Carburetor Identification, Troubleshooting and Service Manual 2002
Contents
1. 30 33 Primer Bulb 34 Fuel Filters P x4 DO internal Atmospheric Vent i2 e 8 459 eee eee OO Failure 36 38 Copyright 2002 by Tecumseh Power Company All rignts reserved No part of this book may be reproduced or transmitted any form or by any means electronic or mechanical including photocopying recording or by any information storage and retrievd system without permission in writing from Tecumseh Power Comp any INTRODUCTION This troubleshooting book is designed as a quick reference for carburetion problems and an aid in identifying failures and their possible causes It also directs the user to other publications and printed material that assist in properly resolving problems or making adjustments not related to carburetion but could affect carburetion Listed below are some basic DO S and DON TS to be followed when making carburetor repairs PLEASE DO Follow all instructions carefully Use new service replacement screws 650506 Torx 8 for the choke and throttle shutters screws are treated with a dry type adhesive to secure them in place Use TecumsehPower float tool 670377 or an 11 64 drill bit to set the proper float height Remove the bowl gasket and measure from the casting surface The gasket should be replaced or poor starting may result Use only genuine TecumsehPower service pa2. 8 9 SJ FE 6o d o w 5 a 5 o s jujgl m Aiea e 181414141414 fwn _ rej T Jel fel rer LLL LL EL LE LL EL LL LL ses E _ LLL fefe wina _ LE LL LL E E LL E LE fejfe Ennes _ LE LL LE LE LE bel efef oves TROUBLESHOOTING CARBURETION CONTINUED x3 iz 9 Jal L E Ole 0 lt gt 2 O 5 0 2 vo lt ier 5115 9 z W 9 sf 8 2 5 I5 O OIZ Q O o amp l o 8 q O o L z 5 2 T o D ol Z o 2 lt D Pre lololg9 E c lt o z o S E l SlWw 5 9 E Z 2 5 9 12 12 4 19 06 lt ol 2 lt s o a 5 D wl x 6 0 as 5 25 51 l S 9 Z 8 a lt D METERING SYSTEM B EE Worn Lever Set Too High 149111491 Set Too Low Not Free SPRING E Distorted LLLLLLLLULL Improperly Installed Li LL lg DIAPHRAGM Leaking Air Fuel Worn Button _ improper Assembly PLT TEE TT Ty tet IL Defective Gasket Loose Diaphragm Rivet Hole in Diaphragm SEE Loose Cover Screws BEBE INLET NEEDLE amp SEAT FHE Foreign Matter Bindi
3. Hook the wire into the air bleed hole and pull out to remove Make sure all O rings have been removed and placed on the main nozzle emulsion tube before reinstalling the tube VECTOR AND SERIES 7 EMULSION TUBE SPRING The emulsion tube spring in the Vector and Series 7 carburetor is used to put tension on the tube forcing it towards the gasket This seals the tube preventing unmetered air from entering the center leg The proper sequence is float bowl spring tube gasket and carburetor body To remove the emulsion tube gently grab the tube with a needle nose pliers and pull straight out Ifthe tube is damaged or distorted replace it HOT RESTART Occasionally on engines equipped with the dual system carburetor some rich starting conditions have occurred when the engine is warm This can be corrected using the white plastic spacer as shown and inserted in the center leg of the carburetor Service 632158 This spacer is designed to reduce the amount of prime charge in the main nozzle area for better starting under warm engine conditions It only be used on Dual System carburetors and does notlean outthe carburetor mixture DESIGNATION IDLE MIXTURE SCREW MAIN MIXTURE SCREW NOTE NOT ON SERIES 7 AND VECTOR CARBS O RING ON TO OF STEP AIR BLEED HOLE RING IN GROOVE NO RING ON SERIES 7 OR VECTOR CARBS AIR BLEED HOLES 0 RING IN GROOVE MAIN NOZZLE AIR BLEED TENSION SPRING
4. NOTE Since the mid 1980 s TecumsehPower has discontinued the practice of establishing new service carburetors TECUMSEH PRODUCTS COMPANY FILE IN Division 5 Section A ISSUED July 1975 SERVICE CARBURETORS REVISED March 2002 LIST OF PARTS REQUIRED TO BUILD A COMPLETE CARBURETOR FROM A STANDARD SERVICE CARBURETOR THIS LISTING REQUIRED ONLY WHEN ORIGINAL CARBURETOR TO BE REPLACED IS NOT AVAILABLE NOTE WELL IN ADDITION TO PARTS LISTED BELOW ALL WILL REQUIRE 1 EACH 650506 CHOKE SHUTTER SCREW 1 EACH 650417 IDLE REGULATING SCREW 1 EACH 630766 IDLE REGULATING SCREW SPRING STANDARD THROTTLE THROTTLE CHOKE CHOKE CHOKE DETENT ORIGINAL CARB SERVICE SHAFT RETURN SHAFT CHOKE RETURN DETENT SPRING PART MFG NOJ CARB NO ASSY SPRING ASSY SHUTTER SPRING SPRING SCREW 631985A 631868 630758 630757A 631985A 631868 630758 630757A 631985A 631868 630758 631985A 631615 631767 630758 631985 631615 631767 630758 632045 631985 631615 631767 630758 632045 631985 631615 631767 630758 632045 631985 631615 631767 630758 631785A 31834 631767 31837 631798 631615 631767 31837 631788A 31834 631767 631037 632045 631797 31834 631767 31837 632042 631800A 31834 631767 631037 632045 631800A 631767 631037 632045 631767 31837 631800 631767 31837 631793 631767 31837 pie 631800A 631767 631037 632045 631800A 631767 631037 632045 631792A 631767 631037 63
5. PIERCE PLUG WITHTIP PRY OUTPLUG WELCH PLUG TO BE 5 Remove the extended prime well welch plug with a P REMOVED sharpened chisel When piercing through the o ABOU extended prime well welch plug pound close to the red primer bulb side as not to mar the casting DO NOT ALLOW CHISEL POINTTO T 1 8 WIDE STRIKE 15 CARBURETOR T BODY OR CHANNEL REDUCER SMALL CHISEL 6 Clean the extended prime well w 012 tag wire carb spray 7 Remove the idle prime well welch plug Using a sharpened chisel or punch Clean the progression holes and the idle air bleed hole using tag wire and carb spray If damage occurs in progression holes replace with a new carburetor 8 Remove idle restrictor cap and clean the idle jet with tag wire and carb spray 13 CARBURETOR CLEANING SERIES 8 11 CONTINUED 9 Clean the idle circuit fuel pick up located in the center leg using tag wire 10 The Series 11 bridged carburetor has an additional idle circuit fuel pick up jet on the side of the center leg Clean this with 012 3 mm tag wire 11 Clean main jet bowl nut with tag wire Remember there are three drilled passages The fuel pick up the main jet and the idle delivery hole 12 Spray all cavities with TecumsehPower carburetor spray part 696410 14 CARBURETOR CLEANING SERIES 8 11 CONTINUED 13 Replace the welch plugs included in carb kit with a flat punch and apply fingernail polish
6. Series 6 carburetors used on TVS TVXL840 engines are similar in appearance and operation to the carburetors used on 4 cycle engines with the following differences 1 The bowl nutis left hand thread This bowl nut is identified by an L stamped on the nut and the international left thread notches across the points 2 A dampening spring is installed on the float hinge pin to reduce erratic float travel 3 two mounting bosses extend out from the carburetor body SERIES 7 CARBURETORS EMISSION The Series 7 carburetor is an emissions grade carburetor used on medium frame vertical shaft overhead valve engines It has a non metallic bowl and a snap on bowl retainer to connect it to the carburetor body This model has a fixed main jet and a fixed idle jet both are located in the carburetor bowl The float bowl float nozzle and venturi are non metallic which eliminates the corrosion and varnishing problems associated with similar metallic parts Common service areas of the carburetor are contained in the fuel bowl which include the float needle seat and main nozzle emulsion tube All of these parts can be serviced without removing the carburetor body from the engine SERIES 8 CARBURETOR EMISSION The Series 8 carburetor has both a fixed main and idle circuit The fixed idle system is achieved by a restrictor jet that meters the fuel for the idle circuit The idle restrictor jet will be capped to prevent access unles
