walbro, Tillotson and Tecumseh carburetors used on TC engines have non-adjustable main mixture jets. Only the idle mixture may be adjustable by turning the idle mixture screw. Use the following procedure to pre-set the idle mixture screw. Turn the idle mixture screw (clockwise) finger tight to the closed position, then turn the screw counterclockwise to obtain the proper preset (diag. 3-10).

Walbro model WTA, WT 1 - 1 1/8 turns

Tillotson model HU 1 1/4 - 1 3/8 turns

Tecumseh model Fixed

Final Idle Mixture Adjustment

Start the engine and allow it to reach normal operating temperature (after 3-5 minutes). As the speed control is set at the idle position, turn the idle mixture screw slowly clockwise until the engine R.P.M. just starts to decrease. Stop and note this screw position. Turn the idle mixture screw slowly counterclockwise. The engine will increase R.P.M. Continue to slowly turn the screw until the engine R.P.M. starts to decrease. Note this position and turn the mixture screw back clockwise halfway between the two engine R.P.M. drop off positions. The idle mixture adjustment is complete.

Idle Mixture Screw

3-10

CARBURETOR DISASSEMBLY

1. Note or mark the location and sequence of the diaphragm(s), gasket(s), and the metering or pump cover. Remove the screw(s), gaskets, and diaphragms.

2. Remove the idle mixture screw. On Tillotson model HU carburetors, remove the plastic screw or brass plug over the main mixture jet and remove the main mixture jet if necessary for cleaning (diag. 3-11).

3. Use a 8-32 tap with the tapered flutes removed to turn into the brass welch plug until it bottoms and begins to turn the welch plug. Carefully pull the welch plug from the carburetor body.

4. Note or mark the location and action of the throttle and air vane, and choke shaft (if applicable). Remove the screw holding the throttle or choke shutter to the shaft. Remove the Torx T8 screw (use part # 670334) holding the air vane to the throttle shaft if applicable. Remove the clip screw, dust seal retaining clip, and throttle shaft. On some older Walbro carburetors it is necessary to remove the circlip on the end of the throttle shaft to remove the shaft (diag. 3-11).

5. Remove the inlet needle valve, metering lever, and metering lever spring by removing the retainer screw on the pivot pin (diag. 3-11).

Dust Seal

Inlet Valve Needle

Fuel Inlet Screen

Pry out plug

Dust Seal Retainer

Metering Lever

Metering Lever Pin

Metering Lever Screw

Metering Lever Spring

Dust Seal

Dust Seal Washer

Throttle Shaft Return Spring

Throttle Shaft

Note: Do not allow chisel point to strike carburetor body or channel reducer

Tension Spring

Welch Plug

Main Mixture Jet

Throttle Shutter

Idle Mixture Screw

Throttle Shutter Screw

3-11

6. Remove the fuel inlet screen and check valve screen using an "O" ring pick. Remove all welch plugs using a sharpened small chisel. Drive the sharpened chisel into the welch plug, push down on the chisel to pry the welch plug out of position. Be careful not to damage the carburetor body (diag. 3-12).

7. On Walbro carburetors, the fuel inlet fitting can be removed with a pliers using a twisting and pulling motion. Do not re-use the old fuel fitting. The fuel fitting on Tillotson carburetors is not replaceable. Do not remove. Carburetor cleaner will not affect this fitting.

8. Clean all metallic parts in carburetor cleaner. Do not exceed 30 minutes soak time. Blow out all fuel passages with compressed air. Do not use tag wire to clean the orifice in the main mixture seat assembly. The main mixture seat assembly contains a teflon disc check valve. If the disc is damaged with tag wire, the carburetor will not function properly.

CARBURETOR INSPECTION

Visually examine the throttle lever shaft and choke shaft

for wear at the bearing points in the carburetor body. Inspect the pump and metering diaphragms for hardness, fuel contamination, holes or tearing in the diaphragm. Pump diaphragm flapper valves should appear flat with no curling. Check the inlet screen and check valve screen for contamination. Check the atmospheric vent hole in the metering cover and clean if necessary.

