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Tecumseh Cast Iron Engine Manual


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TECUMSEH

T E C H N I C I A N ' S H A N D B O O K

This manual covers the following models:

VH80, VH100, HH80, HH100, HH120, OH120-180

Model numbers are located on the engine shroud.

Other illustrated Tecumseh 2-Cycle Engine, 4-Cycle Engine and Transmission manuals; booklets; and wall charts are available through Tecumseh.

For complete listing write or call

8 TO 18 HP CAST IRON FOUR CYCLE ENGINES

Contents

 

 

Page

CHAPTER 1. GENERAL INFORMATION

1

SECTION 1. ENGINE IDENTIFICATION

1

SECTION 2. ENGINE CARE

2

CHAPTER 2. AIR CLEANERS, CARBURETORS, GOVERNORS AND LINKAGE

4

SECTION 1. AIR CLEANERS

4

SECTION 2. GENERAL CARBURETOR INFORMATION

5

SECTION 3. TECUMSEH CARBURETORS

6

SECTION 4. WALBRO CARBURETORS

10

HH80 - 120, VH80 - 100

10

SECTION 5. OVERHEAD VALVE ENGINE CARBURETORS

13

SECTION 6. GOVERNORS

16

SECTION 7. IMPULSE FUEL PUMP

19

CHAPTER 3. REWIND STARTERS, ELECTRIC STARTERS, TROUBLESHOOTING AND GENERATORS

20

SECTION 1. REWIND STARTERS

20

SECTION 2. ELECTRIC STARTERS

22

SECTION 3. 12 VOLT STARTER TROUBLE SHOOTING CHART

25

CHAPTER 4. GENERAL VALVE INFORMATION, CYLINDER HEAD AND BREATHER ASSEMBLY

27

SECTION 1. GENERAL VALVE INFORMATION

27

SECTION 2. CYLINDER HEAD

31

SECTION 3. BREATHER ASSEMBLIES

32

CHAPTER 5. PISTON AND RINGS, CONNECTING RODS AND CRANKSHAFTS

33

SECTION 1. PISTON AND RINGS

33

SECTION 2. CONNECTING RODS

35

SECTION 3. CRANKSHAFTS

36

CHAPTER 6. CAMSHAFT, BEARINGS AND SEALS

37

SECTION 1. CAMSHAFT

37

SECTION 2. BEARINGS

38

SECTION 3. SEALS

42

CHAPTER 7. DYNA-STATIC® BALANCING SYSTEM

43

CHAPTER 8. IGNITION SYSTEMS, CHARGING SYSTEMS BATTERY SERVICE and

 

ELECTRICAL CONTROL PANELS

45

SECTION 1. IGNITION SYSTEMS

45

SECTION 2. CHARGING SYSTEMS

48

SECTION 3. BATTERY SERVICE

53

SECTION 4. ELECTRICAL CONTROL PANELS

56

CHAPTER 9. TROUBLESHOOTING

61

CHAPTER 10. 8 H.P. & LARGER ENGINE SPECIFICATIONS AND TORQUES

66

SECTION 1. CROSS REFERENCE LIST FOR TABLE OF SPECIFICATIONS

66

SECTION 2. TORQUE SPECIFICATIONS

70

8 H.P. & LARGER ENGINES (EXCEPT VALVE-IN-HEAD)

70

SECTION 3. VALVE-IN-HEAD ENGINE SPECIFICATIONS

71

SECTION 4. TORQUE SPECIFICATIONS

73

VALVE-IN-HEAD

73

CHAPTER 11. EDUCATIONAL MATERIALS AND TOOLS

74

Tecumseh Products Company

i

CHAPTER 1. GENERAL INFORMATION

SECTION 1. ENGINE IDENTIFICATION

Tecumseh engine model numbers are stamped into the blower housing, or are located on a nameplate or tag on the engine in locations as illustrated.

OH160-170033 SER 8044C

INTERPRETATION OF MODEL NUMBER. The first letter designations in a model number indicate the basic type of engine.

HH- Horizontal-Heavy Duty (Cast Iron) VH - Vertical-Heavy Duty (Cast Iron)

OH - Overhead Valve-Heavy Duty (Cast Iron)

The number designations following the letter indicates the horsepower of the engine.

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 indicates the production data.

Using model number OH160-170033, Serial 8044C as an example, interpretation is as follows:

OH160-170033 - is the model and specification number. OH - Overhead Valve-Heavy Duty (Cast Iron)

160 - Indicates 16 horsepower.

170033 - is the specification number used for properly identifying the parts of the engine.

8044C - is the serial number.

8 - first digit is the year of manufacture (1998)

044 - indicates calendar day of that year (044 day or February 13, 1998).

C - represents the line, shift or plant in which 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 tags of engines should always be transferred to a short block for correct parts identification.

1

SECTION 2. ENGINE CARE

FUELS. Use clean, fresh unleaded automotive gasoline in all Tecumseh four-cycle engines. (Leaded “regular” gasoline is an acceptable substitute.)

NOTE: Do Not use gasoline containing methanol (wood alcohol). Gasoline containing a maximum of 10 ethanol or grain alcohol (sometimes called “gasohol”) may be used but requires special care when engine is unused for extended periods.

See “STORAGE” instructions.

ENGINE OIL, ALL FOUR CYCLE ENGINES:

USE A CLEAN, HIGH QUALITY, DETERGENT OIL. Be sure original container is marked with engine service classification “SF - SJ.”

DO NOT USE SAE10W40 OIL.

FOR SUMMER (ABOVE 32°F, 0°C) USE SAE 30 OIL (SAE10W30 is an acceptable substitute.)

FOR WINTER (BELOW 32°F, 0°C) USE SAE 5W20 OR 5W30 OIL.

(SAE10W is an acceptable substitute.)

(BELOW 0°F, -18°C ONLY) Use 0W30 oil or SAE10W oil diluted with 10% kerosene is acceptable.

NOTE: For severe, prolonged, winter operation of HH120 model, SAE10W oil is recommended.

OIL CHANGE INTERVALS. Change oil after first two

(2)hours of operation and every 25 hours thereafter, or more often if operated under dusty or dirty conditions.

OIL CHECK. Check oil every 5 hours or each time the equipment is used. Position equipment so the engine is level when checking the oil.

BREAK-IN PROCEDURE. Proper break-in procedure is important for proper seating of rings, on a new engine or newly overhauled engine.

Do normal work with the unit, running the engine under load. Vary the load on the engine frequently to aid in seating of the rings.

The engine should not be allowed to idle or run at part throttle for extended periods during break-in. Work the engine but do not abuse it.

TUNE-UP PROCEDURE. The following is a minor tune-up procedure. When this procedure is completed, the engine will operate properly or you may discover that further repairs may have to be performed.

NOTE: It is recommended to use only factory parts in a Tecumseh engine. This is especially important with an air filter, since the use of any other than the specified part number may result in serious damage to the engine.

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

1.Service or replace air cleaner as necessary.

2.Inspect level and condition of oil; drain oil.

3.Remove blower housing, clean all dirt, grass or debris from intake screen, head and cylinder cooling fins and carburetor governor levers and linkage.

4.Remove cylinder head, remove carbon, inspect valves and cylinder bore. Replace head using a new head gasket. Torque to specifications.

5.Remove carburetor, clean and install carburetor kit, make adjustment pre-sets where needed. Make sure fuel tank, fuel filters and fuel lines are clean. Reinstall carburetor, replacing any worn or damaged governor springs or linkage. Make proper governor adjustment.

6.Remove flywheel, check for leaks in oil seals, check flywheel key and reinstall flywheel. Replace spark plug and check for spark.

7.Make sure all remote linkage is properly adjusted for proper operation.

8.Replace fuel and oil.

9.Run engine and adjust carburetor and set R.P.M. to specifications found on Microfiche or computer parts lookup.

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

CAUTION: NEVER STORE THE ENGINE WITH FUEL IN THE TANK INDOORS , 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 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. Fuel stabilizer (such as Tecumseh’s Part No. 730245) 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 stabilizer to allow it to reach the carburetor.

2

DRAINING THE FUEL SYSTEM:

CAUTION: DRAIN THE FUEL INTO AN APPROVED CONTAINER OUTDOORS, AND AWAY FROM ANY OPEN FLAME OR COMBUSTION SOURCE. BE SURE THE ENGINE IS COOL.

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 or fuel tank. Be careful not to damage the fuel line, fittings, or fuel tank.

2.Drain the carburetor by pressing upward on the bowl drain (if equipped) which is located on the bottom of the carburetor bowl. On carburetors without a bowl drain, the carburetor may be drained by loosening the bowl nut on the bottom carburetor one full turn. Allow to completely drain and retighten the bowl nut being careful not to damage the bowl gasket when tightening.