7. 640185 166 640015 158 640008 176 640059 170 640089 181 640106 167 640188 183 640114 184 640128 184 640128 206 640209 188 640170 163 640187 190 640163 152 640011 191 640162 158 640008 202 640184 205 640186 205 640208 203 640206 206 640209 148 640181 207 640210 206 640209 HIGH ALTITUDE CARBURETOR KITS FORFIXED MAIN CARBURETORS NOTE This list applies only to products built prior to emissions regulation Engines which are identified as compliant with CARB California Air Resources Board or EPA US Environmental Protection Agency regulations can NOT be changed from theirfactory setting unless specifically authorized Engines built to O E M specifications may experience starting and operating problems when used in areas where the altitude is 4 000 feet 1220 meters above sea level or higher A leaner fuel air mixture is desirable at higher elevations to sustain good engine startability and operating characteristics Engines built with adjustable idle and main circuit carburetors can be adjusted to optimize performance The following will assist you in selecting the correct high altitude leaner jetted bowl nut for engines equipped with fixed main or dual system carburetors Order parts from your Authorized TecumsehPower Distributor or Dealer 4 CYCLE STANDARD BOWL NUT ENGINE STAMPED Over 4 000 Ft TVS90 120 ECV90 100 TNT100 64 65 75 79 103 108 126 127 137 632455 TVS90 120 OHH50 55 158 161 164 165 166 171 172 177 6327
8. RING SPRING SMALL CHISEL PIERCE PLUG WITH TIP PRY OUT PLUG WELCH PLUG TO BE REMOVED DO NOT aow T CHISEL POINT ABOUT 1 8 WIDE TO STRIKE CARBURETOR X BODY OR CHANNEL REDUCER SMALL CHISEL FLAT END PUNCH NEW WELCH PLUG SAME OR LARGER DIAMETER OF PLUG SOME INLET FITTINGS STRAINER PRESS IN PARTIALLY THEN APPLY LOCTITE 31 CARBURETOR SERVICE TIPS CONTINUED INLET FITTING REMOVAL To remove a leaking or damaged fuel inlet fitting use a 1 4 bolt 1 4 nut and 1 4 washer along with a 1 2 nut Use a pliers or vise to remove the plastic part of the inlet fitting Tap the inside of the remaining metal portion of the fitting using a 1 4 20 tap Place a 1 2 nut over the fuel fitting it may be necessary to guide one side of the nut to seat it squarely to the carburetor Next thread the 1 4 nut on the bolt until it contacts the shank add the washer and thread the bolt into the fitting until snug Tighten the 1 4 20 nut until the fitting is removed PROPER INSTALLATION OF CHOKE AND CHOKE PLATE THROTTLE PLATES ON TecumsehPower CARBURETOR Place choke plate into air horn of the carburetor Make sure the flat surface is facing down Choke plates can operate in both directions however each carburetor is designed to operate only one way Make sure it is assembled properly for your engine NOTE Always use a new screw s when reinstalling choke or throttle shutter NEVER reuse ol
9. all metal fuel inlet fitting The Walbro name is molded onto the pump cover WT WALBRO CARBURETOR The WT Walbro carburetor is used on the TC II style engine It is similar to the WTA carburetor but its reverse image The WT has no choke lever and has a combination plastic and metal fuel inlet fitting TILLOTSON HU CARBURETOR The Tillotson HU carburetor is the reverse image of the WTA Walbro carburetor It is used on the TC II The Tillotson HU has a replaceable main and Tillotson is visible on the pump cover TecumsehPower TC CARBURETOR This carburetor has a fixed idle and main which meets the emissions standards for two cycle engines The main jet is serviceable and can be accessed by removing the plastic cap The jet is removed for cleaning purposes only and must be covered after servicing to maintain compliance with emissions regulations 11 CARBURETOR CLEANING SERIES 8 11 1 Remove bowl and push the float hinge pin out with carb tool part 670377 The float cannot be rotated upward 2 Remove the seat with the carb tool 3 Remove the emulsion tube by gently inserting the carb tool Rotate the hook end until you locate the air bleed passage Then with hook in place pull the tube out 4 Remember there are two O rings on the emulsion tube You may have to go into the center leg a second time to remove the upper second O ring 12 CARBURETOR CLEANING SERIES 8 11 CONTINUED
10. or hesitates while engaging the load lean turn the main mixture adjusting screw out counterclockwise 1 8 turn at a time testing each setting with the equipment under load until this condition is corrected If the engine smokes excessively rich turn the main adjusting screw in clockwise 1 8 turn at a time testing each setting with the equipment under load until this condition is corrected After the main mixture is set move the speed control to the IDLE or SLOW position If the engine does not idle smoothly turn the idle mixture screw 1 8 turn either in clockwise or out counterclockwise until engine idles smoothly Recheck your HIGH and LOW RPM settings and adjust as necessary PRE SETS ANDADJUSTMENTS CONTINUED RPM ADJUSTMENTS Now the LOW and HIGH speed screws can be adjusted to the recommended RPM s First identify the location of both HIGH and LOW speed RPM adjustment screws then identify the recommended HIGH and LOW RPM settings according to microfiche card 30 the computer parts look up system or Service Bulletin 107 for rotary mowers GOVERNED NON GOVERNED IDLE With the engine running atthe lowest speed set the governed idle atthe designated RPM by bending the idle RPM tab Next set the non governed idle by pushing the bottom of the governor lever away from the control brackets so the throttle lever contacts the idle speed screw Hold the lever in this position and turn the idle adjustment screw clockwis
11. release startertension to prevent the engine from reversing due to compression pressure 2 Remove the spark plug squirt 1 2 ounce 15 ml of clean engine oil into the spark plug hole 3 Coverthe spark plug hole with a shop towel and crank the engine over slowly several times 4 Replace the spark plug and tighten Pull the starter handle as performed in step 1 The piston position blocks the cylinder ports on 2 cycle engines or closes the valves on 4 cycle engines preventing air from entering and oil from leaving the cylinder bore during storage 5 Re connectthe spark plug wire on the spark plug HIGH ALTITUDE JET FOREMISSIONIZED CARBURETORS The following list of altitude compensation jets is being provided for use with emission grade carburetors at elevations between 6 000 and 11 000 feet 1 824 3 344 meters This list applies only to engines which are identified as compliant with CARB California Air Resource Board or EPA US Environmental Protection Agency regulations To determine the proper jet for your carburetor simply locate the number stamped into the original bowl nut Then use the chart below to identify and install the proper jet NOTE Installation of altitude compensation jets is NOT WARRANTY STANDARD JET SERVICE HIGH ALT JET SERVICE NUMBER NUMBER USE BETWEEN 6 000 TO 11 000 FT NUMBER 1 824 TO 3 455 M 148 640181 203 640206 152 640011 183 640114 157 640032 169 640087 158 640008 175 640062 162 640024 149
12. serviceable main nozzle emulsion tube FIXED MAIN mew HOW TO IDENTIFY TecumsehPower CARBUREIOQOR CONTINUED To determine whether the carburetor is a Series 3 or Series 4 look at the throttle or choke end of the carburetor Series 3 will have one screw on the throttle and choke plates The Series 4 will have two screws on the throttle and choke plates SERIES 3 SERIES 4 VECTOR CARBURETORS The Vector carburetor is a float feed nonadjustable carburetor with a one piece extruded aluminum body The float bowl float nozzle and venturi are nonmetallic which eliminates the corrosion and varnishing problems associated with similar metallic parts Common service areas of the carburetor are contained in the fuel bowl which include the float needle seat and main nozzle emulsion tube All of these parts can be serviced without removing the carburetor body from the engine NOTE If the unit was run with poor filter maintenance the venturi should be removed and the air bleeds cleaned with solvent SERIES 6 CARBURETORS 4CYCLE Series 6 carburetors are used on 2 and 4 cycle engines They have a larger venturi than the dual system carburetor and use a simple fixed idle system Series 6 carburetors used on both vertical and horizontal applications are nonadjustable The 4 cycle version pictured has a stepped primer bulb HOW TO IDENTIFY TecumsehPower CARBUREIQR CONTINUED SERIES 6 CARBURETORS 2 CYCLE
