Weber 4 Barrel Carburetor
Contents
1. 9 Accelerator pump linkage should be rechecked at this time Refer to Steps 3 and 4 of Adjustments Accelerator Pump as previously outlined and verify pump is set at 7 16 in 11mm as specified 10 Refer to SECTION 2 Install and adjust throttle cable following instructions appropriate to your power package dq TE WEBER 4 BARREL CARBURETOR 5C 13 Thunderbolt V Equipped Engines ADJUSTING IDLE MIXTURE The procedure for adjusting carburetor idle mixture can be found in the appropriate engine service manu al This procedure also requires that the ignition mod ule be locked in the Base Timing Mode IMPORTANT In order to properly set idle mixture the ignition module MUST BE locked in the Base Timing Mode This is necessary because of the Idle Speed Control feature that exists in the ignition module See information on the previous pages about this feature 1 Using a jumper wire connect the ignition system timing lead 13 PUR WHT wire to a good en gine ground This locks the ignition module into the Base Timing Mode 2 Adjust idle mixture following the procedure in the appropriate engine service manual 3 Remove the jumper wire from the timing terminal ADJUSTING ENGINE IDLE SPEED This procedure should be done with boat in the water drive unit in neutral and engine at normal operating temperature Refer to the Operation and Mainte nance Manual for the correct idle speed2. 1 Disconnect the throttle cable from carburetor Index 5 14 WEBER 4 BARREL CARBURETOR IMPORTANT In order to properly set idle speed the ignition module MUST BE locked in the Base Timing Mode This is necessary because of the Idle Speed Control feature that exists in the ignition module See information on the previous pages about this feature 2 Connect a shop tachometer to engine 3 Using a jumper wire connect the ignition system timing lead 13 PUR WHT wire to a good en gine ground This locks the ignition module into the Base Timing Mode 4 Start engine and allow it to reach normal operat ing temperature Place the remote control lever in forward gear idle position 5 Adjust idle speed to recommended RPM Stop engine Readjust cable barrel and reinstall the throttle IMPORTANT Be sure to disconnect the jumper wire from the ignition system test terminal before attempting to resume normal operations If the jumper wire is left in place the ignition module will operate in the Base Timing Mode This means that the additional timing advance fea tures would not be functioning 7 Remove the jumper wire from the timing terminal 90 823226 1 996 Repair NOTICE Refer to Precautions in this section BEFORE proceeding Removal IMPORTANT Carburetor malfunctions are in many cases caused by the presence of dirt water or other foreign matter in carburetor To aid in
3. Install metering rod springs into each metering rod hole Be certain to install the appropriate color spring refer to Specifications a Spring s IMPORTANT If using existing metering rods be sure that they are reinstalled in the same side from which removed during disassembly Index 90 823226 1 996 25 Carefully install metering rod assemblies in the appropriate holes Push down lightly on metering rods to ensure that plunger will spring up and down N SO ex SAN AN RONG PIT PS 70396 a Metering Rod Assembly s IMPORTANT Some carburetors are equipped with air deflectors that are attached to the screw that holds down the metering rod covers Be sure to reinstall the deflectors if your model carbure tor requires them 26 Position metering rod covers and air deflectors if equipped over metering rods and install screws Tighten securely a Screws b Metering Cover s c Air Deflectors If Equipped te WEBER 4 BARREL CARBURETOR 5C 35 2 Reconnect choke pull off linkage to carburetor 29 Reconnect choke plate linkage Secure with wire Reinstall choke pull off diaphragm Secure with clip two screws and tighten securely a Screw s b linkage Rod 28 Reconnect vacuum hose to choke pull off dia phragm 70391 a Choke Plate Linkage Rod b Wire Clip a Vacuum Hose Index 5C 36 WEBER 4 BARREL CARBURETOR 996 30 Reconnect accelerat