3.If "Gasohol" has been used, complete the above procedure and then put one half pint of unleaded gasoline into the fuel tank and repeat the above procedure. If Gasohol is allowed to remain in the fuel system during storage, the alcohol content will cause rubber gaskets and seals to deteriorate.

Change Oil: If the oil has not been changed recently, this is a good time to do it.

Oil Cylinder Bore:

1.Disconnect the spark plug wire and ground the wire to the engine. Remove the spark plug and put 1/2 ounce (14 ml) of clean engine oil into the spark plug hole.

2.Cover the spark plug hole with a shop towel.

3.Crank the engine over slowly several times.

CAUTION: AVOID SPRAY FROM SPARK PLUG HOLE WHEN SLOWLY CRANKING ENGINE OVER.

4.Install the spark plug and connect the spark plug wire.

Clean Engine: Remove the blower housing and clean all dirt, grass or debris from the intake screen, cylinder head, cylinder cooling fins, carburetor, governor levers and linkage.

3

CHAPTER 2. AIR CLEANERS, CARBURETORS,

GOVERNORS AND LINKAGE

SECTION 1. AIR CLEANERS

PAPER-TYPE AIR CLEANER SERVICE. Dry type paper air cleaners are utilized on all Tecumseh Large Frame engines. These air cleaners have treated paper elements with rubberlike sealing edges. These edges must seal properly to prevent dirt leakage.

COVER ELEMENT

BASE

SEALING EDGES

PAPER-TYPE AIR CLEANER SERVICE. Replace air filter once a year or more often in extremely dusty or dirty conditions.

DO NOT ATTEMPT TO CLEAN OR OIL FILTER.

POLYURETHANE-TYPE AIR CLEANER. Some Tecumseh Large Frame engines may use a polyurethane air filter in conjunction with a paper filter.

GASKET

SPACER BOLT

BRACKET

BACK

BOLT COVER

PAPER

ELEMENT

POLY

OUTER ELEMENT

FRONT COVER

Be sure to clean base and cover thoroughly before installing new paper filter.

NEVER RUN THE ENGINE WITHOUT THE COMPLETE AIR CLEANER INSTALLED ON THE ENGINE.

NOTE: Serious damage to the engine may result in using other than the specified part number filter. Use factory recommended parts only.

POLY-TYPE AIR CLEANER SERVICE. Clean and re-oil every 3 months or every 25 operating hours, whichever comes first. Clean daily if used in extremely dusty or dirty conditions. Proceed as follows:

Remove wing nut and cover.

Slide foam filter off paper filter.

Wash foam filter in water and detergent solution and squeeze, Don’t twist until all dirt is removed.

Rinse thoroughly in clear water.

Wrap in a clean cloth and squeeze, Don’t twist until completely dry.

Saturate foam filter with engine oil and squeeze, Don’t twist to distribute oil and remove excess oil.

Clean top side of base and inside of cover thoroughly.

Replace foam filter, cover and wing nut. Tighten wing nut securely.

NEVER RUN ENGINE WITHOUT COMPLETE AIR CLEANER INSTALLED ON ENGINE.

4

SECTION 2. GENERAL CARBURETOR INFORMATION

CARBURETOR IDENTIFICATION. Tecumseh carburetors are identified by a model number and code date stamping on the carburetor as illustrated.

ALTERNATE LOCATION

FOR MODEL NUMBER

89

3

F

89

3

F

5

 

 

 

 

 

 

CARBURETOR

CARBURETORMODEL NUMBER

CODE DATE

When servicing carburetors, use the engine model number or the model number on the carburetor and proper section in the Master Parts Manual or Microfiche Catalog for proper service information.

CARBURETOR

MODEL NUMBER

This carburetor is used on the Overhead Valve engine 12, 14, 16 & 18 horsepower.

FLOAT-FEED CARBURETORS. Float-feed carburetors use a hollow metal float to maintain the operating level of fuel in the carburetor. As the fuel is used, the fuel level in the carburetor bowl drops and the float moves downward. This actuates the inlet needle valve, to allow fuel to flow by gravity into the fuel bowl. As the fuel level in the bowl again rises, it raises the float. This float motion adjusts the fuel flow at the proper rate and keeps the fuel at the proper mixture level.

These carburetors are used on some HH80-100- 120 and VH80-100 engines.

5

SECTION 3. TECUMSEH CARBURETORS

Following are initial carburetor adjustments to be used to start the engine. After the engine has reached operating temperature make final adjustments.

Main Adjustment

HH80-100-120

Screw

VH100, 1-3/4 turns.

 

 

Idle Adjustment

HH80-100-120

Screw

VH100, 1-1/4 turns

 

 

The Master Parts Manual or Microfiche has a direct engine-to carburetor reference list. Further identification of the carburetor is stamped on the carburetor body as shown. Refer to the standard service part number and the identification number on the carburetor body, in any correspondence.

CHOKE LEVER

THROTTLE

LEVER

WELCH PLUG

CARBURETOR

MODEL NUMBER

 

CARBURETOR DISASSEMBLY, INSPECTION AND ASSEMBLY. Carefully disassemble carburetor, removing all non-metallic parts, i.e., gaskets, viton seats and needles, “O” rings, fuel pump valve, etc.

THROTTLE. Examine the throttle lever shaft and shutter prior to disassembly. Replace any worn parts.

1.Remove the screw in the center of the throttle shutter and pull out the throttle shaft lever assembly.

2.When reassembling, replace the throttle shutter with identifying marks as positioned prior to disassembly. The throttle shaft must be held in tight to the bottom bearing to prevent the throttle shutter from riding on the throttle bore of the body, causing excessive throttle shutter wear and governor hunting.

NOTE: IDENTIFYING MARK WILL BE

THROTTLEFOUND IN THE 3 O’CLOCK POSITION SHUTTER

CHOKE. Examine the choke lever, shaft and shutter prior to disassembly. Replace any worn parts.

1.Remove the screw in the center of the choke shutter and pull out the choke shaft lever assembly.

2.When reassembling, replace the choke shutter with identifying marks as positioned prior to disassembly. Hold the choke shaft securely into the bearing bore when replacing the choke shutter.

CHOKE SHUTTER CUT

OUT CLEARANCE FOR

INTERNAL VENT TUBE

IDLE ADJUSTMENT SCREW. Remove the idle screw from the carburetor body and examine the point for damage to the seating surface of the taper. Replace any damaged parts.

BAD

GOOD

 

 

 

 

 

 

 

 

 

6

HIGH SPEED ADJUSTMENT SCREW. For service, examine the taper of the high speed adjustment screw. If the taper is damaged at the area where it seats, replace the screw and fuel bowl retainer nut as an assembly.

FUEL BOWL RETAINING NUT. Remove the fuel bowl retaining nut including fiber washer.

Examine the small fuel passage in the annular groove in the retaining nut. This passage must be clean for the proper transfer of fuel into the idle metering

INLET NEEDLE. The inlet needle is anchored to the float tab by a clip, to assure proper movement of the inlet needle off of the seat when the float drops. The inlet needle clip must be positioned as shown during reassembly.

CLIP

system. Replace any worn parts.

When replacing, torque the fuel bowl nut to 50-60 inch pounds.

LONG END OF CLIP

OPEN END

OF CLIP

THROTTLE END

 

FUEL BOWL

 

FLAT OF FUEL BOWL

 

TOWARD FUEL INLET

 

FITTING

 

FIBER WASHER

TORQUE TO

FUEL BOWL

RETAINING NUT

50 - 60 INCH

 

POUNDS

“O” RING

 

BRASS WASHER

 

HIGH SPEED ADJUSTMENT

 

SPRING AND SCREW

FUEL BOWL. Check the bowl for corrosion or dirt. Replace if necessary.

The fuel bowl must be free of dirt and corrosion. When tearing down carburetor for repair, replace fuel bowl “O” ring. Before installation lubricate the “O” ring with a small amount of oil for easier installation.

The fuel bowl flat surface must be positioned on the same side of the carburetor as the fuel inlet fitting or same side as the float hinge pin to assure full travel of the float.

“O” RING

CHECK FOR

CORROSION

AND DIRT

FUEL BOWL

FLOAT. Remove the float. Examine the float for crushing or holes. Examine the float hinge bearing surfaces through which the float hinge pin passes and replace if worn.

CHOKE END

Examine the inlet needle. If any wear is evident, or any of the corners show signs of rounding, the needle should be replaced.

The inlet needle hooks onto the float tab by means of a spring clip. To prevent binding, the long, straight end of the clip should face the choke end of the carburetor as shown.

SERVICING THE VITON SEAT.

a.REMOVAL. If the seat is to be replaced use the bent end of a paper clip or wire with a 3/32'’ (.24 mm) hook. Push the hook through the Viton seat hole. Then with the hook, pull the Viton seat out. Replace with a new seat.