Small Chisel

Pierce plug with tip

Welch Plug

1/8"

3-12

Check the inlet needle for wear on the taper portion of the

needle. Replace as necessary.

CARBURETOR ASSEMBLY

1. Install new inlet screen(s) using a small flat punch slightly smaller than the screen. Push in until the screen contacts the seat.

2. If removed, install the high speed jet. Use a slightly larger flat punch to install the brass welch plug over the high speed jet. The closed, tapered end of the plug goes toward the jet. Tap the brass welch plug in until it is flush with the carburetor body. Apply sealant like fingernail polish to the brass plug.

3. Install new welch plug(s) using a flat punch equal to or slightly larger than the plug. The welch plug(s) must be flattened by taps with a small hammer on the installing punch. Sealant such as fingernail polish is recommended to apply to an installed welch plug. Use sparingly and wipe off excess immediately (diag. 3-13).

4. Install the inlet needle, spring, metering lever and pin. The metering lever hooks on the inlet needle and rests on the metering spring. Install as an assembly and install the retaining screw (diag. 3-14).

5. Check the metering lever tip height using a metering lever gauge (part # 670325). The tip height should be .060" to .070" (1.52 mm to 1.77 mm) from the face of the carburetor body on Walbro carburetors. On Tecumseh and Tillotson carburetors the tip of the metering lever should be flush with surface of the carburetor body.

Inlet Needle

Metering Pin

Flat End

New Welch Plug

Carburetor Face

Metering Lever Tip

Note: Punch should be of the same or larger diameter than the welch plug.

3-13

3-14

6. Install the idle mixture screw and spring and back the screw out from the closed position 1 - 1-1/8 turns for Walbro, 1-1/4 - 1-3/8 turns for Tillotson carburetors.

7. Install the metering diaphragm, cover gasket, and cover. Place the cover gasket (over the locator pins on Walbro only) on the carburetor body, add the metering diaphragm with the long rivet head toward the carburetor body on top of the gasket, add the cover and fasten the four screws (diag. 3-15).

NOTE Do not re-use old choke or throttle plate shutter screws. New screws are treated with a dry Loctite adhesive to secure them in place.

8. Install the pump gasket over the locator pins on the pump cover, add the pump diaphragm next, and place the assembly on the carburetor body. Check to see that the locator pins fit the corresponding holes in the carburetor body. Install the pump cover retaining screw (diag. 3-15).

9. If removed on Walbro carburetors, install a new fuel inlet fitting in the same position as the original (diag. 3-15). When installing a new fitting, insert the tip into the carburetor body, then coat the exposed portion of the shank with Loctite grade A (red), then press it in squarely using support on the opposite side to prevent damage to the carburetor body or fitting. Press it in until the fitting bottoms out in the carburetor body.

1. Metering Diaphragm Cover

2. Diaphragm

3. Diaphragm Gasket

4. Pump Diaphragm

5. Pump Cover Gasket

6. Pump Cover

3-15

10. Install the choke and throttle shaft assemblies in the reverse order of removal. Visually check for proper operation of the choke and throttle.

11. If applicable, attach the air vane and torque the mounting screw to 3-5 inch pounds (.34 Nm - .57 Nm).

12. TC and TM series engines use an insulator / spacer between the carburetor and cylinder. That spacer MUST installed correctly for the fuel pump to operate (diag. 3-16). Use the appropriate style to determine the correct position of the spacer block.

NOTE

The sleeve spacers must be installed before installing the fuel tank on later TM engines.

TC TYPE II

Through Hole Toward Spark Plug

Insulator/Spacer

EARLY TM

Vacuum Channel Toward Carburetor

Through Hole Away From Spark Plug

Insulator/Spacer

Vacuum Channel Toward Cylinder

LATER TM

Sleeve Spacers

Vacuum Channel Toward Carburetor

Through Hole Away From Spark Plug

Insulator/Spacer

3-16

EMISSIONIZED TC/TILLOTSON CARBURETOR

The Tillotson carburetor is an emissions grade carb. It has a married idle and high speed circuitry with limited jet adjustments on the idle (diag. 3-17).

EMISSIONS CARBURETOR IDLE MIXTURE ADJUSTMENT PROCEDURES

The carburetor is preset at the factory at a normal setting required for initial engine operation.