4. WEBER 4 BARREL CARBURETOR 5C 25 23 Remove secondary air valve and weight assem 25 Remove pump jet housing bly by lifting it straight out a Pump Jet Housing 26 Remove gasket from beneath pump jet housing a Secondary Air Valve And Weight Assembly 24 Remove two screws that secure pump jet hous ing 70462 a Gasket Pump Jet Housing 27 Remove check ball and check weight or 70460 check ball and check spring from hole beneath a Screw s pump jet housing b Pump Jet Housing Index 5C 26 WEBER 4 BARREL CARBURETOR 996 IMPORTANT If your carburetor had a ball and weight combination replace with ball and weight If your carburetor used a ball and spring combi nation replace with ball and spring a Check Ball b Check Weight c Check Spring 28 Remove float bowl baffle plates if necessary a Baffle Plate Index 90 823226 1 996 IMPORTANT Do not mix up the primary and sec ondary jets Make note of the jet sizes and their lo cation before removal to be certain that during reassembly they are installed in the carburetor side from which they were removed NOTE If jets are difficult to remove place a screw driver with the correct width in the jet slot and lightly tap the end of the screwdriver with a ham mer 29 Remove primary and secondary jets 70466 a Primary Fuel Jet b Secondary Fuel Jet IMPORTANT Before removing mixture screws check and no
5. and guide in position In 70450 a Accelerator Pump b Plunger Guide c Plunger Washer Not Visible In This View 17 Connect accelerator pump lever to pump rod us ing the S link Secure pump lever with pivot screw Tighten securely Check to ensure lever actuates the accelerator pump 70449 Accelerator Pump Lever Accelerator Pump S Link Retainer Screw aooggw Index 90 823226 1 996 18 Install gasket on top of carburetor ONES ry a DT BI NI tal ES O A a 70448 a Gasket 19 Install inlet filter in bottom of inlet seat Install inlet seat with gasket in place Tighten securely SIN w NN O s 70447 a Seat Gasket Inlet Filter O U WEBER 4 BARREL CARBURETOR 5C 33 IMPORTANT If using existing needles and seats 21 Install floats using hinge pins be sure to reinstall them as matched sets as noted during disassembly 20 Install appropriate inlet needles into inlet seats GN 70400 a Pin s b Floats s 22 Carefully lower top of carburetor onto bottom part 70446 70399 a Inlet Needle s b Seat s IMPORTANT If using existing floats be sure to re install them on the same side as removed Index 5C 34 WEBER 4 BARREL CARBURETOR 996 23 Ensure gasket is properly positioned between the two parts and secure the top to bottom with screws nine total Tighten securely a Screw s 24
6. metering jets in this carburetor are taller than the jets in a standard carburetor Three Step Two Step o v l a Three Step Metering Rod b Two Step Metering Rod METERING ROD HAS THREE STEPS VS TWO Three Step eine n A 4 Two Step AAN Gilera E A 4 13724 PISTON SHAPE IS DIFFERENT AND HAS A SECOND SPRING Three Step 73730 Two Step 13727 996 PISTON ASSEMBLY COVER IS HIGHER ELECTRIC CHOKE The electric choke should be set with marks aligned 74104 Maintenance 73736 Flame Arrestor NOTICE PISTON BORE HAS A STEP ON THREE STEP Refer to Precautions in this section MODEL BEFORE proceeding 5 Remove in the following order a Nut b Sealing washer c Carburetor cover d Crankcase ventilation hoses from flame ar restor and rocker arm covers e Flame arrestor 6 Clean and inspect a Clean flame arrestor in solvent and blow dry with compressed air b Clean crankcase ventilation hoses 73737 c Inspect crankcase ventilation hoses for cracks or deterioration and replace if neces sary Index TAD 90 823226 1 996 WEBER 4 BARREL CARBURETOR 5C 7 7 Install in the following order a Flame arrestor b Crankcase ventilation hoses to flame arrestor and rocker arm covers Carburetor cover Sealing washer e Nut tighten securely 11372 Flame Arrestor with Carburetor Cover Typical Nut Sealing Washer Carburetor Cover Sta St
7. new gasket on top 3 Install carburetor and throttle bracket with attach ing hardware Torque fasteners to 132 Ib in 15 N m 71172 a Throttle Bracket b Attaching Hardware 4 Install fuel line To prevent over tightening hold fuel inlet filter nut with suitable wrench and tighten fuel line connector securely 71173 a Throttle Bracket Not Visible In This View b Attaching Hardware 71173 a Fuel Line b Fuel Inlet Filter Nut Index 5C 16 WEBER 4 BARREL CARBURETOR 996 5 Connect choke linkage rod and install retaining clip 71096 Clip Linkage Rod O B 6 Refer to Section 2 Install and adjust throttle cable following instructions appropriate to your power package N Install flame arrestor and tighten nut securely QO Reconnect battery cables to battery by first in stalling positive batterv cable to positive bat tery terminal Tighten clamp securely Then in stall negative battery cable to negative battery terminal Tighten clamp securely 9 Turn on fuel supply at fuel tank 10 Start engine and check for gasoline leaks If leaks exist STOP ENGINE IMMEDIATELY and re check connections 11 Adjust idle speed and idle mixture as previously outlined under Adjustments 90 823226 1 996 WEBER 4 BARREL CARBURETOR 5C 17 Exploded View Weber Carburetor 90 823226 1 996 a o y WI TIR WA