13. the fuel inlet is adjustable and attached to the carburetor body with a banjo bolt This carburetor is used on some TVS rotary lawnmower engines WALBRO LMK CARBURETOR The Walbro LMK has a large venturi and a fixed main with an adjustable idle It is used on some OHV engines This carburetor has a noncorrosive float and a viton tipped needle It also has a nonmetallic choke shaft It is easily identified by the Walbro name on the carburetor body next to the idle adjustment screw WALBRO WHG CARBURETOR The WHG used on castiron engines can be builtas a fully adjustable single adjust or nonadjustable carburetor It has a large venturi Its most recognizable feature is the large square mounting surface on the choke end ofthe carburetor DIAPHRAGM CARBURETORS DIAPHRAGM CARBURETORS The diaphragm carburetors are unique These carburetors can be operated at a more severe angle than float style carburetors They still require that the fuel supply be located in a position that allows it to be gravity fed Its most distinctive feature is the lack of a fuel bowl 10 DIAPHRAGM CARBURETORS CONTINUED WTAWALBRO CARBURETOR The WTA carburetor has a rubber type diaphragm which is exposed to intake pressure on one side and to atmospheric pressure on the other The WTA is used on TC200 and 300 engines There are two adjustment screws They are the idle mixture screw and the idle RPM screw The WTA has a choke and an
14. toward the air intake choke end of the carburetor INSTALLING THE FLOAT BOWL Install the float bowl by placing the detent portion opposite of the hinge pin Make sure the deepest end of the bowl is opposite of the inlet needle The bowl has a small dimple located in the deepest part The purpose of this dimple is to minimize the chances of the float sticking to the bottom of the bowl caused by stale fuel 30 CARBURETOR SERVICE TIPS CONTINUED FLOAT BOWL SERVICE VECTOR AND SERIES 7 To remove the float take a needle nose pliers and grasp the cross piece between the center leg and the pivot point on the float It is critical to pull the float straight out so as not to break it To install the float place the float hinge pin into the hinge slot on the float and press into place in the bowl Some bowls may also contain a clip or retaining ring used to hold the seat in place This is pre installed as needed in the manufacturing process To make assembly easy an alignment notch has been placed on the gasket and the bowl to guarantee proper location of the gasket ASSEMBLY OF MAIN MIXTURE SCREW When reassembling the main mixture adjusting screw position the coil spring on the screw first followed by the small brass washer then the rubber O ring seal REMOVALAND INSTALLATION OF WELCH PLUGS To perform a proper cleaning all welch plugs should be removed to expose drilled passages To remove the welch plug shar
15. use compressed air or a soft tag wire to clean passages 2 fparts are worn or damaged determine the extent of the damage Check to see if the repair be made by just replacing parts or if the body of the carburetor is worn and in need of replacement 3 Always replace throttle and choke shutter screws with new service screws 650506 New service screws have a dry adhesive on the threads Replace all gaskets IDLE SPEED ADJUSTMENT SCREW CHOKE SHAFT AND LEVER THROTTLE SHAFT ANDLEVER CHOKE SHUTTER DETENT REFERENCE MARK ON THROTTLE SHUTTER THROTTLE SHAFT RETURN SPRING INLET THROTTLE n er FITTING MAIN NOZZLE SHUTTER SCREEN INTERMEDIATE 1229 FITTING IDLE AND 17 cm INLET 299 a a ee F3 AIR BLEED EA 77 Jc m INLET SEAT ORIFICE me Med Esos nr umet GASKET uS fara DIAPHRAGM ANN 22 IDLE MIXTURE Bes ADJUSTMENT pee eed GAKSET SCREW NEAL RING INLET NEEDLE If Present SEAT AND MAIN MIXTURE ADJUSTMENT SPRING SCREW AND RING ASSEMBLY If Present DIAPHRAGM aa i WES WELCH PLUG If Present ATMOSPHERIC VENT HOLE MAIN NOZZLE CHECK BALL If Present NON METALLIC ITEMS CAN BE DAMAGED BY HARSH CARBURETOR CLEANERS SECONDARY IDLE MIXING WELL IDLE DISCHARGE AIR BLEED NOT OPERATING MAIN NOZZLE
16. 2045 631792A 631767 631037 632045 631793 631767 31837 631793 631767 31837 631793 631767 31837 630757A 631793 631767 31837 630757A 631792A 631767 631037 632045 631792A 631767 631037 632045 631793 631767 31837 632042 631800A 631767 31837 632042 631795A 631767 31837 632042 631793 631767 31837 632000A 631767 630736 631476 631790A 631767 OBSOLETE 31837 631794 631767 OBSOLETE 31837 631795A 631767 See Note 1 31837 632042 631795A 631767 See Note 1 31837 632042 631792A 631767 OBSOLETE 631037 631792A 631767 OBSOLETE 631037 631794A 631767 631538 31837 631792A 631767 630973 631037 632045 631792A 631767 630973 631037 632045 631993 OBSOLETE OBSOLETE OBSOLETE 630736 632000A 631255 631767 631605 630736 631798A 631615 631767 OBSOLETE 31837 631993 OBSOLETE OBSOLETE OBSOLETE 31837 631993 631868 OBSOLETE 631869 31837 631795A 631615 631767 OBSOLETE 31837 632042 631795A 631615 631767 OBSOLETE 31837 632042 LIST OF PARTS REQUIRED TO BUILD A COMPLETE CARBURETOR FROM ASTANDARD SERVICE CARBURETOR THIS LISTING REQUIRED ONLY WHEN ORIGINAL CARBURETOR TO BE REPLACED IS NOT AVAILABLE NOTE WELL IN ADDITION TO PARTS LISTED BELOW ALL WILL REQUIRE 1 EACH 650506 CHOKE SHUTTER SCREW 1 EACH 650417 IDLE REGULATING SCREW 1 EACH 630766 IDLE REGULATING SCREW SPRING STANDARD THROTTLE THROTTLE CHOKE CHOKE DETENT RETURN SPRING SHUTTER SPRING SPRING SCREW CRF 3E N
17. 37 TVS90 120 OVRM40 60 124 125 133 135 136 631026 OVM amp OVXL120 OHV11 13 Formula 120 141 632239 Dellorto 69 633017 VLVAO 50 55 60 Jet 632648 VLVAO 50 55 60 Nozzle 632638 TVM170 195 83 132 632239 TVM220 109 131 631973 OHV15 Walbro LMK26 Jet 632688 2 CYCLE AH AV520 amp 600 5 600 101 632368 TVS TVXL840 L118 L119 632463 HSK840 845 850 HXL840 124 125 631026 TC200 TC300 Tillotson carburetor only Jet 632940 TC200 TC300 Tillotson HU112 and HU114 Jet N A Do notinstall leaner jetted bowl nuts on engines used below four thousand feet as starting and operating problems will occur DOING SO WILL VOID THE ENGINE WARRANTY THROTTLE CONTROL BRACKETS GOVERNORS AND RPM ADJUSTMENTS Before adjusting any mixture screws reset the screws to the recommended carburetor presets Check for proper governor adjustments as outlined in the appropriate Technician s Handbook Identify the locations of your high speed and low speed RPM adjustment screws Check to make sure that the throttle control brackets are adjusted properly to allow for full choke Always make sure that normal maintenance procedures ie oil fuel air cleaner etc have been checked Consult microfiche card 30 the computer parts look up system or Service Bulletin 107 for C P S C specifications to determine the proper RPM settings Start the engine allow it to warm up the carburetor can then be adjusted for optimum performance by using the information outlined in