NOTE: A #4 crochet hook can also be used for removal.

b.INSTALLATION.

NOTE: After thoroughly cleaning the cavity, moisten the viton seat with oil.

Insert the seat with the grooved side into the cup. Press the viton seat squarely into the base with a punch.

3/32”

(.24 mm)

HOOK END

INSTALLATION OF VITON SEAT

INLET NEEDLE

INSERT THIS

SEATS AT THIS

FACE FIRST

POINT

REMOVAL OF VITON SEAT

7

HIGH SPEED NOZZLE. The carburetor body contains a main nozzle emulsion tube pressed into the carburetor body to a predetermined depth and positioned within the venturi of the carburetor. Do not attempt to remove this main nozzle. Repositioning of this nozzle will seriously affect the metering characteristics of the carburetor and will require replacement of the entire carburetor.

MAIN NOZZLE

 

EMULSION TUBE

 

DO NOT REMOVE

WELCH PLUG

 

 

 

FUEL INLET FITTING. If necessary, this fitting can be removed by pulling and twisting. Be sure to install the fitting in the same position as the original. When installing the fitting, insert tip into the carburetor body, then coat the exposed portion of the shank with Loctite grade A; then press it in until the shoulder contacts the carburetor body.

PRESS IN PARTIALLY

THEN APPLY LOCTITE GRADE A

SOME INLET FITTINGS

UTILIZED A STRAINER

CARBURETOR BODY. When removing the choke and throttle shafts, check shafts and bearings in carburetor body for wear. Any looseness in these areas can cause dirt to enter the engine and cause premature wear. If dust seals are present, these should be positioned next to the carburetor body.

To do a proper cleaning job, welch plugs should be removed to expose drilled passages. To remove the welch plug, sharpen a small chisel to a sharp wedge point. Drive the chisel into the welch plug, push down on chisel and pry plug out of position.

PIERCE PLUG WITH TIP

SMALL CHISEL

 

 

WELCH PLUG TO BE

PRY OUT PLUG

REMOVED

 

DO NOT ALLOW

ABOUT 1/8” (3.2 MM)

CHISEL POINT TO

STRIKE CARBURETOR

WIDE

BODY

 

SMALL CHISEL

When all accessories and shafts have been removed, soak the carburetor in carburetor cleaner for a maximum of 30 minutes. Blow out all passages with compressed air in the opposite direction of normal fuel flow or use a soft tag wire. Clean all metallic parts with solvent.

To install a new welch plug after cleaning, place the welch plug into receptacle with raised portion up. With a punch equal, or greater than the size of the plug, merely flatten the plug. Do not dent or drive the center of the plug below the top surface of the carburetor.

FLAT-END PUNCH

SAME OR LARGER

NEW WELCHDIAMETER OF PLUG PLUG

8

FLOAT ADJUSTING PROCEDURE

All Tecumseh carburetors with an adjustable float require the correct float height to achieve the proper operation and easy engine starts. To check the float setting, hold the carburetor in an upside down position. Remove the bowl nut, float bowl, and "O" ring. Place an 11/64" (4.369 mm) drill bit across the top of the carburetor casting on the opposite side and parallel to the float hinge pin. The float must just touch the drill bit when the bit is flush with the edge of the float. If the float is too high or too low, adjust the height by bending the tab accordingly. If the required adjustment is minor, the tab adjustment may be made without removing the float and carefully inserting a small bladed screwdriver to bend the tab.

FLOAT

FLOAT HINGE

 

AND PIN

FLOAT

SETTING

11/64” (4.369 mm)

ADJUSTING TAB

INLET NEEDLE

AND SEAT

9

SECTION 4. WALBRO CARBURETORS

HH80 - 120, VH80 - 100

WALBRO CARBURETORS. Following are initial carburetor adjustments to be used to start the engine. After the engine has reached operating temperature, make final adjustments.

Main Adjustment

HH80, 100, 120

Screw

VH80, 100, 1-1/2 turns off seat

 

 

Idle Adjustment

HH80, 100 120

Screw

VH80 100 1-1/4 turns off seat

 

 

For proper carburetion the atmospheric vent MUST be open. Examine and clean if necessary.

A sluggish engine speed control may at times be caused by dirt or paint on the throttle return spring. Clean if required.

Install the throttle plate with the numbers (if present) facing out when closed. Move the throttle shaft to the closed position, place the throttle plate on the shaft and secure with the retaining screws. The throttle should move freely. If binding is present, correct by loosening screws and repositioning throttle plate.

 

 

 

THROTTLE LEVER

THROTTLE SHUTTER

 

 

 

 

 

 

THROTTLE STOP

 

 

 

 

SCREW

MOUNTING

 

INSTALL WITH

FLANGE

 

NUMBERS OUT

 

 

 

62

 

 

 

 

 

 

 

 

29

 

 

 

 

 

Choke lever positioning is maintained by the stop spring, replace if damaged.

The fuel inlet fitting should be checked if leakage is detected in the carburetor area. Do not screw in too tight, this may crack the carburetor body. The fuel bowl drain should also be examined in event fuel leakage is detected. It may be necessary at times to replace the internal rubber seat. Examine the throttle return spring if slow engine response is noted during operation. Correct by cleaning the throttle return or realigning the throttle plate.

CHOKE STOP SPRING

THROTTLE LEVER

 

THROTTLE RETURN

CHOKE LEVER

SPRING

 

 

SECONDARY

 

IDLE DISCHARGE

 

PRIMARY IDLE

FUEL INLET

DISCHARGE

 

 

THROTTLE SHUTTER

 

FUEL BOWL NUT

FUEL BOWL

HIGH SPEED

 

ADJUSTMENT SCREW

Examine the inlet needle. “A” is a needle that is serviceable, if the tip appears damaged as “B”, replace needle and seat assembly. Tighten the inlet seat to 40 to 50 inch pounds (4.5 - 5.7 Nm). Always use a new gasket. Clean all dirt from the inlet seat cavity.

Normally the main nozzle should not be removed. It is possible to clean the carburetor with solvent and compressed air. Remove and replace the main nozzle only if the high speed needle seat is damaged or because of excessive dirt.

“B” DAMAGED

MAIN NOZZLE

EMULSION TUBE

- Replace

 

INLET

NEEDLE

“A”

INLET

SEAT

INLET SEAT

INLET SEAT CAVITY

GASKET

10

Do not remove the main nozzle. If it is necessary to remove the main nozzle to aid in cleaning, discard the main nozzle and use a service replacement nozzle with an under cut in the thread area. If the nozzle removed is under cut it can be reused. This procedure must be followed to assure delivery of fuel to the idle system.

UNDERCUT

ANNULAR

GROOVE

SERVICE

ORIGINAL

MAIN NOZZLE

MAIN NOZZLE

(REUSABLE)

DO NOT REUSE IF REMOVED

Float settings are measured opposite the float hinge. Remove float by pulling out float axle. Bend adjusting tab to correct setting. Always remove the float to make adjustments.

Examine the float hinge and axle for wear. If evident replace the parts.

FLOAT

FLOAT HINGE

 

 

AND AXLE

FLOAT

SETTING

Ô Ô

ADJUSTING

INLET NEEDLE

TAB

AND SEAT

EARLY

NEW

 

 

This shows early and new needle valve, seat, gasket, and spring assembly for large horsepower engine carburetors.

Early carburetors have a metal-to-metal needle and seat contact. The float setting for this model will be

.110'’ - .130'’ (2.794 - 3.362 mm).

New carburetors contain a viton seal in the seat and a spring on the needle. For engines with the new carburetor and having a fuel pump, the float setting is .140 (3.556 mm).

For engines with the new carburetor, without a fuel pump, the float setting is .075 (1.905 mm).

The float setting on carburetors used on vertical 8 and 10 H.P. engines is .070'’ to .110'’ (1.778 - 2.794 mm). No variance for carburetor having a fuel pump.

The gasket must fit over the float spring as shown to avoid cutting by the spring when assembled.

GASKET GOES OVER SPRING (IF EQUIPPED)

CHOKE END OF

CARBURETOR

ENDS OF SPRING

POINT TOWARD CHOKE

END OF CARBURETOR

11

When assembling the float to the carburetor body, position the needle spring on the adjusting tag so that it hangs down. Hold the float spring under tension until the carburetor body will support the slight spring tension.

NOTE: THE SPRING ENDS MUST POINT TOWARD THE CARBURETOR CHOKE END.

HOLD SLIGHT

SPRING TENSION

WITH THUMB

Ô

Position the choke shaft and shutter in the closed position prior to tightening the screws. Hard starting may be due to insufficient choking action because of a misaligned choke plate. Correct by readjusting choke plate to close completely.

A typical choke shutter found on horizontal engines is shown in the figure below. The full choke position of choke lever is counterclockwise when viewed from top of the carburetor. Note cut-out position of choke shutter.