8. 9666 NOTE Some early production engines had stock secondary jet size of 095 in Refer to Important Service Informa tion for more information Jet Changes for Altitude Mercury Elevation Number Engine Model Manfacturer 0 5000 Feet 5000 9000 9000 Above Number Feet 3310 807826 Primary Jet 092 In 4 3LXH 9666 Metering Rod Stock 686864 Index 5C 2 WEBER 4 BARREL CARBURETOR 90 823226 1 996 UNIT OF MEASUREMENT In mm ALL MEASUREMENTS ARE 1 64 In 0 4 mm Carburetor Adjustment Specifications Engine Model 4 3LX 4 3LXH Gen Carburetor Manufacturer Number 9600 9666 Float Level 1 9 32 in 33 mm Pin 81 mm Pump Rod Hole Location Third Hole From End Accelerator Pump 7 16 in 11 mm Choke Pull Off 15 64 in 6 mm Choke Coil Rod Top Of Rod Even With Bottom Of Lever Hole Preliminary Mixture Idle 1 1 4 Turns Screw Setting Measured from top of carburetor to bottom of S link Remove choke rod from lever hole Choke held closed and choke rod pushed down with top edge of rod even with bottom edge of hole Index 90 823226 1 996 C 3 Description Weber WFB carburetor is unique in design as the main body and flange are cast as a one piece unit This along with the bowl cover make up the two piece construction which is made of light durable alu minum to dissipate heat There are two separate float circuits Each float circuit supplies fuel to a primary low speed c
9. FUEL SYSTEMS WEBER 4 BARREL CARBURETOR Index Table of Contents Page Identification ccc eee 5C 1 Replacement Parts Warning 5C 1 Torque Specifications o o o o 5C 1 Ino ie eo e rra 5C 1 Specifications oooooooooomoooo 5C 2 Jet Changes for Altitude 5C 2 Carburetor Adjustment Specifications 5C 3 Description 0 eee ees 5C 4 Precautions Lm 5C 4 Important Service Information 5C 5 Weber Carburetor Adjustable Accelerator Pump 5C 5 Hard Starting soning reni t Rr xo Ren 5C 5 Carburetor Metering Rod And Jet Identification 5C 6 Maintenance seen 5C 7 Flame Arrestor 0 5C 7 gib 5C 8 AdjJ S ME N S us aet dcbet e acie ein c ap E er acia 5C 9 Accelerator Pump 5C 9 Choke Pull Off 5C 10 A DIOD some PE Ite bur seeded edi kia 5C 10 Float LOVE le TET 5C 11 Idle Speed and Mixture Adjustments 5C 12 Thunderbolt IV Equipped Engines 5C 12 Thunderbolt V Equipped Engines 5C 14 AODA fo pucks dhe EE Fins abe biie bin be 5C 15 Removal 0c ccc cece eee eens 5C 15 Installation sos dead ore aw Sedo E adr 5C 16 Exploded View L 5C 18 Disassembly leues 5C 19 Cleaning and Inspection 5C 28 Reassembly Lsun 5C 29 NOTICE For information an
10. Fuel inlet needle valve and seat Replace with new needle and seat if worn or damaged c Casting surfaces Inspect accelerator pump plunger well for scoring or deposits Replace worn or corroded components d Alllinkage rods and levers Replace if worn or damaged e Accelerator pump and plunger parts Re place pump and parts if worn or damaged f Floatassembly and hinge pin Float weight of each should be the same Replace either if fuel can be heard inside when shaken Check hinge pin and holes for wear Replace compo nents if worn or defective g Throttle valves and shafts Check for bind ing through entire operating range making sure valves open and close completely or for looseness in carburetor body IMPORTANT DO NOT remove throttle valves If any of the throttle parts or float bowl carburetor body shaft bores are found to be worn or dam aged carburetor replacement is required h Choke valve and shaft lever assembly Check shaft and lever for excessive loose ness in air horn Check choke valve and shaft lever assembly for binding through entire op erating range Air horn assembly must be replaced if choke valve and shaft lever are worn 5 Check that choke pull off diaphragm plunger re tracts when vacuum is applied to unit and that it holds vacuum plunger remains seated if vacuum is maintained 90 823226 1 996 Reassembly 1 Install mixture screws needles with springs in place Tu
