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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,
Model numbers are located on the engine shroud.
Other illustrated Tecumseh
For complete listing write or call
8 TO 18 HP CAST IRON FOUR CYCLE ENGINES
Tecumseh Products Company
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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.
INTERPRETATION OF MODEL NUMBER. The first letter designations in a model number indicate the basic type of engine.
HH-
OH - Overhead
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
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
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,
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.
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
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
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
COVER ELEMENT
BASE
SEALING EDGES
DO NOT ATTEMPT TO CLEAN OR OIL 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.
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 |
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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.
These carburetors are used on some
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 |
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Screw |
VH100, |
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Idle Adjustment |
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Screw |
VH100, |
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The Master Parts Manual or Microfiche has a direct
CHOKE LEVER
THROTTLE
LEVER
WELCH PLUG |
CARBURETOR |
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MODEL NUMBER |
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CARBURETOR DISASSEMBLY, INSPECTION AND ASSEMBLY. Carefully disassemble carburetor, removing all
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 |
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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
LONG END OF CLIP
OPEN END
OF CLIP
THROTTLE END
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FUEL BOWL |
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FLAT OF FUEL BOWL |
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TOWARD FUEL INLET |
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FITTING |
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FIBER WASHER |
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TORQUE TO |
FUEL BOWL |
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RETAINING NUT |
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50 - 60 INCH |
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POUNDS |
“O” RING |
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BRASS WASHER |
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HIGH SPEED ADJUSTMENT |
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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 |
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SEATS AT THIS |
FACE FIRST |
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POINT |
REMOVAL OF VITON SEAT |
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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 |
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EMULSION TUBE |
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DO NOT REMOVE |
WELCH PLUG |
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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 |
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WELCH PLUG TO BE |
PRY OUT PLUG |
REMOVED |
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DO NOT ALLOW |
ABOUT 1/8” (3.2 MM) |
CHISEL POINT TO |
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STRIKE CARBURETOR |
WIDE |
BODY |
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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.
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 |
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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, |
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Idle Adjustment |
HH80, 100 120 |
Screw |
VH80 100 |
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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.
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THROTTLE LEVER |
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THROTTLE SHUTTER |
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THROTTLE STOP |
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SCREW |
MOUNTING |
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INSTALL WITH |
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FLANGE |
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NUMBERS OUT |
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62 |
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29 |
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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
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THROTTLE RETURN |
CHOKE LEVER |
SPRING |
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SECONDARY |
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IDLE DISCHARGE |
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PRIMARY IDLE |
FUEL INLET |
DISCHARGE |
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THROTTLE SHUTTER |
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FUEL BOWL NUT |
FUEL BOWL |
HIGH SPEED |
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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 |
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EMULSION TUBE |
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- Replace |
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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 |
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AND AXLE |
FLOAT
SETTING
Ô Ô
ADJUSTING |
INLET NEEDLE |
TAB |
AND SEAT |
EARLY |
NEW |
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This shows early and new needle valve, seat, gasket, and spring assembly for large horsepower engine carburetors.
Early carburetors have a
.110'’
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
INSTALL WITH |
CCW |
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NUMBERS OUT |
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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
CHOKE |
CW |
SHUTTER |
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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
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MAIN |
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NOZZLE |
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FUEL |
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FLOAT |
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PASSAGE |
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SECTION 5. OVERHEAD VALVE ENGINE CARBURETORS
Overhead valve engines utilize Walbro carburetors.
THROTTLE PLATE |
CHOKE LEVER |
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THROTTLE |
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RETURN SPRING |
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IDLE SPEED |
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ADJUSTMENT |
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SCREW |
CHOKE |
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SHUTTER |
IDLE |
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ADJUSTMENT |
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SCREW |
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FUEL BOWL |
ATMOSPHERIC |
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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.
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HIGH SPEED |
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CARB. |
ADJ. SCREW* |
IDLE ADJ. SCREW* |
OH120 |
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THRU |
1 TURN* |
1 TURN* |
OH180 |
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*All Adjustments Off of Seat |
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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
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 |
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ADJUSTMENT |
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SCREW |
INSTALL WITH
NUMBERS OUT
RETAINING
SCREWS
MOUNTING |
THROTTLE |
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FLANGE |
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SHUTTER |
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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 |
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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 |
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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 |
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MAIN NOZZLE |
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NOZZLE - REUSABLE |
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(DO NOT REUSE IF REMOVED) |
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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 |
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Replace |
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 |
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CLOSEST TO CENTER |
FLOAT HINGE |
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Ô |
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AND AXLE |
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Ô |
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.275 |
(6.985 mm) |
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.315 |
(8.001 mm) |
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|
|
|
|
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
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
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
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 |
|
||
ÃœFUEL 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,
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
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
PULLEY
arope
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,
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,
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)
2.Install the
3.Install motor with two (2)
mm)screws and lockwashers. Torque screws to
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
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
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
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
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