18. 893 USE 631855 USE 631226 USE 631226A USE 631564 USE 630978 CHECK VALVE FUEL FITTING USE 630898 USE 630932A USE 631893 USE 631790 USE 631790 631785A 631786 631787 631788 4 631788A 631789 4 631789A 631790 4 631791 631792 4 631792 631793 631794 4 631794 631795 4 631795 SVC CARB NF SERVICE CARB SERVICE CARB USE 631788A SVC CARB NF USE 631789 SVC CARB NF USE 631790 631790A SVC CARB NF SERVICE CARB USE 631972A SVC CARB NF SERVICE CARB USE 631794 SVC CARB NF USE 631795 SVC CARB NF 2f SERVICE CARBURETOR INFORMATION CONTINUED When the price list supersedes the original carburetor you are ordering to a service carburetor you will need to identify the parts not included on the service carburetor To determine these parts turn to Division 5 Section A in the Master Parts Manual or the appropriate microfiche card listed under carburetor The information can be found under the title List of parts required to build a complete carburetor from a standard service carburetor The cross section shown below uses 631211 as the original carburetor number The price list supersedes that number to 631790A which is a service carburetor The items shown following the number must be added to the service carburetor to make it a complete carburetor Parts may be used from the original carburetor if they are in good condition NEVER REUSE THE ORIGINAL THROTTLE AND CHOKE SHUTTER SCREWS
19. AIR BLEED SERIES 7 MIXING WELL ATMOSPHERIC DE 1 27 VENT PASSAGES AIR BLEED MAIN NOZZLE IDLE TRANSFER AIR BLEED PASSAGE SERIES 8 MIXING WELL IDLE AIR BLEED IDLE i MAIN NOZZLE METERING AIR BLEED JET E IDLE TRANSFER FUEL PASSAGE SERIES 9 ATMOSPHERIC IDLE TRANSFER FUEL PASSAGE IDLE MAIN NOZZLE AIR BLEED AIR BLEED IDLE FUEL PASSAGE TROUBLESHOOTING CARBURETION START Hard Starting ADJUSTMENTS Low High FUEL SYSTEM Plugged Tank Filter or Vent Restricted Fuel Line Dirt in Fuel Passage Loose Damaged Fuel Line Leak in Pulse System Restricted Pulse Channel Loose Pump Cover Screw Defective Pump Diaphragm AIR SYSTEM Plugged Air Filter Defective Manifold Gasket Loose Carb Mounting Bolts Worn Throttle Shaft or Valve Incorrect Throttle Assembly Loose Throttle Valve Screw Throttle Shaft Too Tight Bent Throttle Linkage Defective Throttle Spring Bent Throttle Stop Lever Choke Not Functioning Properly Worn Choke Shaft or Valve 24 c E Cc O 72 9 2 E 8 lt O O c 5 a EJ 9 c gt S LL LL O 7 9 o c o0 z 2 T 2 Q UO o S o o J O LU Z O J L U 5 9 18 IX L g E lt S L z 5 2 2
20. E IE 3E I ERES 631178 134 631789 631615 631767 31842 31837 169 630973 631037 631767 31869 31837 631767 31859 31387 631767 31868 31837 631767 630973 631037 632045 USING THE COMPUTER PARTS LOOK UP SYSTEM Computer parts look up systems are fast efficient and allow you to use several different options when looking up parts If you know the part or manufacturing number of the carburetor you can use that number to access information to provide you with a parts list artwork availability and pricing One method of obtaining the carburetor part number requires you to know the engine model number This is not always available and could cause your customer some inconvenience having to return home to retrieve that information from the engine If the customer has the carburetor along you simply need to locate the manufacturing number on the carburetor and enter that number into the look up system The following steps will direct you through the CARBURETOR procedures needed to use either parts look up system MANUFACTURING DATE CODE NUMBER ALTERNATE LOCATION FOR MANUFACTURING PartSmart In this system the carburetor manufacturing number is considered an assembly All assemblies are considered models and can be found under the Model Inquiry selection on the main menu Click on the Model Inquiry Icon Type the manufacturing number in the name box This will automatically scroll the information on the screen Click
21. LY VENTED INTERNALLY VENTED EXTERNALLY VENTED SEALING SURFACE FUEL FILTERS TecumsehPower engines use some form of filtration prior to the carburetor When a non TecumsehPower tank is used an in line fuel filter between the tank and carburetor is required The filters use a 75 micron fibrous paper to trap even the smallest particles of dirt while maintaining the same flow rate An arrow showing the direction of flow is molded into the body of the filter to aid in installation FUEL TANK FILTERS All fuel tanks provided by TecumsehPower have a 75 micron stainless steel filter screen molded right into the tank over the fuel outlet On TC series engines a fuel filter is located on the fuel line in the tank These filters can become restricted when foreign debris enters the tank or when varnish and gum deposits form due to stale fuel Be sure to check these areas if you have a fuel flow problem INTERNAL ATMOSPHERIC VENT PASSAGE INTERNAL ATMOSPHERIC VENT PASSAGE FLOAT STYLE CARBURETOR Some internally vented float style carburetors will use a tygon tube within the air cleaner This tube must be present for the carburetor to operate properly D a TYGON TUBE LOCATION TYGON TUBE 35 FAILURE ANALYSIS DAMAGED IDLE OR MAIN MIXTURE ADJUSTING NEEDLES Mixture adjusting needles have a critical taper on the end that is easily damaged from overtightening or abuse Ch
22. NUED WALBRO CARBURETORS 2 CYCLE PRE SETS AND ADJUSTMENTS Idle Pre se 1 1 4 turns WTA amp WT TILLOTSON CARBURETOR 2 CYCLE PRE SETS AND ADJUSTMENTS Carburetor Model No Main Pre set Idle Pre set HU ANE M 1 1 2 turns IDLE PRE SET Turn idle mixture adjustment screw clockwise finger tight to closed position then turn the screw counterclockwise according to the above chart This setting will allow engine to be started so carburetor can be fine tuned FINALADJUSTMENT Idle Mixture Start the engine and let it reach its normal operating temperature 3 5 minutes Begin slowly turning the idle mixture screw in clockwise As you turn itin clockwise the engine will begin to falter this is the lean drop off point NOTE If the RPM is greater than 2 400 stop the procedure and reduce idle RPM Settings above 2 400 will cause fuel from the main jet to contribute to the idle mixture creating an inaccurate idle mixture setting Turn the needle out until the engine begins to falter Note this position this is the rich drop off Your final needle setting is halfway between the rich and the lean drop off points Once the mixture is set the idle speed needs to be adjusted Set the idle speed atthe recommended RPM WALBRO CARBURETORS 4 CYCLE FIXED WHG OH120 180 On occasions high altitude has affected the operation of high and low speed performance To correct this situation use the following steps 1 Removeair
23. ON Litt TTT Ty Ty Ey wem Over ric HeSitates O Ring Mission or Damaged Emulsion Tube 21 TROUBLESHOOTING CARBURETION TecumsehPower CARBURETORS FLOAT AND DIAPHRAGM eedle Closed lean RATE accelerate _ LL icc Erratic idle Idle e Hunts at high Speed R uns with needle Control Engine Overspeeds Hard Starting Fuel Leak at Carburetor Engine Floods AIR SYSTEM Plugged Air Filter Leaky Carburetor Gaskets wee 2144 wino e Riera Throttle or Choke Shafts Worn Choke not functioning properly Plugged Atmospheric Vent Air Bleed Restricted Damaged or Leaky O Ring DIAPHRAGM SYSTEM Damaged Diaphragm Stuck or Dirty Ball Check Diaphragm Upside Down _ ts with n 21111441144 tet Lt Ut nor _ e tet idees fas ves dde START i tT tT tT 22 TROUBLESHOOTING TecumsehPower CARBURETORS Use the troubleshooting chart to determine the cause of a particular carburetor problem Once the problem is identified it will be necessary to select the proper corrective action Most repairs will consist of one of the following items 1 At times it will be necessary to thoroughly clean the carburetor First remove all welch plugs adjustment screws O rings and the needle and seat After soaking the carburetor in a commercial cleaner for no longer than 30 minutes