11. X e or O i l 1 0 a il JW Ae x EN bl c r i Jr aa a EN n NT i Pis 5 E a al E i ja amp N y i D i 1 i 53 ne n EN UUN 9609696 9 OOO OO NN Index 5C 18 WEBER 4 BARREL CARBURETOR 1 Air Deflector 2 2 Screw 2 3 Cover Metering Rod 2 4 Metering Rod Assembly 2 5 Spring Metering Rod 2 6 Fuel Inlet Fitting 7 Sealing Washer 8 Screw 9 Linkage Rod Choke Pull Off 10 Screw 11 Air Horn Carburetor Top 12 Filter Fuel Inlet 2 13 Gasket 2 14 Seat Fuel Inlet 2 15 Needle Valve Fuel Inlet 2 16 Pin 2 17 Float 2 18 Secondary Venturi Cluster 2 19 Baffle Plate Float Bowl 2 20 Screw 4 21 Primary Venturi Cluster 2 22 Gasket 2 23 Jet Primary Fuel 2 24 Screw 2 25 Fuel Pump Injector Housing 26 Gasket 2 Check Weight or Check Spring if So Equipped 28 Check Ball 29 Screw 30 Diaphragm Choke Pull Off 31 Vacuum Hose 32 Idle Mixture Screw 2 33 Spring Idle Mixture Screw 2 34 Gasket Carburetor Base 35 Linkage Rod Choke Plate 36 S Link 37 Accelerator Pump Lever 38 Screw 39 Linkage Rod Accelerator Pump 40 Wire Clip 41 Wire Clip 42 Gasket 43 Screw 4 44 Gasket 2 45 Jet Secondary Fuel 2 46 Secondary Air Valve and Weight Assembly 47 Plunger Washer 48 Plunger Guide 49 Accelerator Pump 50 Spring Accelerator Pum
12. ap between the plate and housing is to be set at15 64 in 6 mm 7 0471 Vacuum Diaphragm Choke Plate Housing Gap Measurement QOO 9 Index 5C 10 WEBER 4 BARREL CARBURETOR 2 Bendchoke pull off linkage to achieve setting giv en in Step 1 a 70471 a linkage Bend Float Drop 1 Measure float drop from bottom side of carburetor top to toe of float lowest part as shown It must be set at 2 in 51 mm a Drop Measurement 2 Iffloat drop is not correct hold hinge pin firmly and bend tab shown as needed 996 IMPORTANT Do not put pressure on fuel needle valve and seat while bending tab or damage may result a Float b Tab Bend Float Level 1 Measure float level from bottom side of carburetor top with gasket in place to toe of float as shown It must be set at 1 9 32 in 33 mm 70468 a Float Level Measurement b Gasket Index 90 823226 1 996 2 If float level requires adjustment hold hinge pin firmly and bend float arm shown as needed IMPORTANT Do not put pressure on fuel needle valve and seat while bending tab or damage may result a Float Level Tab Bend p u ummmmsmmsm3smSmm mmm m m m m m m m m m m m m m m m m m m m m m m m m m m mm m mm Idle Speed and Mixture Adjustments Thunderbolt IV Equipped Engines PRELIMINARY IDLE SPEED AND MIXTURE Initial start settings are given following Make final ad justment with engin
13. d procedures on trouble shooting refer to Section 1C Index 5C WEBER 4 BARREL CARBURETOR 90 823226 1 996 Identification A i 3 Qe at AER TES PRES a ji 70389 a Weber Identification Number Location Replacement Parts Warning Electrical ignition and fuel system components on your MerCruiser are designed and manufac tured to comply with U S Coast Guard Rules and Regulations to minimize risks of fire and explo sion Use of replacement electrical ignition or fuel sys tem components which do not comply with these rules and regulations could result in a fire or ex plosion hazard and should be avoided Index 90 823226 1 996 Torque Specifications Fastener Location in Ib Carburetor To Manifold Fuel Line To Carburetor BAT NA e Tools Part Number Universal Carburetor 91 36392 Gauge Universal Carburetor Stand Torx Screwdriver 15 20 25 Obtain Locally TORX SCREWDRIVERS Weber carburetors will have a star shaped socket in the head of some screws A TORX screwdriver must be used on this type of screw The sizes used are numbers 15 20 and 25 WEBER 4 BARREL CARBURETOR 5C 1 Specifications Mercury Metering Metering Engine Model Carb UMORI Primary Secondary Rod Rod Type Manufacturer Jet Size Jet Size Number Spring Number UMOE Color 4 3LXH Alpha and Bravo WEB 3310 807826 092 089 in 16 686457 Green Gen
14. d weight assem bly a Pump Jet Housing a Secondary Air Valve And Weight Assembly Index 50 30 WEBER 4 BARREL CARBURETOR 996 IMPORTANT Before installing venturi clusters it is important to note which clusters were equipped with a distribution tab This distribu tion tab arrangement varies from one carburetor to another a Distribution Tab s Location And Total Number May Vary 9 Position the secondary venturi cluster gaskets a Gasket Secondary Venturi Cluster Index 90 823226 1 996 10 Install the secondary venturi clusters a Secondary Venturi Cluster 11 Secure each cluster with two screws Tighten se curely 70456 a Screws Two On Each Side b Secondary Venturi Cluster s WEBER 4 BARREL CARBURETOR 5C 31 12 Position the primary venturi cluster gaskets 14 Secure each cluster with two screws Tighten se curely 70455 a Gasket Primary Venturi Cluster a Screws Two Each Side 13 Install the primary venturi clusters b Primary Venturi Cluster s 15 Install the accelerator pump spring into bottom half of carburetor 70454 a Gasket Primary Venturi Cluster One Not Visible In This View b Primary Venturi Cluster 70451 Accelerator Pump Spring Carburetor Bottom O B Index TE 5C 32 WEBER 4 BARREL CARBURETOR 90 823226 1 996 16 Install accelerator pump in top of carburetor hous ing after placing washer