Allow the engine to reach normal operating temperature (after 3-5 minutes).

Set the engine speed control in the idle position. With the engine at idle speed (Note: must be less than 2400 R.P.M. for accurate adjustment). Using a small tip screw driver that fits through the access hole in the limiter cap, adjust the mixture screw slowly clockwise until the engine R.P.M. just starts to decrease. Stop and note this screw position. Turn the idle mixture screw slowly counterclockwise. As the engine increases R.P.M. continue to slowly turn the screw counterclockwise until the engine R.P.M. starts to decrease. Note this position and turn the mixture screw back clockwise halfway between the two engine R.P.M. drop off positions.

Verify the engine will accelerate from low speed to high speed and that the idle speed remains at the desired setting.

Once adjustments are complete, center the adjustment limiter cap between the two stops and press inward to engage the limiter. The limiter will snap into position and engage the adjusting screw. All future adjustments should now be made using the adjusting slot in the limiter cap.

CAUTION

remove the limiter or to adjust the mixture screw beyond the limits of the limiter assembly. Make sure that initial adjustments are made per the above procedure prior to engaging the limiter cap.

Once the limiter cap is snapped into place it is not possible to

TC/TM, EMISSIONIZED TECUMSEH CARBURETOR

The Tecumseh emissions diaphragm carburetor has fixed main and idle jets (diag. 3-18). It uses a married idle and high speed circuitry. The idle has a metering jet that can be removed for cleaning. It is covered by a small cap that must be removed to expose the jet for servicing. No adjustments or presets are required. The idle jet should be turned until tight 5-8 inch pounds (0.5 Nm), and the cap should then be installed to cover the jet.

3-17

3-18

FUEL TANK SERVICE

TC Type II/TM engines have fuel tanks with an integral fuel screen and integral outlet fuel fitting. Integral screens or fittings are not serviceable (diag. 3-19). Some TC Type I engine models use a pressed in fuel filter or a weighted filter and a flexible fuel line in the tank. Pressed in fuel filters and fittings can be serviced using the following procedure (diag. 3-20).

1. Press the fuel fitting into the tank and feed the fuel line in until the filter can be removed through the filler neck. Remove the filter and fuel line if necessary.

2. To install a new filter and fuel line: Cut the end of the fuel line at approximately a 20° angle to make installation of the fuel line through the hole in the fuel tank easier. Push the new fuel line through the tank outlet until the fuel line protrudes through the filler neck. Cut the angled portion from the fuel line.

3. On tanks without weighted filters, push a new filter on the fuel line. For weighted filters, slide the new retaining ring on the fuel line protruding from the filler neck. Push the fitting into the line to the fitting shoulder. Slide the retaining ring over the groove in the fitting and crimp the retaining ring using a pliers.

4. Attach the fuel line and weighted fuel filter if applicable. Pull the fuel line through the tank outlet. The filter barb or the fuel fitting barb must protrude from the tank.

Lock Nut

Washer

Fuel Tank

Air Cleaner Housing

Poly Air-Cleaner

Flocked Screen

Air Cleaner Cover

Cover Screw

3-19

3-20

CHAPTER 4 GOVERNORS AND LINKAGE

GENERAL INFORMATION

TC/TM series engines are equipped with pneumatic (air vane) governors. The governor's function is to maintain a R.P.M. setting when engine loads are added or taken away. Air vane governors are controlled by the air velocity created by fins on the flywheel. Changes in the engine R.P.M. cause the air vane to move. This movement opens the throttle shaft either by a link between the air vane and the throttle plate, or the air vane is mounted directly onto the throttle shaft. The throttle is opened as the engine R.P.M. drops and is closed as the engine load is removed.

This chapter includes governor assembly linkage and speed control illustrations to aid in assembly.

OPERATION

Engine R.P.M. changes cause an increase or decrease in the air velocity created by the fins on the flywheel. The air velocity exerts pressure on the air vane while a governor spring exerts pressure against the air velocity force. The air vane pivots on the engine blower housing base or is attached to the throttle shaft of the carburetor. As an engine load is applied and the engine's R.P.M. drop, the air velocity also drops, allowing the governor spring to pull open the throttle shaft and increase engine speed (diag. 4-1).