24. SN a NN PANS wi M es M PLASTIC SPACER PRIMER BULB SERVICE PRIMER BULB IDENTIFICATION Care must be used when replacing carburetor primer bulbs Using the wrong primer bulb could cause hard starting or non starting problems Currently TecumsehPower uses four different carburetor mounted primer bulbs To avoid problems use the Master Parts Manualforthe correct application The five primer bulbs currently used feature two different shapes derby and stepped or hourglass and two different venting types internal or external STEPPED PRIMER BULBS A stepped primer bulb is used to force a charge of air into the bowl through the atmospheric vent chamber The sealing surface as pictured prevents air from going back into the air filter NOTE Bowl prime systems require a good gasket seal on the bowl ora low prime charge will be generated To avoid serious eye injury wear safety glasses or goggles when removing retainer To remove the primer bulb grasp the bulb with a pliers pulling and twisting it out of its body After removing the primer bulb the retaining ring must be removed Use a screwdriver to carefully pry the retainer out of the body Do notreuse old primer bulb or retainer After the primer bulb is removed clean the primer passages thoroughly Press the new bulb and retainer into position using a deep reach socket NOTE New primer bulbs come with a new retaining ring 34 INTERNAL
25. TEGUNISEN POWER Service Dealer s and Technician s Training and Informational Series Carburetor Identification Troubleshooting and Service Fe ENGINES s TRANSMISSIONS Table of Contents 1 Engine 0 1 Fuel 2 Storage 22 High Altitude jet buio 3 High Altitude Carburetor Kits for Fixed Main 22 4 Throttle Control Brackets Governors and RPM Adjustments 5 How to Identify TecumsehPower Carburetor 95 10 Non TecumsehPower Carburetors 10 Diaphragm 10 11 Carburetor Clearing Series 8 41 29 eRe ee eee eee eae 12 16 Emission Carburetors eee eee ene 7 Pre Sets and Adjustments Non Emission 2 wc ex owe owe a 18 20 Troubleshooting Carburetion Chart 21 22 Troubleshooting TecumsehPower Carburetors 28 Troubleshooting Carburetion TC Series 24 25 Troubleshooting Walbro and Tillotson 26 Metering System Service 2222 27 28 Using the Computer Parts Look Up uten 29 Float Adjustment 29 Carburetor Service
26. cleaner assembly 2 Remove choke shaft assembly 3 Using an ice pick type tool with a small hook on the end remove the brass cup plug out of the nozzle well vent NOTE Do not use a thread tap as chips may enter the carburetor 4 Reassemble choke shaft assembly 5 Reinstall air cleaner assembly 20 IDLE SPEED 7 IDLE MIXTURE ADJUST SCREW TILLOTSON HU CARBURETOR IDLE SPEED pr IDLE MIXTURE ADJUST SCREW WALBRO WT CARBURETOR IDLE AIR RESTRICTOR TROUBLESHOOTING CARBURETION TecumsehPower CARBURETORS FLOAT AND DIAPHRAGM ntro 9 9 2 oloja 3 ol o tg 9 d 2 5 9 5 15 21 9 wo 10 910 _ ore Em Elm ow gt I uil D gt 42 2 5 _1 Q gt o elt a 2 2 3 515153145 5 r i w 5 1 aM START p EN lie Rich tate des with fel Hunts 212414110 Will not FUEL SYSTEM Improper Priming Procedure Bad Bowl Gasket Plugged Tank Filter or Vent Fuel Pick up Restricted per 1 prr Idle Port Restricted Damaged Adjustment Needles Ri Incorrect Float Height Mb eee Main Nozzle Restricted 2 41 EN MEN Dirty Stuck Needle and Seat EHSHHRHREFEHHRHSHIE EMISSI
27. d false starts inherent to emissions engines However external identification of the Series 11 carburetor has been a challenge To make this ID simple the Series 11 carburetor idle restrictor cap will be black and all others will be gray The part number for the black cap is 640200 and the gray is 640053 SERIES 11 BRIDGED This carburetor is identical to the Series 11 with the exception of the center leg Anon metallic jet is pressed into the center leg to allow additional fuel into the main jet for applications that require this fuel to enhance run performance CARBURETOR CLEANING SERIES 11 and SERIES 11 BRIDGED With the additional fuel well welch plug removed you can see the small plastic metering jet which can be distorted if left to soak in a carb dip tank Currently this metering jet is not a serviceable part Our position has been to soak a carburetor no more than 75 hour but the exception is the Series 11 carburetor To be safe service all TecumsehPower carburetors with Carburetor Spray 696410 along with a 012 304 mm gauge wire CAPPED JET NONMETALLIC JET BRIDGED STANDARD 11 SERIES 11 NON TecumsehPower CARBURETQRS LLL DELLORTO CARBURETOR The Dellorto carburetor is similar to the dual system carburetor It has no adjustments and has a primer assist start It has a noncorrosive float and the needle is viton tipped eliminating the viton seat found in the dual system carburetor The angle of
28. d screw s THROTTLE THROTTLE PLATE SERVICE When installing the throttle plate on the 2 7 hp carburetor position the plate with scribe mark facing out and in the 12 o clock position NOTE Make sure with all carburetors that binding does not When installing the throttle plate on the 8 17 hp carburetor position the plate with scribe mark facing out and in the 3 o clock position NOTE Make sure with all carburetors that binding does not Occur 32 CARBURETOR SERVICE TIPS CONTINUED DIAPHRAGM CARBURETOR DESIGNATION If the carburetor has an F designation on the casting it will identify the installation sequence of the gasket and diaphragm on the carburetor F designated carburetors have the diaphragm installed first then the gasket then the cover If there is no designation the sequence is then gasket diaphragm and cover SERVICEABLE EMULSION TUBES Some carburetors use a serviceable emulsion tube sealed with O rings on one or both ends When servicing these carburetors the O ring s on the emulsion tube needs to be removed During the removal of the tube the O ring on the venturi end of the tube may remain stuck in the center leg of the carburetor This O ring must be removed and replaced to guarantee proper sealing and operation To remove the tube bend a 90 hook in a paper clip or stiff wire Reach in the venturi and push the main nozzle emulsion tube out as far as possible
29. dentify the location of both HIGH and LOW speed governor adjustment screws then identify the recommended HIGH and LOW RPM settings according to microfiche card 30 If further adjustment is required the main adjustment should be made under a load condition Never operate the engine with covers or guards removed Rotating parts can cause severe injury Keep hands feet hair jewelry and clothing away from all moving parts Engage the driven equipment cutter deck impeller etc so asto putthe engine under a loaded condition IDLE MIXTURE SCREW MAIN MIXTURE CARBURETOR MODEL NUMBER IDLE MIXTURE SCREW FIXED MAIN IDLE MIXTURE SCREW MAIN MIXTURE SCREW If the engine stops or hesitates while engaging the load lean turn the main mixture adjusting screw out counterclockwise 1 8 turn at a time testing each setting with the equipment under load until this condition is corrected If the engine smokes excessively rich turn the main adjusting screws in clockwise 1 8 turn at a time testing each setting with the equipment under load until this condition is corrected After the main mixture is set move speed control to the IDLE or SLOW position If the engine does not idle smoothly turn the idle mixture screw 1 8 turn either in clockwise or out counterclockwise until engine idles smoothly Recheck your HIGH and LOW RPM settings and adjust as necessary 19 PRE SETS AND ADJUSTMENTS CONTI
30. e to increase or counterclockwise to decrease engine idle speed The setting on the carburetor screw should be set 600 RPM below the tab or governed idle setting WALBRO CARBURETORS 4 CYCLE PRE SETS AND ADJUSTMENTS Carburetor Model No Main Pre set Idle Pre set LMH 1 1 2turn 1 1 2turn WHG amp LME 1 1 4 turn 1 1 4 turn LMK FIXED MAIN AND IDLE PRE SETS Turn both the main and idle mixture adjusting screws in clockwise finger tight CAUTION Over tightening will damage the tapered portion of the needle Now back the screws out counterclockwise to the pre set figure in the chart shown above NOTE Some carburetors have fixed main jets The absence of the adjusting screw indicates a fixed jet and no adjustment is necessary FINALADJUSTMENTS Start the engine and allow it to warm up to normal operating temperature 3 5 minutes Set the speed control to HIGH or FAST position then turn the main mixture adjustment screw in clockwise slowly until the engine begins to run erratic lean Note the position of the screw Now turn the screw out counterclockwise until the engine begins to run erratic rich Turn the screw in clockwise midway between these two positions This will be the best setting Set the speed control to IDLE or SLOW position and adjust idle mixture screw in the same manner as the main mixture screw Now the LOW and HIGH speed governor adjustment screws can be set to the recommended RPM s First i