15. diagnosis carefully remove carburetor from en gine without draining fuel from bowl Contents of fuel bowl may then be inspected for contamina tion as carburetor is disassembled 1 Turn off fuel supply at fuel tank 2 Remove carburetor cover Remove crankcase ventilation hoses from flame arrestor then re move flame arrestor IMPORTANT Place a clean cloth in bores of car buretor to prevent dirt and foreign material from falling into bores 3 Disconnect throttle cable attaching hardware from throttle bracket and throttle lever anchor studs Remove throttle cable 71097 Throttle Cable Bracket Attaching Hardware Anchor Studs Index 90 823226 1 996 QOO 9 4 Disconnect retaining clip and choke linkage rod a Retaining Clip b Linkage Rod 5 Remove fuel line and carburetor attaching hard ware Remove carburetor and throttle bracket Discard old gasket from carburetor 71173 71172 a Fuel Line b Attaching Hardware c Throttle Bracket LE WEBER 4 BARREL CARBURETOR 5C 15 6 Remove adaptor wedge plate if so equipped from manifold and discard old gasket 7 Place a clean cloth over intake manifold open ings IMPORTANT Covering intake manifold prevents entry of dirt or foreign material through openings Installation 1 Place appropriate new gasket on intake manifold 2 Ifsoequipped install adaptor or wedge plate de pending on model Place appropriate
16. e a sufficient setting to allow starting the engine 3 Start engine and run at 1500 RPM until engine reaches normal operating temperature DO NOT leave helm unattended while performing idle speed and mixture adjustments following BE CAREFUL NOT TO ACCIDENTALLY ACCELERATE ENGINE WHILE PERFORMING ADJUSTMENTS Index 90 823226 1 996 4 With boat in open water place remote control in forward gear idle position 5 Disconnect throttle cable barrel from anchor stud BE SURE NOT TOLOSE SPACER ON ANCHOR STUD 6 Adjust idle speed adjustment screw to obtain spe cified idle RPM Refer to Section 1B Tune Up Specifications charts NOTE ldle speed must be at specified RPM or less Or engine will be operating on the off idle cir cuit Mixture screw adjustments will be ineffec tive if this condition exists 7 With engine running at or just below specified idle RPM adjust idle mixture screws as follows a Turn idle mixture needle in clockwise until the engine speed begins to decrease due to LEAN mixture b Turn same idle mixture screw outward coun terclockwise until the engine speed begins to decrease due to a RICH mixture c Turnscrewinto a point between these two ex tremes to obtain maximum engine smooth ness and RPM d Repeat procedure with other mixture screw e Readjustidle speed adjusting screw if neces sary to obtain specified idle RPM Place remote control in neutral Turn ignition OFF
17. e running refer to Final Idle Ver 10474 a Idle Speed Screw b Throttle Lever Contact Point 2 Turn idle mixture screws needles in clockwise until LIGHTLY seated then back out 1 1 4 turns Index 50 12 WEBER 4 BARREL CARBURETOR IMPORTANT Do not turn idle mixture screws tightly against seat as damage to seat and or needle may result a Idle Mixture Screws Needles 996 FINAL IDLE SPEED AND MIXTURE IMPORTANT Boat MUST BE in the water and en gine at normal operating temperature to accu rately check and adjust idle speed and mixture Carburetor should be set so that engine idles as smoothly as possible with boat in the water engine normal operating temperature and drive unit in for ward gear To adjust idle soeed and mixture proceed as follows IMPORTANT DO NOT attempt to compensate for other engine problems incorrect ignition timing faulty ignition components low compression vacuum leaks etc with carburetor adjustments This will only cover the problem which must be corrected if engine is to achieve maximum fuel economy and performance 1 Connect a shop tachometer to engine IMPORTANT DO NOT turn idle mixture screws needles tightly into seat as damage to needle and or seat may result 2 If anew or rebuilt carburetor has been installed turn each idle mixture screw until it LIGHTLY con tacts seat if not already accomplished then back out 1 1 4 turns This will provid