If the engine uses a remote speed control, the bowden wire will move the speed control plunger or the throttle shaft. Moving the speed control plunger results in changing the governor spring tension which increases or decreases the engine's governed speed.

COMPONENTS

1. AIR VANE

2. BACKLASH SPRING

3. GOVERNOR LINK

4. GOVERNOR SPRING

5. MOUNTING SCREW

6. SPEED ADJUSTMENT SCREW

7. SPEED CONTROL BODY

8. SPEED CONTROL LEVER

9. SPEED CONTROL PLUNGER

TC TYPE II/TM

TC TYPE I

Air Vane

TC TYPE II/TM

TC TYPE I and EARLY TYPE II

Air Vane

4-1

Spring Hooked In Notch

Insert Throttle Link

4-2

TROUBLESHOOTING

ENGINE OVERSPEEDING

1. If the engine runs wide open (faster than normal), shut the engine off or slow it down immediately.

2. Visually inspect the air vane, linkage, carburetor throttle shaft, and speed control for debris blockage, binding, breakage, or incorrect hook-up. Check the governor spring for a stretched or distorted condition. To view the components, remove the recoil assembly and/or fuel tank if necessary. For information on the proper linkage or spring connections, review the appropriate diagrams in this section.

3. Clean, correct or replace binding or damaged parts. Set the speed control to the recommended engine R.P.M.

ENGINE SURGING

1. Try to stabilize the engine R.P.M. by holding in one position the carburetor throttle shaft on the exterior of the carburetor.

2. If the engine R.P.M. stabilizes, the governor or governor adjustment should be checked. Follow the procedure under "Governor Adjustment" in this chapter. If the engine R.P.M. does not stabilize, the engine will require additional checks. Some surging problems can be carburetor or fuel related. Additional information can be found in the troubleshooting section of Chapter 3.

3. If the problem persists after the governor adjustment, check the engine R.P.M. found on microfiche card # 30 or in the computer parts lookup. If the setting for high and low speed are within the listed specification and a slight surge is experienced, increasing the engine idle speed slightly may eliminate this condition.

4. Visually inspect the air vane, linkage, carburetor throttle shaft, and speed control for debris blockage, binding, breakage, or incorrect hook-up. Check the governor spring for a stretched or distorted condition. To view the components, remove the recoil assembly and/or fuel tank if necessary. For information on the proper linkage or spring connections, review the appropriate diagrams in this section.

SERVICE

For governor disassembly or assembly procedures see "Service" in Chapter 7.

GOVERNOR ADJUSTMENT

Three different styles of governor systems are used on TC/TM engines. Use the following illustrations (diags. 4-3, 4-4 and 4-5) to identify the governor system used and the following procedure to adjust the governed engine speed.

1. Allow the engine to run for at least 5 minutes to reach the operating temperature. Make sure the air filter (if equipped) is clean and the choke is in the off position.

2. Using a Vibratach (part #670156) or other tachometer, determine the engine's R.P.M at idle and wide open throttle. Consult microfiche card # 30 or the computer parts lookup to obtain the recommended engine speeds.

3. Using the applicable illustration, either bend the speed adjusting lever toward the spark plug end of the engine to decrease high speed R.P.M., or bend the lever in opposite direction to increase R.P.M. On TC Type II/TM engines, turn the speed adjusting screw out to increase or in to decrease engine high speed R.P.M. If the speed adjustment screw is turned out to increase the engine R.P.M., the speed control lever must be moved to allow the speed control plunger to contact the speed adjustment screw.

TC TYPE I

Spring Hooked In Notch

TC TYPE I and EARLY TC TYPE II

Spring Hooked In Notch

Speed Adjusting Lever

Decrease Increase

Speed Adjusting Lever

4. The low speed is set by moving the throttle control to the lowest speed position and adjusting the low speed adjustment screw on the carburetor.