31. eck these parts if your carburetor is difficult to adjust WATER CONTAMINATION Water contamination in the fuel system causes oxidation and rust on the component parts Once the oxidation process starts it is irreversible the carburetor must be replaced GUM AND VARNISH When the fuel is not completely drained from the system during prolonged storage the most volatile parts of the fuel begin to oxidize and evaporate This leaves the crude portion of the fuel to remain and forms into resin gum and varnish which will restrict and clog the fuel 36 system s passages FAILURE ANALYSIS CONTINUED WORN THROTTLE AND CHOKE SHAFTS When operating in a dirty or sandy environment these areas can wear rapidly causing erratic performance Some shafts have been plated and dust shields have been added to retard this wear This is done based on the application needs Keeping these areas free from dirt and grit will extend the life ofthe carburetor CRUSHED FLOAT A crushed float will sink to the bottom of the carburetor bowl holding the inlet valve open and causing the engine to flood This condition is caused either from water in the fuel bowl freezing during extreme cold temperatures or by blowing compressed air directly into the fuel inlet while the carburetor is assembled WORN HINGE PIN The hinge or hinge pin can wear excessively from dirt or foreign matter in the fuel system These worn areas will cause a sticky or bindi
32. eedle for the idle The long needle is used on air adjust systems The short needle on fuel adjust systems The adjustments are the same for both systems however the drop off point may not be as noticeable FINALADJUSTMENTS MAIN Start the engine and allow it to warm up to normal operating temperature 3 5 minutes Set the speed control to HIGH or FAST position then turn the main mixture adjustment screw in clockwise slowly until the engine begins to run erratic Note the position of the screw Now turn the screw out counterclockwise until the engine begins to run erratic Turn the screw in clockwise midway between these two positions This will be the best setting Set the speed control to the IDLE or SLOW position check for proper IDLE or LOW speed RPM and adjust the idle mixture screw in the same manner as the main mixture screw If further adjustment is required the main adjustment should be made with the engine under a loaded condition 18 SERIES 1 IDLE MIXTURE MAIN MIXTURE SERIES III IV IDLE MIXTURE MAIN MIXTURE SCREW DIAPHRAGM DESIGNATION IDLE MIXTURE SCREW MAIN MIXTURE SCREW Never operate the engine with covers or guards removed Rotating parts can cause severe injury Keep hands feet hair jewelry and clothing away from all moving parts Engage the driven equipment cutter deck impeller etc so as to put the engine under a load condition If the engine stops
33. emulsion tube This tube is sealed on both ends using O rings or a gasket These components are critical to the emission grade engine in obtaining repeatable emissions certification The gasket used on the Series 7 and Vector carburetors acts as a seal and is used instead of an O ring Z ATMOSPHERIC X VENT PASSAGES MAIN NOZZLE AIR BLEED IDLE FUEL TRANSFER PASSAGE RING MAIN JET wu U SPRING DRILLED BOWL NUT IDLE RESTRICTOR COINED EDGE FINE BLANK EDGE NOT USED ON SERIES 7 or VECTOR CARBS RING ON TOP OF STEP IN GROOVE 0 RING IN GROOVE O RING 17 PRE SETS AND ADJUSTMENTS NON EMISSION TecumsehPower CARBURETORS Pre sets and Adjustments Engine Model Main Pre set Idle Pre set All models with float type carburetors All models with diaphragm type carburetors 1 1 2turn 1 turn 1 turn 1 turn MAIN AND IDLE PRE SETS Turn both main and idle mixture adjusting screws in clockwise finger tight CAUTION Over tightening will damage the taper portion of the needle Then back the screws out counterclockwise to the pre set figure in the chart shown above NOTE Some carburetors have fixed main jets The absence of the adjusting screw indicates a fixed jet and no adjustment is necessary FUEL ADJUST AIR ADJUST NOTE Series carburetors are built with one of two different styles of adjustment n
34. ing to service number cross reference list Find the service part number listed for the carburetor It will also list the page or grid where the carburetor breakdown can be found When referencing the carburetor in the price list the original carburetor may be superseded to a service carburetor Some TecumsehPower service carburetors will not have the fuel fitting These carburetors can be identified by the description listed as SVC Carb NF meaning service carburetor no fitting If this designation is not made in the listing the carburetor will have a fuel fitting Std MANU FACTURING NUMBER DATE CODE MFG TO SERVICE NO Mfg Model No Service Part No Page Mfg Model No Service Part No 154 155 156 157 Pkg Part Qty Number 631176 631195 631182 631181 631185 631217 631186 631213 631211 631210 631196 631244 631244 631209 631241 631928 631215 631218 Code Description or S upersedence 215 216 217 220 221 222 223 224 225 226 221 229 229 230 251 232 233 234 Pkg Part Qty Number 631375 631286 631301 631297 631297 631299 631312 631290 631294 631298 631295 631311 631310 631310 631341 631349 631316 631313 Std Code Description or Supersedence 10 10 631183 631184 631190 631191 631193 631194 631197 631198 631201 631202 631205 631207 631208 631211 4 WASHER WASHER 0 RING WASHER USE 631
35. ng Worn Needle Body or Tip dej fetes Fo py ptt dey tee dtr pede ted d NOZZLE CHECK VALVE S S Si BEE LL aM EINEN LE LL LL ees HHE _ Tot LL eee LL LLL frer TROUBLESHOOTING WALBRO WTA WT AND TILLOTSON HU DIAPHRAGM PUMP CARBURETORS The Walbro and Tillotson diaphragm pump carburetors operate similarly by using a diaphragm impulse fuel pump and a diaphragm needle metering system The most common problems associated with these carburetors will be found in these two areas Fuel Pump The fuel pump is normally trouble free but some problems that may arise are 1 The diaphragm check valve can become stuck in place by fuel deposits such as gum and varnish This would stop the flow of fuel through the carburetor 2 The ribs on the face of the cover can become damaged through misuse and will allow the pump to leak 3 The smooth machined surface where the check valves seat can get scratched or nicked again causing the pump to leak METERING SYSTEM The metering system is made up of four main parts Metering Diaphragm Metering Lever Metering Spring Metering Needle PERS Some ofthe problems that could occur in this system are 1 The diaphragm is damaged or torn resulting in a failure to allow fuel to flow from the pump to the metering side of the carburetor 2 he diaphragm gets hard or stiff from stale fuel sl