INSTALL WITH

CCW

NUMBERS OUT

 

CHOKE SHUTTER

62

29

AIR CLEANER

MOUNTING

Figure below shows a typical choke shutter found on vertical engines. The full choke position of the choke lever is clockwise when viewing from the top of the carburetor. Note cut-out position of choke shutter.

CHOKE

CW

SHUTTER

 

AIR CLEANER

MOUNTING

NUMBERS

OPPOSITE SIDE

Prior to removing the fuel bowl nut, remove the high speed adjustment needle. Use a 7/16'’ box end wrench or socket to remove the fuel bowl nut. When replacing the fuel bowl nut be sure to position the fiber gasket under the nut and tighten securely.

Examine the tip of the high speed needle, if it appears as illustrated, replace. If the tip of the high speed adjustment needle is damaged, the seat is probably damaged. The seat is part of the main nozzle. When replacing the high speed needle the main nozzle should also be replaced.

HIGH SPEED

ADJUSTMENT NEEDLE TENSION SPRING FUEL BOWL

“A”

FUEL BOWL DRAIN

“O” RING

“B” DAMAGED (Replace)

FUEL BOWL NUT

OUTSIDE GASKET

Use new gaskets when rebuilding the carburetor. If the fuel bowl to carburetor body gasket does not seat, enlarge by stretching with 4 or 5 quick short strokes. Fiber gasket must be used between center of fuel bowl and carburetor body.

The fuel pick up passage must be clean to assure adequate fuel flow from the fuel bowl to the metering systems.

INSIDE FIBER

GASKETFUEL BOWL GASKET AND SEAT

 

MAIN

 

NOZZLE

FUEL

 

PICK-UP

FLOAT

PASSAGE

 

12

SECTION 5. OVERHEAD VALVE ENGINE CARBURETORS

Overhead valve engines utilize Walbro carburetors.

THROTTLE PLATE

CHOKE LEVER

 

THROTTLE

 

RETURN SPRING

 

IDLE SPEED

 

ADJUSTMENT

 

SCREW

CHOKE

 

 

SHUTTER

IDLE

 

ADJUSTMENT

 

SCREW

 

FUEL BOWL

ATMOSPHERIC

 

VENT OPENING

FUEL BOWL

RETAINING NUTHIGH SPEED ADJUSTMENT SCREW

CARBURETOR ADJUSTMENT. Carburetor factory adjustment should not be changed. However, if required, perform the following: with engine running (Allow engine to warm up for 5 minutes). Open throttle (speed control at “RUN” or “FAST” position). Adjust high speed adjustment screw per chart, clockwise or counterclockwise until engine runs smoothly. With control in idle or slow position, adjust idle speed adjustment screw to obtain correct idle speed. If necessary, readjust idle adjustment screw clockwise or counterclockwise until engine idles smoothly.

 

HIGH SPEED

 

CARB.

ADJ. SCREW*

IDLE ADJ. SCREW*

OH120

 

 

THRU

1 TURN*

1 TURN*

OH180

 

 

 

 

 

 

*All Adjustments Off of Seat

 

 

 

IDLE ADJUSTMENT SCREW. Close idle adjustment screw by turning clockwise. Close finger tight only. Forcing will damage screw.

OPEN IDLE ADJUSTMENT SCREW: 1 turn counterclockwise.

Start engine and with the throttle open (then return to idle position), adjust idle adjust screw one-eighth (1/8) turn at a time clockwise or counterclockwise until engine runs smoothly.

With control at “idle” or “slow” position, adjust idle speed adjustment screw to obtain correct idle speed. If necessary, readjust idle adjustment screw until engine idles smoothly.

CARBURETOR SERVICING

Throttle Shutter

Install the throttle shutter with the numbers facing out when closed. Move the throttle shaft to the closed position, place the throttle shutter on the shaft and secure with new retaining screws. The throttle should move freely. If binding is present, correct by loosening screws and repositioning throttle shutter.

THROTTLE PLATE

IDLE SPEED

 

ADJUSTMENT

 

SCREW

INSTALL WITH

NUMBERS OUT

RETAINING

SCREWS

MOUNTING

THROTTLE

FLANGE

SHUTTER

 

CHOKE SHUTTER. Position the choke shaft and shutter in the closed position to tighten the screws. Hard starting may be due to misaligned choke plate. Correct by readjusting the plate to close completely.

INSTALL WITH

CHOKE SHAFT

NUMBERS OUT

 

CHOKE

SHUTTER

AIR CLEANING

ATMOSPHERICMOUNTING VENT

HIGH SPEED ADJUSTING SCREW. Prior to removing the fuel bowl nut, remove the high speed adjusting needle. When replacing the fuel bowl nut be sure to position a fiber gasket on each side of the fuel bowl.

13

Examine the tip of the high speed adjustment screw. If the tip of the screw is damaged, the seat, which is part of the main nozzle, is probably damaged. When replacing the screw, the nozzle should also be replaced with a service replacement nozzle only.

HIGH SPEED

ADJUSTMENT SCREW

FUEL BOWL

TENSION

SPRING

“O” RING

“B” DAMAGED Replace

FUEL BOWL NUT

OUTSIDE FIBER

 

GASKET

MAIN NOZZLE. Normally the main nozzle should not be removed, if it is, clean the carburetor with solvent and compressed air. Remove and replace the main nozzle only if the seat is damaged or is excessively dirty.

If it is necessary to remove the main nozzle, discard it and use a service replacement nozzle with an undercut in the thread area. If the nozzle removed is already under cut, it can be reused. This replacement assures delivery of fuel to the idle system.

UNDERCUT

ANNULAR

GROOVE

SERVICE MAIN

ORIGINAL

MAIN NOZZLE

NOZZLE - REUSABLE

(DO NOT REUSE IF REMOVED)

 

INLET NEEDLE & SEAT. The inlet needle and seat are replaceable as an assembly. If the tip appears damaged, replace the needle and seat assembly.

MAIN NOZZLE

“A”

“B” DAMAGED

 

Replace

RE-USE CHAMFERED

INSERT EDGE

FACE FIRST

INLET SEAT

CAVITY

FLOAT

MOUNTING

INLET NEEDLE TIP

SEATS AT THIS POINT

FLOAT SETTING. Float Settings are measured opposite the float hinge. Remove float by pulling out float axle. Bend adjusting tab to correct setting. Always remove the float to make adjustments.

Replace the float and axle if wear is evident. The float must measure .275” / .315'’ (6.985 / 8.001 mm) from top of boss to surface of float (closest to center).

MEASURE AT EDGE

 

CLOSEST TO CENTER

FLOAT HINGE

Ô

 

 

 

 

AND AXLE

 

 

 

 

Ô

 

 

 

.275

(6.985 mm)

 

.315

(8.001 mm)

 

 

 

 

 

 

FLOAT

ADJUSTING TAB

INLET NEEDLE

AND SEAT

 

Position carburetor in an upright position.

If float is lower than dimensions shown in figure, bend outside tab GENTLY so float does not drop plus or minus .060'’ (1.524 mm) from base of boss.

FLOAT .060 (1.524 mm)

OUTSIDE TAB

BOSS

14

ASSEMBLING SEAT, SPRING & FLOAT. Shown below is the float, hinge pin, seat and the float spring.

DAMPER

SPRING

PIN

FLOAT

When assembling the float to the carburetor body, position the needle spring on the adjusting tang so that it hangs down. Hold the float damper spring under tension until the carburetor body will support the slight spring tension. The spring ends must point toward the carburetor choke end.

HOLD SLIGHT SPRING

TENSION WITH THUMB

FIXED HIGH SPEED CARBURETOR. On carburetors of a later design the high speed screw has been replaced by a fixed speed nut. Adjustment is made only on the idle adjustment screw since the high speed setting is fixed.

IDLE ADJUSTMENT

SCREW

FIXED SPEED NUT

WALBRO WHG. The early production OH engine was equipped with a LMH carburetor. The newer engines since 1987 have been manufactured with a WHG carburetor. Service replacements are all WHG, which include an instruction sheet covering service.

The bowl gasket must be positioned over the float spring as shown.

FUEL BOWL GASKET AND SEAT

INSIDE FIBER

FUELGASKET PICK-UP

PASSAGE

FLOAT

GASKET GOES

OVER SPRING

WHG

LMH

WHG

LMH

NEW WHG

EARLY LMH

15

SECTION 6. GOVERNORS

This Governor Assembly is used on current production HH & OH Tecumseh Engines.

SHAFT PRESSED TO GEAR

GOVERNOR GEAR

WASHERS

To position the governor gear assembly, insert the shaft opposite the flyweights into the cylinder block.