18. er c Retaining Screw 15 Remove accelerator pump f l 70450 a Accelerator Pump b Plunger Guide c Plunger Washer Not Visible In This View 16 Remove accelerator pump spring from bottom half of carburetor A lt Ue lt A O E ce p gt PEO S SA gt nate A n L S m J a ise L nal EM l a x x wel ty PUR t zo d 5 ved ues l bud ILI i x al 70451 a Accelerator Pump Spring b Carburetor Bottom IMPORTANT Before removing venturi clusters it is important to note which clusters are equipped with a distribution tab This distribution tab ar rangement varies from one carburetor to another a Distribution Tab s Location And Total Number May Vary Index 5C 24 WEBER 4 BARREL CARBURETOR 17 Remove two screws that secure primary venturi cluster a Screw s Two On Each Side b Primary Venturi Cluster s 18 Remove primary venturi cluster by lifting straight 70454 996 19 Remove gasket from beneath venturi cluster 70455 a Gasket Primary Venturi Cluster 20 Remove two screws that secure secondary ven turi clusters 70456 a Screw s Two Each Side b Secondary Venturi Cluster s Index 90 823226 1 996 21 Remove secondary venturi cluster by lifting it straight up 70457 22 Remove gaskets from beneath secondary venturi clusters 70458 a Gasket Secondary Venturi Cluster dq HE
19. ircuit and a pri mary and secondary high speed circuit The bowls are vented to the inside of the air horn A connecting vent passage effects a balance of the air pressure be tween the two bowls The float needle valves are installed at an angle to provide the best possible seating action on the needles This provides better needle response to float movement also The high speed circuits use staged step up rods in the main metering jets to control the amount of fuel admitted to the nozzles The position of the step up rod is controlled by manifold vacuum applied to the vacuum piston A primary air bleed located in the venturi cluster pre vents a rich condition or bog as the high speed circuit is reactivated after deceleration Small L shaped metal tabs called distribution tab s are attached to some venturi clusters and pro trude into the air stream at the proper location to aid distribution of fuel on selected applications Precautions Always disconnect battery cables from battery BEFORE working on fuel system to prevent fire or explosion Be careful when cleaning flame arrestor and crankcase ventilation hose gasoline is extreme ly flammable and highly explosive under certain conditions Be sure that ignition key is OFF DO NOT smoke or allow sources of spark or open flame in area when cleaning flame arrestor and crankcase ventilation hose Index 5C 4 WEBER 4 BARREL CARBURETOR Be careful when changing fue
20. l system compo nents gasoline is extremely flammable and high ly explosive under certain conditions Be sure that ignition key is OFF DO NOT smoke or allow sources of spark or open flame in area while changing fuel filter Wipe up any spilled fuel im mediately Fuel Supply Connections Avoid gasoline fire or explosion Improper instal lation of brass fittings or plugs into fuel pump or fuel filter base can crack casting and or cause a fuel leak e Apply 592 Loctite Pipe Sealant with Teflon to threads of brass fitting or plug DO NOT USE TEFLON TAPE Thread brass fitting or plug into fuel pump or fuel filter base until finger tight Tighten fitting or plug an additional 1 3 4 to 2 1 4 turns using a wrench DO NOT OVER TIGHTEN Install fuel line To prevent over tightening hold brass fitting with suitable wrench and tighten fuel line connectors securely Check for fuel leaks Make sure no fuel leaks exist before closing en gine hatch A CAUTION DO NOT operate engine without cooling water be ing supplied to water pickup holes in gear hous ing or water pickup inlet or water pump impeller will be damaged and subsequent overheating damage to engine may result 90 823226 1 996 Important Service Information Weber Carburetor Adjustable Accelerator Pump The accelerator pump lever on Weber Carburetors has three holes in it The closest hole to the lever s pivot point is the richest the second hole is lea