36. ng a 640 000 and higher series number Engine parts that are emissions certified will carry a 40 000 and higher series number The fuel metering jets are fixed on both the idle and high speed circuit The bowl nut on the Series 1 3 4 8 9 10 and 11 and 11 Bridged are drilled from the bottom and plugged for the main The Vector and the Series 7 carburetors use a non metallic jet held in place by the bowl drain screw to meter fuel for the main NOTE The Series 9 carburetor becomes emission compliant when used on a fixed speed rotary mower application The idle on the Series 8 is metered using a threaded restrictor See illustration Proper torque of this screw is critical and should be torqued to 5 8 lbs or 5 to 1 nm If it is not it may vibrate loose When the restrictor is placed in the idle circuit passage it is capped with a tamper resistant plastic cap Tampering is considered the rejetting or modification through resizing of the jet If the jet is removed for cleaning it must be recapped to prevent tampering when it is re installed On the Vector and Series 7 a small brass jet in the center leg idle passage in the bowl is used to meter fuel for the idle The throttle shutter will have a coined edge or a fine blank edge for improved sealing capabilities The scribe mark must always face out The position of the mark is determined by engine size page 31 Emissions carburetors will have a serviceable plastic main nozzle
37. ng float which will result in either a flooded or starved engine FAILURE ANALYSIS CONTINUED WORN NEEDLE AND SEAT This is another area that can wear rapidly from dirt or foreign matter in the fuel system This condition creates a poor seal at the seat area causing the carburetor to flood or the engine to run rich This can also cause the needle to stick in the seat which will stop the flow of fuel WORN CARBURETOR BODY If throttle shafts are plated operation in a dirty or sandy environment will tend to cause wear to the carburetor body in the shaft area Excessive wear in this area will cause erratic engine performance or a binding throttle plate Again to avoid this situation clean these areas regularly and keep them free from dirt and grit 38 TecumsehPower ENGINES amp TRANSMISSIONS TecumsehPower International LTD TecumsehPower Company 152 154 Commercial Road ds d Staines Middlesex et 2 United Kingdom TW18 2 one 262 377 2700 Phone 44 1 784 450785 FAX 262 377 4485 Fax 1 784 453563 wwwW TecumsehPower com Tecumseh Carburetor Parts Tecumseh Carburetors Form No 695907 12 07 Litho in U S A
38. nnecting the spark plug lead and ground it to prevent start up Next turn the engine over by hand A definite resistance should be noticed on the compression stroke Using a cylinderleak down tester is also possible After these basic checks have been performed and you are satisfied with the engine s condition attempt to start it If it does not start remove the spark plug and check its condition If it is dry you can assume there is a problem with the carburetor or the fuel system Continue by troubleshooting the carburetor FUEL RECOMMENDATIONS FUEL TecumsehPower strongly recommends the use of fresh clean unleaded regular gasoline in all engines Unleaded gasoline burns cleaner extends engine life and promotes better starting by reducing build up of combustion chamber deposits Reformulated fuels containing no more than 10 Ethanol 15 MTBE 15 ETBE or premium gasoline can be used if unleaded regular gasoline is not available Leaded fuel may be used in countries where unleaded fuel is not available NEVER USE FUEL CONTAINING METHANOL STORAGE IF THEENGINE IS TO BEUNUSED FOR 30 DAYS ORMORE Gasoline Fuel vapors are highly flammable and can explode Fuel vapors can spread and be ignited by a spark or flame many feet away from the engine To prevent injury or death from fuel fires follow these instructions e Never store the engine with fuel in the fuel tank inside a building with potential sources of ignition such as hot water and
39. on the bar listing the information you have selected to view artwork and a parts list FLOAT ADJUSTMENT PROCEDURE FLOAT HEIGHT SETTINGS TOOL 670377 Proper float setting will require the use of TecumsehPower tool part number 670377 or a 11 64 drill bit The procedure for setting the float height is as follows Remove the bowl gasket then hold the carburetor in the inverted position Place the tool across the carburetor body opposite and parallel to the float hinge pin Adjust the float height by bending the tab on the float until it touches 29 CARBURETOR SERVICE TIPS SERVICING THE SEAT TecumsehPower carburetors are built with removable seats made out of a material called VITON These seats are easily removed by using TecumsehPower tool 670377 or by bending the end of a paper clip or wire with a 3 32 hook Push the hook through the hole in the center of the seat and remove it Never reuse the old seat always replace with a new seat To install a new seat make sure the seat cavity is clean then moisten the seat with a drop of oil to help it slide into place Position the seat with the grooved side of the seal down and carefully push the seat into its cavity with a 5 32 flat punch until it bottoms out TecumsehPower tool 670377 can also perform this job INSTALLING INLET NEEDLE amp FLOAT Reinstall the inlet needle and the float into the carburetor Make sure the long end of the clip on the inlet needle points
40. owing its response time and causing the engine to Starve for fuel at high speeds 3 The metering lever can be improperly adjusted causing a rich or lean running condition 26 TC SERIES CARBURETOR PUMP DIAPHRAGM OUTLET CHECK VALVE INLET CHECK VALVE PULSE CHANNEL IDLE PARTS MIXTURE ADJUSTING SCREW isi METERING LEVER 7 INLET NEEDLE METERING DIAPHRAGM METERING SPRING ATMOSPHERIC VENT 4 The metering spring can be damaged or the wrong spring installed affecting the acceleration and deceleration characteristics of the engine 5 The metering needle or its seat could be worn causing fuel under pressure from the pump to bypass and flood the engine To troubleshoot the complete carburetor system refer to the Carburetor Troubleshooting Charts in this book SERVICE CARBURETOR INFORMATION To identify a carburetor for replacement on an engine use the model and specification number of the engine If the engine model and specification number are not present for some reason there is a model and code date number stamped on the body of every carburetor Month Year 2 Manufacturing Number Work Day of uu 162 R ALTERNATE LOCATION FOR MANUFACTURING CARBURETOR With the model number you will be able to find all of the information needed to repair or replace the carburetor In the Master Parts Manual or the microfiche carburetor section locate the manufactur
41. pen a small chisel to a sharp wedge point Drive the chisel into the welch plug push down on chisel and pry out of position A new welch plug should be installed bell up as in the illustration Using a punch equal or greater than the size of the plug tap down onto plug Do not dent or drive the center of the plug below the top surface of the carburetor After installation of the welch plug seal the outside edge of the plug with nail polish to ensure that air will not enter the mixing well and that fuel will not leak out Nail polish is resistant to fuel Using different colors for each technician will identify the work of the previous repair person FUEL INLET FITTING If necessary this fitting can be removed by pulling and twisting Be sure to install in the same position as the original Some diaphragm carburetors have a strainer as an integral part of the fitting If the strainer is lacquered or cannot be cleaned replace the fitting When installing a fitting insert the tip into the carburetor body Coat the exposed portion of the shank with Loctite grade A then press it in until the shoulder contacts the carburetor body ALIGNMENT N SEAT RETAINING RING IF EQUIPPED NEEDLE amp a B MAIN T TUBE RING a MAIN NOZZLE goo SPRING T GASKET ALIGNMENT IDLE RESTRICTOR NOTCH HIGH SPEED ADJUSTMENT SCREW ilo E A NUT BRASS PTS M