SPOOL

GOVERNOR

GEAR

FLYWEIGHT

ASSEMBLY

WASHER

Position the governor gear assembly (with washer under governor gear) to mesh with the camshaft gear. Place the governor spool (with washer under the spool) on the governor gear assembly, with the fingers of the flyweights under the rim of the spool.

GOVERNOR SPOOL

GOVERNOR SHAFT

GROOVED SLOT (INTERNAL)

GOVERNOR GEAR

FLYWEIGHT

 

There is an oil groove on the inside of the spool to prevent oil pressure from building up under the spool.

Position the governor gear and flyweight assembly on the governor gear shaft. Secure with a retaining ring. Place the governor spool on the governor gear shaft.

The spool is positioned on the governor gear shaft with the fingers of the flyweight under the rim of the spool.

Some models have an oil hole in the closed end for lubrication. CAUTION: On reassembly make sure hole is open. Other models have a groove on the inside that serves the same purpose.

PRESS GOVERNOR “GEAR SHAFT’

INTO THIS DIMENSION*

1” (25.4 mm)

*1.031” (26.187 mm)

RETAINING RING GROOVE ON MODELS WITH WASHER

OIL HOLE

(ON SOME MODELS)WASHER ON SOME MODELS

GOVERNOR

GEAR SHAFT

GOVERNOR GEAR AND

RETAINING RING

FLYWEIGHT ASSEMBLY

Remove the governor gear shaft by threading the shaft with 1/4-28 die. Place a number of washers on the shaft and turn on a nut. By tightening the nut against the washers the shaft will be pulled from the cylinder.

For old style governor assembly, position the governor gear shaft over the opening in the cylinder block and tap lightly with a hammer to start. Use a press to position. Refer to top picture for proper pressed in depth. Measure from the top of the governor gear shaft to the machined surface on the cylinder block.

16

CYLINDER COVER

GOVERNOR ROD

RETAINING RING

GOVERNOR SPOOL

CONTACTS LEVER

The governor rod is retained in the cylinder cover bushing with a retaining ring.

The governor spool moves the governor rod by contacting the lever. Outward movement of the governor spool moves the governor levers and carburetor throttle to a closed position.

The lever must contact the governor spool tightly for best governor control and for correct adjustment procedure.

BEARING WITH

BEARING END

SEAL TO OUTSIDE

FLUSH WITH CASTING

 

BEARINGS

RETAINING RING

WASHER

The governor rod on some valve-in-head model engines utilize needle bearings. If bearing(s) are removed, always install new bearing(s). Remove with 3/8'’ (9.525 mm) diameter punch and mallet. To install, tap the first bearing in until the bearing end is flush with casting. Holding a finger over hole will indicate when bearing is driven into casting far enough. Drive the outside bearing in with edge flush with outside surface of casting and seal (in bearing) at outside end.

GOVERNOR ADJUSTMENT FOR HORIZONTAL ENGINES (See Picture: Governor Adjustment for Horizontal Engines)

Move remote controls to RUN position.

Loosen Screw “A”.

Pivot plate “B” counterclockwise (ccw) and hold.

Move lever “C” to left.

Tighten screw “A” securely.

When the governor is properly set, the carburetor throttle lever will be in a wide open position when the controls are set for starting.

The governor spring is to be anchored in the bottom center hole (D) of plate “B”. Do not stretch or cut the governor spring. Above adjustments will correct any variations in governor control.

GOVERNOR ADJUSTMENT FOR HORIZONTAL ENGINES

“C”

PIVOT POINT

 

GOVERNOR

“A”

SPRING

 

MOVE TO

“B”

‘RUN’ POSITION

 

TURN CCW

GOVERNOR

ADJUSTING

SCREWS

1.SETTING VARIABLE SPEED ADJUSTING SCREW. Before attaching the bowden wire, set the engine for maximum R.P.M. (See Mfg. specifications) with engine running. Use a good tachometer. Move lever “A” clockwise until lower end strikes the adjusting screw at “1”. (See picture below)

Loosen lock nut on adjusting screw and turn in to decrease R.P.M. Turn out to increase R.P.M.

CAUTION: DO NOT EXCEED RECOMMENDED R.P.M.

2.ADJUSTING FIXED SPEED. The fixed speed adjusting screw is the optional position “2”. Adjust it by starting the engine, then loosening the locknut. Turn screw in to increase R.P.M. and out to decrease R.P.M.

IDLE

 

BOWDEN WIRE

 

FAST

CLAMP “B”

 

 

 

HOLE “B”

 

(CW)

 

 

 

 

HOLE “C”

ADJUSTING SCREW

FIXED SPEED

POSITION “2”“A” LEVER

OPTIONAL

PIVOT (CW)

BOWDEN WIRE

ADJUSTING SCREW VARIABLECLAMP “C” SPEED POSITION “1” STANDARD

17

VERTICAL CRANKSHAFT GOVERNOR ADJUSTMENT.

Move remote controls to RUN position.

Loosen screw “A”.

Turn plate “B” counterclockwise (ccw) and hold.

Move lever “C” to left.

Tighten screw “A” securely.

ADJUSTING FIXED SPEED. The fixed speed adjusting screw is the optional position “2”. Adjust it merely by starting the engine and after loosening the lock nut turn screw in (clockwise) to increase spring tension and hold engine at higher R.P.M. and out (counterclockwise) to decrease tension on spring and allow speed to be decreased more easily.

“FIXED SPEED”

BOWDEN WIRE

When the governor is set properly the carburetor throttle will be in wide open position.

CLAMP “B”

HOLE “C”

GOVERNOR ADJUSTMENT VERTICAL

ÔTHROTTLE TOWARD

THROTTLE TOWARD Ô

FULL OPEN

FULL CLOSED

GOVERNOR

 

SPRING

 

LEVER “C”

 

SCREW “A”

 

 

“D”

PLATE “B”

GOVERNOR

ADJUSTING

 

 

SCREWS

TURN CCW

 

VARIABLE SPEED ADJUSTMENT. Before attaching the remote speed control (bowden wire) set the engine for maximum R.P.M. (See Mfg. specifications). Use a good tachometer.

Move lever “A” clockwise until lower end strikes the adjusting screw “1”.

Loosen lock nut on adjusting screw “1” and turn in (clockwise) to decrease R.P.M. and out counterclockwise to increase R.P.M.

CAUTION: DO NOT EXCEED RECOMMENDED R.P.M.

 

BOWDEN

HOLE “B”

WIRE

CLAMP “C”

 

“A” LEVER

ADJUSTING SCREW

ADJUSTING SCREW

FIXED SPEED

VARIABLE SPEED

POSITION “2”

POSITION “1”

(OPTIONAL)

(STANDARD)

18

SECTION 7. IMPULSE FUEL PUMP

IMPULSE FUEL PUMP. This pump is mounted onto the carburetor inlet and has connections from the fuel supply and also a pulse line to the engine crankcase.

CAUTION: IN ORDER FOR THE PUMP TO OPERATE SATISFACTORILY THE CORRECT OIL LEVEL IN THE CRANKCASE MUST BE MAINTAINED. TOO MUCH OIL WILL ADVERSELY EFFECT THE PUMPS OPERATION.

It is operated by changing pressure created by the engine piston movement and transmitted to the pump through a pulse line. The increasing and decreasing pressures acting on the diaphragm and flap valves lift fuel from the fuel tank to the carburetor of the engine.

 

 

 

 

 

CARBURETOR FITTING

 

 

 

 

 

VALVE OPEN

VALVE

 

 

 

 

 

DIAPHRAGM

ATMOSP

HERIC

 

 

 

 

CLOSED

 

 

 

 

 

 

VENT

 

FILTER

 

 

 

 

 

 

 

 

 

 

 

 

 

AIR BLEED

 

 

 

 

 

 

VALVE CLOSED

VALVE

 

 

 

 

 

PULSE LINE

OPEN

 

 

 

 

 

 

FUEL SUPPLY

 

TO CRANKCASE

 

 

±CRANKCASE PRESSURE

 

±CRANKCASE SUCTION AND

Ü SUCTION FUEL FLOW

 

 

 

 

 

 

 

FLOW DIRECTION

DIRECTION

Ô ATMOSPHERIC PRESSURE

Ô ATMOSPHERIC PRESSURE

Ô ATMOSPHERIC PRESSURE

 

ACTING ON DAMPING

 

ACTING ON DAMPING

CAUSED FUEL FLOW

 

DIAPHRAGM

 

DIAPHRAGM

 

ÜFUEL FLOW

 

 

 

To service, separate the pump by removing the four

(4)screws. Clean all new parts with a solvent and install a new kit which consists of coil springs, gaskets and diaphragms.

The diaphragms must be installed against the center body with the gaskets against the outside covers. The parts are designed so they cannot be misassembled without damage.

To test the unit, assemble the carburetor to the engine, leaving the pump off. Connect gravity fuel feed supply to the carburetor. With the pulse line connected to the pump and engine running, a definite flow should result.