21. ner and the hole furthest away is the leanest All production carbs have the pump rod installed in the closest rich est hole If you are having a rich bog on accelera tion move the rod to the second or third hole Weber put the three holes in the lever so the amount of fuel delivered by the accelerator pump could be changed 70472 a Rich b Lean c Leaner Index 90 823226 1 996 Hard Starting If a hard starting condition exists after engine has not been operated for a period of time proceed with the following 1 Before starting engine remove flame arrestor then operate throttle to see if choke closes 2 lfchoke is stuck open check choke stove link rod and choke linkage on both sides of carburetor for cause of sticking Possible paint or interference to rod or linkage 3 If choke plate does not close tight step 2 or 3 then choke link rod will have to be bent to make it short er so it will close choke plate completely Q 73716 a Bend Here To Shorten 4 After installing ensure that the rod does not rub against stove cover or carburetor throughout its travel C 5 Carburetor Metering Rod And Jet Identification METERING ASSEMBLY The metering rod assemblies are different in the fol lowing ways Three Step Two Step l VW Le O Piston Metering Rod Spring Jet Piston Cover ODOQO0OUU Q Index 5C 6 WEBER 4 BARREL CARBURETOR METERING JETS The
22. or pump linkage rod to hole in accelerator pump lever where originally con nected or refer to Important Service Information in this section for information regarding adjust ment Accelerator pump linkage adjustment should be checked at this time refer to Adjust ments Accelerator Pump as previously out lined Secure using wire clip Lm we 70390 a Accelerator Pump Linkage Rod b Wire Clip 31 Refer to Installation and install carburetor Index 90 823226 1 996 WEBER 4 BARREL CARBURETOR addi C 37 THIS PAGE IS INTENTIONALLY BLANK TO ALLOW FOR CORRECTIONS OR ADDITIONS AT A LATER DATE Index 5C 38 WEBER 4 BARREL CARBURETOR 90 823226 1 996 THIS PAGE IS INTENTIONALLY BLANK TO ALLOW FOR CORRECTIONS OR ADDITIONS AT A LATER DATE Index 90 823226 1 996
23. ove depending on 7 Remove metering rod springs amount of service required metering rod cover Screws Turn cover or remove to expose meter IMPORTANT Metering rod springs are color Ing rod coded and should not be interchanged with other carburetors 71095 a Screws a Spring s b Metering Rod Cover s c Air Deflectors If Equipped SHIP 8 Remove nine screws to separate top and bottom IMPORTANT Be careful not to mix metering rods pees OPO QUOT when removing them 6 Carefully lift metering rod assemblies straight out a Screw s a Metering Rod Assembly s 90 823226 1 996 WEBER 4 BARREL CARBURETOR 5C 21 9 Carefully lift off carburetor top and disconnect choke linkage 70399 10 Slide pin out to remove the float IMPORTANT Be careful not to mix up floats after removal 70400 a Pin s b Float s Index 5C 22 WEBER 4 BARREL CARBURETOR 11 Remove inlet needle from seat IMPORTANT Be careful not to mix up inlet needles and seats after removal 70446 a Inlets Needle s b Seat s 996 12 Remove seat gasket and inlet filter IMPORTANT Be careful not to mix up seats after SIN gt 7 A removal 70447 a Seat b Gasket c Inlet Filter 13 Remove gasket from top of carburetor 70448 a Gasket Index 90 823226 1 996 14 Remove accelerator pump lever 70449 a Accelerator Pump b Accelerator Pump Lev
24. p 51 Float Bowl Body Carburetor Bottom Index 90 823226 1 996 Disassembly The following is a step by step procedure for com pletely overhauling carburetor after removal from en gine In many cases however complete overhaul is not necessary and in these cases only the steps re quired to repair the carburetor malfunction should be performed Read the instructions carefully to prevent doing unnecessary steps IMPORTANT Before performing any service on carburetor it is essential that carburetor be placed in a holding fixture to prevent possible damage to throttle valves 1 Remove wire clip to disconnect accelerator pump linkage a Wire Clip b Accelerator Pump Linkage Rod LE WEBER 4 BARREL CARBURETOR 5C 19 2 Remove wire clip to disconnect choke plate link 4 Remove screws from choke pull off diaphragm age bracket to disengage choke pull off linkage NOTE Depending on amount of service required it may not be necessary to remove diaphragm and bracket 70392 a Screws a Wire Clip b Linkage Rod b Choke Plate Linkage Rod NOTE Do not remove vacuum hose if not servic IMPORTANT Metering rods should always be re ing diaphragm moved before separating top and bottom halves of carburetor 3 Disconnect vacuum hose from choke pull off dia phragm a Vacuum Hose b Choke Pull Off Diaphragm Index 5C 20 WEBER 4 BARREL CARBURETOR 996 5 Loosen not necessary to rem