4-3

TC TYPE I and some TC Type II

AIR VANE MUST ROTATE FREELY AFTER CLIP IS INSTALLED

ITEM DESCRIPTION 1 Base - Housing 2 Body Assy. - Speed Control 3 Screw 4 Carburetor Throttle Plate 5 Air Vane 6 Spring - Backlash 7 Link - Governor

TC TYPE II/TM

ADJUST GOVERNED HIGH SPEED WITH SPEED CONTROL PLUNGER PULLED BACK AGAINST SPEED ADJUSTMENT SCREW

DECREASE

SPEED ADJUST SCREW

INCREASE

ITEM DESCRIPTION 8 Spring - Governor 9 Clip - Spring 10 Spring and Link Attachment 11 Speed Control Plunger 12 Speed Adjustment Screw 13 Notch in Air Vane for Governor

14 Speed Control Lever

Spring Color Spring Position

Spring Attachment

4-4

Decrease (IN) Increase (OUT) Speed Adjusting Screw

Adjust governed high speed with speed control plunger pulled back against speed adjustment screw. Turn speed adjusting screw IN to decrease engine RPM or OUT to increase RPM.

Orange or Green 1

Pink, Red, or Black 2

Spring Position 1

Spring Position 2

Speed Adjusting Screw

4-5

CHAPTER 5 REWIND STARTERS

GENERAL INFORMATION

TC/TM series engines have the recoil assembly as a part of the engine's blower housing. Two different styles of recoil starters are used along with different starter rope locations. Use the engine model and specification number to identify the recoil style and correct replacement parts.

OPERATION

TC TYPE I

As the starter rope is pulled, the starter pulley rotates on the center leg of the starter. The starter pawl is connected to the starter pulley by an offset hole in the pawl and a corresponding raised boss on the pulley. The pawl has an oversized inside diameter which allows the pawl to be pulled off center. The flat contact surface of the pawl engages with one of the flywheel fins. This engagement turns the flywheel until the engine fires and the flywheel speed exceeds the speed of the starter pulley. The flywheel fins push the pawl (using the ramp side) to the disengaged position. The brake spring slows the pulley and pawl from turning (diag. 5-1).

TC TYPE II/TM

This starter uses two engagement pawls bolted to the flywheel with shoulder bolts. Each pawl uses an engagement spring to keep the pawl in contact with the pulley hub. The pawls lock into two of the four notched surfaces located on the starter pulley when the starter rope is pulled. When the engine fires and the flywheel speed exceeds the speed of the starter pulley, the pawls disengage, and centrifugal force keeps the pawls in the disengaged position (diag. 5-1).

COMPONENTS

1. Blower Housing

2. Recoil Spring

3. Washer

4. Pulley

5. Pawl

6. Brake Spring

7. Retainer

8. Retainer Screw

9. Dog Screw

10. Starter Dog

11. Pawl Spring

SERVICE

Starter related problems will require the starter to be removed from the engine to diagnose the cause. On TC Type I engines, try starter operation off the engine to see pawl engagement. Visually inspect the starter pawl, brake spring, retainer, pulley, washer(s) and rope for wear or breakage. Repair or replace as necessary. On TC Type II/ TM engines, recoil disassembly is necessary only if the pulley is worn, the recoil will not retract, or the rope needs replacement. Check starter pawl engagement on the flywheel for broken springs, sticking or bent condition, or loose pawl screws.

TC Type I

TC Type II/TM

5-1

DISASSEMBLY PROCEDURE

1. Remove the fuel tank spring and recoil assembly from the engine. On TC Type II/TM engines, the air filter and fuel tank must be removed before the recoil assembly.

5-2

2. Release the recoil spring tension on the rope by removing the staple or knot in the starter handle and slowly release the rope into the recoil housing (diag. 5-2).

3. Remove the 5/16" retainer screw. On TC Type I starters, remove the pawl retainer, brake spring, and pawl.

4. Remove the starter pulley. CAUTION! Be careful not to pull the rewind spring out of the blower housing when removing the starter pulley. The rewind spring will uncoil and expand with force if removed from the blower housing, which can cause serious injury.

ASSEMBLY PROCEDURE

1. Lightly grease the center leg and the area where the rewind spring will rest in the blower housing with "Chem-Lube" or "Lubriplate" (diag. 5-3).