If the flow is erratic or intermittent, the pump needs repair or replacement.

FOUR SCREWS INTO

BACKSIDE OF PLATE

TO BACKSIDE

OF PLATE

WHEN ASSEMBLED

THIS SIDE FACES INTO

CONCAVE CAVITY OF

ABOVE ASSEMBLY

SPRING IN

HOLE CAVITY

BUTTON WITH SPRING

TYPE I

PREVIOUS STYLE

NEW STYLE

TYPE I

TYPE II

The new style pump (TYPE II) will replace older (TYPE

I)pumps. An assembly kit is available with instructions and all the parts needed to convert to the new style. If a complete replacement of an old style is not necessary, a repair kit is still available.

19

CHAPTER 3. REWIND STARTERS, ELECTRIC STARTERS,

TROUBLESHOOTING AND GENERATORS

SECTION 1. REWIND STARTERS

REWIND STARTER DISASSEMBLY PROCEDURE

1.Clamp starter in a vise and pull rope out, and clamp pulley.

2.Untie knot in rope and remove.

3.Slowly release spring tension.

4.Remove retainer screw, retainer cup; starter dog and spring, and brake spring.

5.Lift out pulley, turn spring and keeper assembly to remove from housing.

Replace all worn or damaged parts.

BRAKE SPRING

RETAINER

WASHER

RETAINER

RETURN

SPRING

PULLEYSTARTER

DOGS

SPRING REPLACEMENT. Disassemble the starter completely.

New springs are enclosed in retainers. Be sure spring is positioned with wrapping in direction as illustrated. Position new spring and retainer over housing and press the spring out of the retainer into the starter housing.

APPLY LIGHT

REWIND

LUBRICANT

SPRING

REASSEMBLY. Lubricate the recoil spring and center shaft with a small amount of light grease. Place the pulley over the center shaft and bottom. Insert a 1/8'’ (3.175 mm) punch or rod into the through hole in the pulley, and turn the pulley. This will aid in positioning and engaging the spring.

1/8” (3.175 mm)

PUNCH

TURN PULLEY

INSERT PUNCH INTO

THROUGH HOLE AIDING

SPRING ENGAGEMENT

REWINDING SPRING AND REASSEMBLY. Place the large washer, 1-3/8'’ (34.925 mm) over the center shaft. Insert the dogs, so that they will fold in close to the center. Press the brake spring on the retainer. The brake spring must be a tight fit on the retainer. Hold the retainer and brake spring assembly at an angle to engage the return spring to the dowel on the pulley. Secure with the center screw and washer and tighten securely. Failure of the starter to engage may be traced to either a loose center screw, or loose brake spring. Tighten the screw or replace the brake spring. Replace the rope as outlined.

20

VISE

SCREW DRIVER

PREWIND

7TURNS INSERT ROPE

CLAMP WITH PLIERS TO

RETAIN TENSION

ROPE REPLACEMENT. Prepare the rope, place a thin 3/4'’ (19.05 mm) diameter washer with a 1/4'’ (3.175 mm) hole on the rope and tie a knot. The other end of the rope should be thinned to a point for easier threading.

Clamp the starter in a vise, upside down, by one leg opposite the rope outlet. Place a screw driver in the rope hole of the pulley and turn counterclockwise until tight, then allow to unwind until hole in pulley for rope lines up with hole in housing. Clamp the pulley in this position with lever action pliers. Clamp over starter housing and pulley, protect the painted surface.

Insert the rope into the pulley hole and guide it with needle nose pliers through the rope outlet in the housing. Secure the handle with a double knot. Hold the rope taut, release the pliers and allow the rope to wind on the pulley.

CENTER SCREW

STARTER DOG

WASHER

ASSEMBLING STARTER TO ENGINE. It is important to center the starter hub containing the starter dogs in the center cup so there is equal contact on all the dogs into the teeth of the cup.

Before securing the starter with the mounting screws, place the hub into the cup then pull the rope enough to cause the starter dogs to equally engage in the teeth. With the dogs securely in the cup, tighten the mounting screws to 40-60 inch pounds (4.5 - 6.8 Nm) torque. If mounting holes do not line up, blower housing is bent and must be replaced.

TIGHTEN STARTER MOUNTING SCREWS AFTER HUB IS CENTERED IN CUP

STARTER

STARTER

CUP

HUB

STARTER

STARTER DOGS EQUALLY SECURE IN TEETH FOR CORRECT CENTERING OF STARTER HUB

ON SOME VALVE-IN-HEAD ENGINES:

PULLEY (SHEAVE-TYPE) STARTER. Consists of

arope sheave-type. The engine comes equipped with starter rails and the blower housing is constructed with a removable plate for conversion to an electric start.

21

SECTION 2. ELECTRIC STARTERS

STARTER SERVICE, DISASSEMBLY AND INSPECTION. Part No. is found on identification tag. Used on large frame vertical and horizontal engines.

PART NO.

Repair of these starters consists of replacement of parts shown in the exploded view.

1.Testing

Test 12 Volt starters under the following conditions:

a.Conduct test with fully charged battery.

b.Engine and oil temperature approximately 70° F (21°C).

c.Engine contains recommended oil.

d.Cranking test not to exceed 10 seconds.

e.Parasitic loads removed from engine.

MODEL

AMPERES

ENGINE RPM

 

 

 

33835

70 MAX.

600 MIN.

 

 

 

HOUSING & ARMATURE NOT AVAILABLE

ORDER COMPLETE SYSTEM

Test and trouble shooting procedures for 12 volt starters can be found in other Sections of this chapter.

2.Disassembly.

a.Remove two (2) lock nuts from thru bolts on drive end of starter.

b.Grasp drive end of starter and remove from housing as an assembly.

HOUSING

LOCK NUTS (2)

THRUST

WASHER

DRIVE END

c.Remove dust cover, retaining ring, spring retainer, anti-drift spring, gear and engaging nut. Remove drive end cap from armature.

ENGAGING NUT

ARMATURE

 

 

LOCK NUTS (2)

SPRING

THRUST

GEAR

 

WASHER

RETAINING

THRUST WASHER

RING

 

DRIVE END CAP

SPRING RETAINER

DUST COVER

d.To remove end cap assembly, loosen the nut on terminal post. Remove the lock nuts and thru bolts from starter housing. Remove brushes or brush card separately or as an assembly.

NOTE: Care must be taken in removing and reinstalling brush springs to eliminate damage to spring and malfunction of brushes.

3.Inspection

Inspect, clean and replace parts if necessary. Test motor parts for open and shorted circuits.

22

BRUSH CARD

BRUSH AND BRUSH

SPRING (4)

TERMINAL

POST

THRU BOLTS (2)

 

COMMUTATOR

LOCK NUTS (2)

END CAP

4.Assembly

a.Install drive end cap, engaging nut and gear, anti-drift spring, spring retainer, retaining ring, and dust cover to armature. Install armature into housing.

b.Install brush card assembly and two (2) thru bolts so stops on bolts will secure brush card. Secure lock nuts on drive end of starter.

c.Install thrust washer on armature and install commutator end cap. Insure that the two- piece grommet is properly installed to prevent moisture from entering this area.

d.Install end cap lock nuts.

COMMUTATOR

END CAP

LOCK NUTS (2)

TWO PIECE GROMMET

AND TERMINAL BOLT

When using starter motor, part no. 33835 to replace starter part no. 32817 on vertical crankshaft models, proceed as follows.

1.Remove the two (2) 5/16-18 x 7/8'’ (22.225 mm) screws that attached the original starter and discard.

2.Install the 5/16-18 x 1-3/8'’ (34.925 mm) adjusting bolt through the hole in the starter bracket with a lock nut on each side of the bracket. Position bolt so head will not touch cylinder when starter is installed.

3.Install motor with two (2) 5/16-18 x 5/8'’ (115.875

mm)screws and lockwashers. Torque screws to 140-170 inch lbs. (18.2 - 19.2 Nm).

4.Turn adjusting bolt so head of bolt securely bottoms on cylinder. Tighten nuts to hold bolt in position.

NEW STARTER MOUNTING SCREWS AND WASHERS

LOCK NUT

ADJUSTING BOLT

CYLINDER

STARTER MOTOR TESTS

a.Preliminary Tests

Before checking the starter motor perform the following preliminary checks:

1.Battery must be at least 3/4 full charge.

2.Determine parts such as switch, solenoid, between power source and starter motor are in good working order.

3.Terminals must be bright and clean for full conductance.

4.Check wires for breaks, insulation breakdown.

5.Proper size (gauge) wire between power source and starter motor.

6.If starter motor does engage the flywheel but fails to crank engine, check the engine for excessive friction caused by a seized rod or piston.