25. rap Crankcase Cover Crankcase Ventilation Hose Flame Arrestor oro Ao oo w Index 5C 8 WEBER 4 BARREL CARBURETOR Fuel Filter NOTICE Refer to Precautions in this section BEFORE proceeding Carburetor inlet fuel filter is installed in bottom side of fuel inlet seat in the carburetor top Refer to Disas sembly and Reassembly to service 10447 a Fuel Inlet Seat with Gasket b Fuel Inlet Filter 996 Adjustments NOTICE Refer to Precautions in this section BEFORE proceeding Accelerator Pump IMPORTANT Refer to Important Service Infor mation in this section regarding the three accel erator pump linkage holes and placement of link age rod 1 Back out idle speed screw until it no longer con tacts throttle lever a Idle Speed Screw b Throttle Lever Contact Point 70473 a Idle Speed Screw b Throttle Lever Index 90 823226 1 996 Close throttle valves completely 3 Accelerator pump is set at 7 16 in 11 mm which is measured from the carburetor top to the bottom of the S link as shown We 4 Adjustment of accelerator pump is done by bend ing the linkage as necessary to achieve the prop er dimension as stated above 10472 70473 a Bend Here WEBER 4 BARREL CARBURETOR 5C 9 Choke Pull Off 1 Choke pull off is checked by holding in on vacuum diaphragm and attempting to close choke plate The g
26. rn idle mixture screws in clockwise un til LIGHTLY seated then back out one and quar ter 1 1 4 turns if previous settings were not noted on disassembly IMPORTANT Do not turn idle mixture screws tightly against seat as damage to seat and or needle may result 70467 a Idle Mixture Screw b Spring Idle Mixture Screw 2 Install the primary and secondary jets Tighten only till snug IMPORTANT Be sure that primary and secondary jets are installed in the appropriate location Be sure that the size matches the same size recorded during disassembly ol JO a Primary Fuel Jet b Secondary Fuel Jet Index 90 823226 1 996 3 Install the float bowl baffle plates if previously removed 70465 c Baffle Plate 4 Into bore beneath pump jet housing location in stall check ball and then check weight or if so equipped check ball and check spring IMPORTANT If your carburetor had a ball and weight combination replace with ball and weight If your carburetor used a ball and spring combi nation replace with ball and spring ki 70464 a Bore b Check Ball c Check Weight d Check Spring LE WEBER 4 BARREL CARBURETOR 5C 29 5 Position pump jet housing gasket 7 Install two screws that secure pump jet housing Tighten securely O 70462 AN a Gasket Pump Jet Housing 6 Install pump jet housing a Screws b Pump Jet Housing 8 Install the secondary air valve an
27. te the number of turns from the fully seated position Also do not mix up the two screws 30 Remove mixture screws 70467 Idle Mixture Screw Spring Idle Mixture Screw G amp Cleaning and Inspection AA CAUTION Rubber plastic parts pump plungers or dia phragms cannot be immersed in carburetor cleaner CAUTION Avoid damage to carburetor Do not leave carbu retor in immersion type cleaner for more than two hours IMPORTANT Do not immerse metering rod springs in carburetor cleaner the color if not natural metal may be removed Clean separately as needed 1 Clean metal carburetor parts in a commercial im mersion type cleaner until all deposits have been removed Follow manufacturer s instructions of cleaner being used for proper cleaning and rins ing procedures AA CAUTION Avoid personal injury Always wear safety glasses when using compressed air 2 Blow out passages with compressed air Do not drill through passages Index 5C 28 WEBER 4 BARREL CARBURETOR IMPORTANT DO NOT use a wire or drill to clean jets passages or tubes in carburetor as this may enlarge orifices and seriously affect carburetor calibration 3 Wipe all parts that cannot be cleaned in immer sion cleaner with a clean dry cloth 4 Carefully inspect all carburetor parts for damage or wear pay particular attention to the following a Idle mixture screws Replace if damaged or worn b
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