42. rts Remove all welch plugs o rings and non metallic main nozzles before cleaning carburetor in cleaner DO NOT Use drill bits to clean passages Enlarge passages 5 carburetor in a cleaner over 30 minutes Reuse original choke and throttle shutter screws Interchange bowl nuts Reuse gaskets and rings ENGINE TROUBLESHOOTING When troubleshooting a carburetor other areas such as valves fuel tank venting or gaskets should not be overlooked The carburetor is dependent on the proper operation of the engine to do its job The first step in troubleshooting is to determine if you have a carburetor or an engine problem In orderforthe engine to operate properly the following items need to be checked first 1 Makesure there is a sufficient amount of clean fresh fuel in the tank 2 Check spark plug for proper reach gap and condition Replace if needed or in question Perform an ignition test using spark tester part number 670366 to assure that you have a crisp spark NOTE On older point ignitions models check for proper ignition timing according to the Technician s handbook 3 Checkforfuelflow restrictions into the carburetor Deteriorated fuel line and fuel cap venting are some of the more common restrictions TecumsehPower uses a stainless steel 75 micron filter screen molded into most tanks It is extremely rare for this area to become restricted and should be checked last 4 Check compression by first disco
43. s the cap is removed The fixed main jet is part of the bowl nut A ball plug is visible from the bottom which seals the passage This carburetor also has a serviceable main nozzle emulsion tube It also has a stepped primer bulb HOW TO IDENTIFY TecumsehPower CARBURE LOR CONTINUED SERIES 9 CARBURETOR The Series 9 carburetor is an emissions carburetor that uses the same carburetor body as the Series 8 but with a simple fixed idle system identical to the one used on the Series 6 carburetor It has the idle discharge port located at the 7 o clock position on the throttle end of the carburetor Identify this carburetor by the stepped primer bulb the presence of a non drilled idle mixing well and a serviceable main nozzle emulsion tube SERIES 10 EMISSION The Series 10 carburetor is identical to the Series 8 carburetor with the addition of a choke To assist in cold weather starts It has a fixed idle and main The idle restrictor jet will be capped to prevent access unless the cap is removed The fixed main jet is part of the bowl nut A ball plug is visible from the bottom which seals the passage This carburetor also has a serviceable main nozzle emulsion tube It also has a stepped primer bulb to assist in starting SERIES 11 This carburetor adds a fuel chamber built into the carburetor body that feeds fuel into the venturi during the initial warm up period This patented feature eliminates hunting surging an
44. space heaters clothes dryer electric motors etc 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 such as TecumsehPower Ultra Fresh part number 730245 to the gasoline Fuel stabilizer should be 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 Draining the Fuel System Do not attempt to pour fuel from engine or siphon fuel by mouth Empty fuel tank by using a commercially available suction device designed for use with gasoline Then run the engine until any remaining fuel is consumed Doing so may result in death or serious injury Drain the fuel into an approved container outdoors and away from any open flame or combustion source Be sure the engine is cool NOTE If gasohol has been used put a small amount of unleaded gasoline into fuel tank and repeat preceding instructions then run engine until fuel is used up Oil Cylinder Bore 1 Remove the spark plug wire from the spark plug NOTE Always ground the plug wire when disconnected Pull the starter handle slowly until resistance is felt from compression pressure then stop Slowly
45. this book Now the low and high speed screws can be adjusted to the recommended RPM s HOW TO IDENTIFY A TecumsehPower CARBURE FO E TecumsehPower has a variety of carburetors To help identify these carburetors here are some simple procedures to follow DUAL SYSTEM CARBURETORS The easiest way to identify the dual system carburetor is by the presence of a large primer bulb located on the side of the carburetor The absence of adjustment needles help to identify the carb as well The dual system carburetor is used on 4 cycle vertical crankshaft rotary mower engines SERIES 1 CARBURETORS Series 1 carburetors come in a variety of styles They are used on both 2 and 4 vertical and horizontal shaft engines in the 2 through 7 h p range It is a float style carburetor with a smaller venturi than the Series 3 and 4 carburetors Some will have an adjustable idle and main and others will have a fixed main with an adjustable idle There are also some fixed speed applications that will only have a fixed main system and the idle system will not be drilled SERIES 1 EMISSION This carburetor is similar to the standard Series 1 carburetor The emission equivalent has a fixed idle and main The idle restrictor jet will be capped to prevent access unless the cap is removed The fixed main jet is part of the bowl nut Aball plug is visible from the bottom which seals the passage This carburetor also has a serviceable main no
46. to the edge where the plug meets the casting 14 Note that a seathas a grooved end shown which is installed first into the carburetor casting 15 Install seat into the orifice with the carb tool until it bottoms on the casting 16 Check the float height with the carb tool When the carb tool is removed the float should remain in position The dimension of the carb tool flats are 11 64 19 CARBURETOR CLEANING SERIES 8 11 CONTINUED 17 Adjust the float if necessary by bending the metal tang 18 Bring the float needle assembly down into position then insertthe float hinge pin Always remember the open end of the needle clip on a TecumsehPower carburetor faces out toward the air cleaner side 19 Install a new float bowl bowl O ring and the bowl nut with a new bowl nut gasket 16 EMISSION CARBURETORS The following information will help you better identify some of the common components of emission grade carburetors Emission carburetors will be internally vented On the Series 7 8 9 10 11 and 11 Bridged the atmospheric vent hole is increased in size from earlier model carburetors This passage way leads to the atmospheric vent chamber which is double vented into the bowl cavity This double venting is common on emissions grade carburetors NOTE Emissions certified parts can be identified by a specific series of numbers Emissions carburetors and carburetor parts will be identified usi
47. zzle emulsion tube HOW TO IDENTIFY A TecumsehPower CARBUREILOR CONTINUED SERIES 2 CARBURETORS Series 2 carburetors were used on outboard engines This carburetor is the same as the Series 1 with the exception of the remote adjustable idle mixture screw and a built in fuel pump Series 2 carburetors have a built in fuel pump consisting of a fuel pump element which inflates and deflates with crankcase pulsations which opens and closes two flap valves in the fuel pump thereby pumping fuel from a remote tank to the carburetor float bowl When replacing the fuel pump element install with the slot opening at a 45 angle as illustrated Installation in any other position will damage the diaphragm SERIES 3 amp SERIES 4 CARBURETORS Series 3 and 4 carburetors are generally used on 8 through 12 5 horsepower 4 cycle engines The venturi size of these carburetors are larger than Series 1 and Dual System Carburetors The quickest way to identify these carburetors is by the presence of bosses on each side of the idle mixture screw SERIES 3 amp SERIES 4 EMISSION This carburetor is similar to the standard Series 3 amp 4 carburetor with a few subtle differences The emission equivalent has a fixed idle and main The idle restrictor jet will be capped to prevent access unless the cap is removed The fixed main jetis part of the bowl nut Aball plug is visible from the bottom which seals the passage This carburetor also has a
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