7.Check related parts such as clutches, pulleys, etc. for excessive friction.

b.Visual Checks

Make a visual check of the starter motor before checking electrically. Remove the starter motor and check for freedom of operation by turning the shaft. Look for:

1.Worn out brushes.

2.Weak brush springs.

3.Dirt on the commutator bars.

4.Armature binding, caused by dirt or bushings being gummed up through excessive lubrication.

STARTER CHECKING AND SERVICE. Remove nuts at both ends of starter and take off rear end cap.

CHECK FIELD. Using a continuity light or ohm meter, check field by attaching one lead to each field coil connection. Continuity should exist between these two points. Check continuity between each field coil connection and the starter housing. No continuity should exist.

23

ARMATURE CHECK. If commutator bars are glazed or dirty they can be turned down in a lathe. While rotating, hold a strip of 00 sandpaper lightly on the commutator, moving it back and forth. (Do not use emery cloth). Recut grooves between commutator bars to a depth equal to the width of the insulators.

Using a continuity tester to make certain no continuity exists between the commutator (copper) and the iron of the armature, rotate armature and check out all commutator bars.

The armature can be thoroughly checked with a growler if available.

CHECK BRUSHES. Before removing armature, check brushes for wear. Make sure brushes are not worn to the point where the brush wire bottoms out in the slot of the brush holder. Brush springs must have enough strength to keep tension on the brushes and hold them against the commutator.

If brushes need replacement, remove by unhooking terminals or clipping connections and resoldering. If brush card is warped from overheating, replace the brush card assembly.

BRUSH CARD

BRUSH AND BRUSH

SPRING (4)

TERMINAL POST

INSTRUCTIONS FOR REPLACING STARTER BRUSH CARD #33848 ON STARTER #33835

1.Loosen the two nuts on the starter terminal post, but do not remove.

2.Remove the nuts holding the starter and cap in place. Remove the starter end cap. Note the thrust washer on the end of the armature.

3.With a pliers or vise grip tool, grasp the through- bolts as close to the flanged end as possible (away from the threaded end), and remove the two nuts retaining the driving end cap of the starter. Remove the armature and driving cap assembly. Remove the two through-bolts, noting the position of the brush ground eyelet under the through- bolt flange.

4.Note the position and the connections of the brush wires. Clip the solid field wires as close to the connectors as possible.

5.Remove the brush card from the starter, noting the position of the clearance slot. Clean the starter and all parts of accumulated dust and dirt. Scrape the insulating varnish off of the solid field wires, back approximately 1/2” (12.7 mm) from ends.

6.Insert the new brush card into position, guiding the solid field wires through the proper slots in the brush card.

7.Using the proper crimp connector, crimp and solder the remaining brush leads to the solid field wires. Use a pair of pinchers or needle-nose pliers to hold the woven brush lead adjacent to the connector while soldering (this provides a heat sink so that solder does not flow up the brush lead). Using electrical tape or shrink tubing, insulate the crimped connection nearest the starter terminal post. Position the wires to prevent shorts or grounding of the starter.

8.Spread the brushes to install the armature into the housing, and replace the starter through- bolts, being sure to install them through the ground brush eyelet terminals. Install and tighten the drive end through-bolt nuts. Tighten securely, but do not over tighten as this may warp the new brush card and impair brush movement.

9.Replace the thrust washer on the end of the armature and replace the starter end cap. Install the starter end cap locking nuts and tighten securely. Tighten the nut on the starter terminal post.

10.Test the starter for proper operation before reinstallation on the engine.

24

SECTION 3

12 VOLT STARTER TROUBLE SHOOTING CHART

PROBLEM

PROBABLE CAUSE

FIX

 

 

 

Does not function

Weak or dead battery

Check charge and/or replace battery.

 

Corroded battery terminals

Clean terminals and/or connections.

 

and/or electrical connections

 

 

Brushes sticking

Free brushes. Replace worn brushes and

 

 

those that have come in contact with grease

 

 

and oil.

 

Dirty or oily commutator

Clean and dress commutator.

 

Armature binding or bent

Free armature and adjust end play or replace

 

 

starter.

 

Open or shorted armature

Replace starter.

 

Shorted, open or grounded

Replace starter.

 

field coil

 

 

Loose or faulty electrical

Correct.

 

connections

 

 

Load on engine

Disengage all drive apparatus and relieve all

 

 

belt and chain tension.

 

Electric starter cranks but no

Disconnect ignition cutoff wire at the engine.

 

spark at spark plug.

Crank engine. If spark at spark plug ignition

 

 

switch, interlock switch and safety switch is

 

 

inoperative. If no spark, check magneto. Check

 

 

wires for poor connection cuts or breaks.

 

Electric starter does not crank

Remove wire from starter. Use a jumper battery

 

engine

and cables and attach directly to starter. If

 

 

starter cranks engine the starter is okay; check

 

 

solenoid, starter switches, safety switches and

 

 

interlock switches. Check wires for poor

 

 

connections, cuts or breaks.

 

 

 

Low RPM

Unit controls engaged

Insure all unit controls are in neutral or

 

 

disengaged.

 

Worn bearings in cap assemblies

Clean bearings or replace cap assemblies.

 

Bent armature

Replace starter.

 

Binding armature

Free up armature. Adjust armature end play.

 

Brushes not seated properly

Correct.

 

Weak or annealed brush springs

Replace springs.

 

Incorrect engine oil weight

Insure the correct weight of oil is being used.

 

Dirty armature commutator

Clean commutator.

 

Shorted or open armature

Replace starter.

 

Loose or faulty electrical

Correct.

 

connections in motor

 

 

 

 

Motor stalls under load

Shorted or open armature

Replace starter.

 

Shorted field coil

Replace starter.

 

 

 

25

12 VOLT STARTER TROUBLE SHOOTING CHART (Cont.)

PROBLEM

PROBABLE CAUSE

FIX

 

 

 

Intermittent operation

Brushes binding in holders

Free up brushes. Replace worn brushes and

 

 

those that have come in contact with grease and

 

 

oil.

 

Dirty or oily commutator

Clean and dress commutator. Replace any brush

 

 

that has come in contact with grease or oil.

 

Loose or faulty electrical

Correct.

 

connections

 

 

Open armature

Replace starter.

 

Break in electrical circuit

Disconnect ignition cutoff wire at the engine.

 

 

Crank engine. If spark, check ignition switch,

 

 

safety switch, and interlock switch. Check wires

 

 

for poor connections, cuts or breaks.

 

 

 

Sluggish

Dirt and oil on drive assembly

Clean drive assembly and armature shaft and

disengagement of the

and at armature shaft

lubricate shaft splines.

drive assembly

 

 

pinion gear

 

 

 

Bent armature

Replace starter.

 

 

 

26

CHAPTER 4. GENERAL VALVE INFORMATION, CYLINDER HEAD AND BREATHER ASSEMBLY

SECTION 1. GENERAL VALVE INFORMATION

Adjusting valves for 8 horsepower and larger engines (except valve-in-head engines)

Intake valve gap .010, (.254 mm) exhaust valve gap

.020, (.508 mm) set when engine is cold. Rotate the engine to Top Dead Center of the compression stroke, this will assure that the lifter is not raised by the compression relief pin. Valve stem ends must be ground flat when adjusting valve gap. An uneven or concave end can cause abnormal wear to the valve train.

The outside of the valve stem guide also guides the valve spring. A valve spring cap is used only on the bottom of the spring. A pin through the valve stem retains the spring.

Use a step type reamer to enlarge valve guides if worn. Oversize valves are 1/32'’ (.787 mm) larger in diameter than standard. (For oversize reamer, Consult Chapter 11).

Do not enlarge the valve lifter guide, lifters with oversize stems are not available.

 

 

VALVE GUIDE MAY BE

 

 

OVERSIZED 1/32” (.787 mm)

 

 

VALVE STEM

 

 

AND SPRING

 

 

GUIDE

 

 

VALVE CAP

 

 

VALVE LIFTER GUIDE

EXHAUST

INTAKE

DO NOT OVERSIZE

VALVE GAP

VALVE GAP

 

.020 (.508 mm)

.010 (.254 mm)

OIL RETURN HOLE

COLD

COLD

 

ADJUSTING VALVES ON OVERHEAD VALVE ENGINES. Remove the breather and top half of the valve cover. Rotate the engine to Top Dead Center of the compression stroke. Adjust the exhaust valve to .010 (.254 mm) and .005 (.127 mm) for the intake valve.

Assure that the locknut is loosened before attempting to turn adjusting screw. After the locknut is loosened, turn the adjusting screw with an open end wrench. Turn adjusting screw clockwise to decrease clearance and counterclockwise to increase clearance.

TURN ADJUSTING SCREW: CLOCKWISE TO DECREASE LASH, COUNTERCLOCKWISE TO INCREASE LASH.