Lubricate Here

5-3

2. Install a new starter spring if necessary. Securely grip the rewind spring a short distance away from the spring tail with a needlenose pliers. Position the rewind spring in the blower housing and hook the spring tail to the housing as shown. Make sure the spring tail is fully seated before slowly releasing the needlenose pliers from the spring. Push the coiled spring into the recessed boss area and discard the spring holder. Apply a thin coating of "Chem-Lube" to the top of the spring (diag. 5-4).

3. Insert the starter rope into the starter pulley and tie a left handed knot in the end of the rope. Wind the starter rope counterclockwise (as viewed from the pulley bottom) on the pulley and place the end of the rope in the notch in the pulley (diag. 5-5).

4. Place the pulley in the blower housing, press down and rotate the pulley until the pulley drops down and catches the end of the rewind spring. On TC Type II/TM models, continue assembly at step 7 (diag 5-6).

5. Lightly grease the pawl retainer and place the pawl (with the numbers up) on the retainer. Place the brake spring on the center of the retainer with the tab locating the pawl (diag. 5-7).

6. Install the retainer, pawl, and spring assembly on the center leg, locate the notch in the center leg and the tab of the retainer and align when installing (diag. 5-8).

5-5

Spring Tail

5-4

5-6

7. Insert the retainer screw and torque to 30-40 inch pounds (3.4 Nm - 4.5 Nm).

8. Use the starter rope or fingers to turn the pulley and pre-wind the recoil spring a minimum of 1-3/4 and a maximum of 2-1/2 turns in a counterclockwise rotation.

9. Feed the starter rope through the starter grommet and secure the starter handle using a left hand knot.

Spring

Pawl

Retainer

5-7

5-8

CHAPTER 6 IGNITION

GENERAL INFORMATION

All TC/TM engines are equipped with a solid state ignition module mounted outside the flywheel. The solid state ignition system consists of a flywheel magnet, charge coil, capacitor, a silicon controlled rectifier, a pulse transformer, trigger coil, high tension lead, and a spark plug. Some TC Type II modules also contain an ignition rev limiting device to prevent the engine from exceeding the maximum rpm. This type of limiter is used on mini-carts for safety reasons. All components except the spark plug and high tension lead are located in an encapsulated ignition module. The module is protected by epoxy filler from exposure to dirt and moisture. This system requires no maintenance other than checks of the high tension lead and spark plug.

OPERATION

As the magnet in the flywheel rotates past the charge coil, electrical energy is produced in the module. The energy is stored in the capacitor (approx. 200 volts) until it is released by an electrical switch (SCR). As the magnet continues to rotate, it passes past a trigger coil where a low voltage signal is produced. This low voltage signal closes the SCR switch, allowing the energy stored in the capacitor to flow to a transformer where the voltage is increased from 200 volts to 25,000 volts. This voltage flows along the high tension lead to the spark plug where it arcs across the electrodes and ignites the air-fuel mixture (diag. 6-1).

COMPONENTS

1. FLYWHEEL WITH MAGNETS

2. FLYWHEEL KEY

3. IGNITION MODULE

4. SPARK PLUG

5. IGNITION SWITCH

6-1

6-2

IGNITION TROUBLESHOOTING

SPARK

Check compression release

for stuck open condition

Check flywheel for damaged

or sheared key

Set proper air gap on solid

state module

Engine Will Not Start

Check For Spark

Equipment problem, check

switches, wiring and

equipment controls

Engine Runs Erratically

Or Shuts Off, Restarts

NO SPARK

Replace spark plug

Isolate engine and repeat

test

NO SPARKSPARK

Engine problem, check for shorts or grounds in wiring

Test solid state module for

intermittent or weak spark

Fuel system problem -

see Chapter 3 -

"Troubleshooting"

Disconnect ignition cut-off

wire at the solid state

module and repeat test

Check for proper air gap on

solid state module and

repeat test

Check flywheel magnets for

strength

Test solid state module

Tecumseh TM SERIES, TC SERIES, TC300-3133C(B)5114G, TC300 SERIES, TC200 SERIES Technician's Handbook

Specifications and Main Features

Frequently Asked Questions

User Manual