ROCKER ARMS

LOCKNUTS

 

FEELER

GAUGE

VALVE STEM

ADJUSTING

 

SCREW

INTAKE .005 (.127 mm)

 

EXHAUST .010 (.254 mm)

 

VALVES. Valves must be in good condition, properly sealing and the proper gap must be maintained for full power, easy starting and efficient operation.

VALVE REMOVAL On 8 H.P. and Larger (except valve overhead engines). To remove valves, raise the lower valve spring caps, while holding the valve head tightly against the seat, and remove pin.

27

VALVE REMOVAL PROCEDURE FOR VALVE-IN- HEAD ENGINES.

The following is necessary for cylinder head disassembly.

REMOVAL OF ROCKER ARM HOUSING PARTS. Locate the piston at top dead center for easier access in servicing the valve train. After removing the rocker arms by removing the retaining rings, it may be necessary to loosen the locknut and back off the adjusting screw before pulling off the rocker arms. NOTE: Rocker arm shaft is not an inseparable unit from the rocker arm housing and should not be removed from the housing.

LOWER VALVE

UPPER VALVE

PUSH RODS

SPRING CLIP

SPRING CAP

 

 

 

VALVE SPRING

ROCKER ARM SHAFT

REMOVAL OF VALVE SPRINGS. Use a valve spring compressor tool, part No. 670237A to compress the valve spring and remove the valve retainers. Be sure piston is at T.D.C. The valve cap is then taken off for removal of the spring. When reinstalling the valve cap and retainers after valve servicing, it may be necessary to hold both valves in their seats until the springs, cap, and retainer have been installed on the valve stems. Access can usually be gained through the exhaust and intake manifold in the head.

RETAINERS HELD BY SPRING

 

TENSION AGAINST THE CAP

RETAINER

 

CAP

 

VALVE SPRING

COMPRESSOR TOOL

PART NO. 670237A

REMOVAL OF ROCKER ARM HOUSING. Remove rocker arm housing by removing the retaining cap screws. The valve spring retainer cupped side must be facing in the up position.

A white Teflon “O” Ring is used under the valve spring retainer on the exhaust valve. The regular black rubber “O” Ring is used under the valve spring retainer on the intake valve. Be careful not to switch rings, or damage may result.

Remove head to remove the valves - Reverse procedure for reassembly.

VALVE SPRING

CHAMFER

“O” RING

RETAINER

 

 

ROCKER ARM HOUSING RETAINING SCREWS,

WASHERS AND SEALING “O” RINGS

ROCKER ARM SHAFT. The rocker arm shaft is not a replaceable part. The rocker arm housing, rocker arm shaft and screw are an inseparable assembly.

ROCKER

ARM SHAFT

RETAINING

SCREW

VALVE SPRINGS FREE LENGTH

FOR 8 HORSEPOWER AND LARGER ENGINES (EXCEPT VALVE-IN-HEAD ENGINES). Valve springs should be replaced when an engine is overhauled. Weak valve springs will spoil the best overhaul job.

Valve spring free length should be checked. Comparing one spring with the other can be a quick check to notice any difference. If a difference is noticed, carefully measure free lengths and strength of each spring. See specifications.

Check valve spring free length, it should be 1.885'’ (47.879 mm). If both ends are not parallel, replace with new springs.

28

VALVE INSTALLATION. To reinstall valves, position valve caps and spring in the valve compartment. Valve spring free length should be checked and installed so the dampening coils are located opposite the keepers.

INSTALL PIN Release valve spring tension to lock cap in place.

FOR 8 HP AND LARGER (EXCEPT VALVE-IN-HEAD)

 

SPRING MUST BE SQUARE

FREE

 

LENGTH

 

1.885”

DAMPENING COILS

(47.879 mm)

LOCATED CLOSER

 

 

TOGETHER

DAMPENING COILS ON VALVE SPRINGS. The valve spring should be assembled so the dampening coil is located to the stationary end of the spring (opposite the cap and retainers).

VALVE-IN-HEAD SPRINGS. Check valve spring free length, it should be 1-15/16'’ (49.225 mm) long. If both ends are not parallel, replace with new springs.

SPRING MUST BE SQUARE

FREE

 

LENGTH

DAMPENING COILS

1.938”

LOCATED CLOSER

(49.225 MM)

TOGETHER.

 

 

POSITION TOWARD

 

VALVE BOX.

FOR VALVE-IN-HEAD ENGINES

VALVE GRINDING. Valve grinding procedures are the same for all 8 horsepower and other engines. (Including overhead valve engines). See Chapter on specifications.

Correct valve grinding procedures are essential to obtain a satisfactory result.

Face and seat angles must be accurate and the surfaces must be smooth.

A 1/32” (.787 mm) margin must be left on the valve head after refacing. The valve without a margin would burn and distort very rapidly.

Use a “Vee” block and the flat side of a grindstone to grind valve clearance. The end of the stem must be flat and true or abnormal wear will occur.

MARGIN

 

NO MARGIN

1/32”

 

 

 

 

 

 

(.787 mm)

 

 

FACE

WRONG

 

 

 

 

45°

 

 

MUST BE FLAT

 

 

STANDARD STEM

AND TRUE

STEM

DIAMETER

 

 

 

SEE SPECIFICATIONS

 

OVERSIZE STEM

MUST BE FLAT

 

DIAMETER

 

AND TRUE

 

SEE SPECIFICATIONS

WRONG

 

 

 

 

 

 

IMPORTANT: GRIND FLAT TO OBTAIN

 

 

CORRECT VALVE CLEARANCE

VALVE SEATS. Valve seats are not replaceable. If they are burned or pitted, they can be recut using a Neway valve and seat cutter. Seats are cut to an angle of 46°. If the seat is over 3/64'’ (1.194 mm) wide after cutting, use a 30° cutter to narrow the face.

ALWAYS DEGLAZE

CYLINDER WALL

SEE SPECIFICATIONS

SECTION FOR

DIMENSIONS

46° ANGLE

VALVE SEAT IN CYLINDER

VALVE SEAT CUTTING REQUIREMENTS. Cut valve seats to 46° and valve to 45°. See Specifications.

VALVE SEAT 46°

EXHAUST

INTAKE

VALVE SEAT IN HEAD

VALVE GUIDE DIMENSIONAL CHECK. Check dimensions per specification requirements, determine if valve guide clearance is beyond acceptable tolerance. If valve guide clearance is worn beyond tolerance, ream valve guide oversize and install 1/32'’ (.787 mm) oversize valve, or replace valve guides.

29

THIS SYMBOL POINTS OUT IMPORTANT SAFETY INSTRUCTIONS WHICH IF NOT FOLLOWED COULD ENDANGER THE PERSONAL SAFETY AND/OR PROPERTY OF YOURSELF AND OTHERS. READ AND FOLLOW ALL INSTRUCTIONS.

VALVE GUIDE REMOVAL AND INSTALLATION INSTRUCTION FOR VALVE-IN-HEAD ENGINES.

REMOVING THE OLD VALVE GUIDES

1.Submerge the head in a pan of oil so that both guides are covered with oil.

2.Heat oil on a hot plate until the oil begins to smoke. About 15 to 20 minutes. 375° (190°C) - 400° (204°C).

3.When the oil begins to smoke, remove the head from the pan of oil with a pair of pliers. Drain excess oil.

4.Place head on the bed of an arbor press on parallels with the snap rings on the long ends of the guides facing down.

5.Use a 1/2'’(25.4 mm) diameter, 6'’ (152 mm) drift- punch and the arbor press to push valve guides out of the head.

GUIDES

HEAD

OIL

HOT PLATE

HEAT UNTIL OIL BEGINS TO SMOKE.

CAUTION - When locating the drift punch on the guides be sure to center the punch. DO NOT allow the punch to make contact with the head when pressing out the guides.

VALVE GUIDES

1/2” (12.7 mm) FLAT DRIFT PUNCH

CENTER PUNCH DRIFT ON VALVE GUIDE

INSTALLING NEW GUIDES

NOTE For easy installation, the replacement guides should be placed in the freezer compartment of a refrigerator or on ice for no less than 30 minutes prior to installation.

1.Submerge head with guides removed in a container of oil so that both guide bores are covered with oil.

2.Heat oil on a hot plate until the oil begins to smoke. About 15 to 20 minutes.

3.When the oil begins to smoke, remove the head from the pan with a pair of pliers. Drain excess oil.

4.Place head, with gasket surface down, on a piece of wood, 6 x 12 inches (152 X 304 mm).

5.Remove the new guides from cold storage and install snap rings used for locating both valve guides. Insert the guides. It may be necessary to use a rubber or rawhide mallet to fully seat the guides to the snap ring depths in the head. DO NOT use a metal hammer head, or guide damage will result.

6.Allow head assembly to cool; recut both valve seats.

30