FUEL SYSTEMS 72085 ROCHESTER 4 BARREL CARBURETOR 5 C
Tle of Contents Pge Rohester 4 Brrel Cruretor............. 5C-1 Torque Speifitions.................. 5C-1 Tools................................. 5C-1 Speifitions......................... 5C-2 Identifition.......................... 5C-2 Fuel Filter............................ 5C-2 Exploded View........................... 5C-3 Adjustments............................. 5C-4 Aelertor Pump..................... 5C-4 Air Vlve Dshpot...................... 5C-5 Air Vlve Spring Windup................ 5C-5 Flot Level............................ 5C-6 Choke Coil Rod....................... 5C-6 Vuum Brek........................ 5C-7 Flot Weight.......................... 5C-8 Flot Level Adjustments................ 5C-8 Preliminry Idle Speed nd Mixture..... 5C-10 Finl Idle Speed nd Mixture........... 5C-10 5C-0 - - ROCHESTER 44 BARREL CARBURETOR 90-806535940 893
Rohester 4 Brrel Cruretor Torque Speifitions Fstener Lotion l. ft. (N m) Cruretor To Mnifold 13(15) Fuel Line to Cruretor 18(24) Fuel Inlet Filter Nut 18(24) Tools Prt Numer 91-59339 Thometer Desription 91-36392 Universl Cruretor Guge Otin Lolly Torx Srewdrivers #9,#20 & #25 Boroughs Speil Tool nd Equipment In. 2429 N. Burdik Street Klmzoo,MI 49007 (616) 345-5163 BT 8128 B BT-8420 A Flot Grm Sle Flot Level Guge Kent-Moore Speil Tools 29784 Little Mk Rod Roseville,MI 48066 (313) 574-2332 J9789-118 Cruretor Stnd J22769 Needle Vlve Set Remover Wgner Speil Tools Wgner Instruments P.O. Box 1217 Greenwih,CT 06836 (203) 869-9681 Model G.D. 150 Grm Sle (with Round Tip) 90-806535940 893 ROCHESTER 4 BARREL CARBURETOR - 5C-1
Speifitions Units of Mesurement In. (mm) Engine Model MCM 5.0LX MIE 00000 5.7L Competition Ski Cruretor Type Rohester 4MV Merury Numer (Mnufturer Numer) 1347-9661 (17080565) 1347-9415 (17085013) Primry Jet Size.069 Primry Metering Rods.042 Seondry Metering Rods CL Flot Level 15/64(5.9) Pump Rod Hole Lotion Inner Aelertor Pump (Note 2) 23/64(9) Air Vlve Dshpot (Air Vlve Rod).025(0.64) Vuum Brek.080[5/64](2.0) Air Vlve Spring Windup 70-90 Grms Choke Coil Rod (Note 3) Top of Rod even with Bottom Of Hole Idle Mixture Preliminry Setting 2-3 Turns Flot Weight (Mx) 8.3 Grms Note:1. All mesurements re +/ 1/64in. (0.4mm) Note: 2. Aelertor Pump mesurement tken from flme rrestor surfe to pump stem with throttle pltes losed Note:3. Choke vlve must e losed, hoke rod in ottom of hoke lever slot nd hoke oil rod pushed down to end of trvel. Identifition Fuel Filter 72085 - Fuel Line - Fuel Inlet Filter Nut - Gsket (Lrge) d - Gsket (Smll) e - Filter f - Spring d e f 72087 5C-2 - ROCHESTER 4 BARREL CARBURETOR 90-806535940 893
Exploded View 3 2 8 6 7 5 4 1 24 9 23 1 - Air Horn Assemly 2 - Srew 3 - Hnger 4 - Metering Rod, Seondry 5 - Srew 6 - Srew 7 - Srew 8 - Lever 9 - Roll Pin 10 - Pump 11 - Spring 12 - Needle nd Set 13 - Gsket 14 - Pull Clip 15 - Gsket 16 - Metering Rod, Primry 17 - Jet, Primry 18 - Flot Assemly 19 - Pin, Hinge - Flot 20 - Lever, Intermedite Choke 21 - Rod 22 - Clip 23 - Rod 24 - Clip 25 - Srew 26 - Control 27 - Hose 28 - Power Piston 29 - Retiner, Power Piston 30 - Retiner, Pump Dishrge Bll 31 - Bll, Pump Dishrge 32 - Spring, Power Piston 33 - Insert, Flot Bowl 34 - Flot Bowl 35 - Srew, Idle Stop 36 - Spring, Idle Stop Srew 37 - Spring, Filter Nut 38 - Filter, Fuel Inlet 39 - Nut, Fuel Inlet 40 - Gsket 41 - Gsket 42 Rod 25 18 26 22 21 22 20 43 15 27 14 41 13 44 16 19 12 32 17 33 29 28 30 31 37 38 10 11 34 36 35 40 39 45 42 72694 90-806535940 893 ROCHESTER 4 BARREL CARBURETOR - 5C-3
Adjustments! WARNING Avoid gsoline fire or explosion. Improper instlltion of rss fittings or plugs into fuel pump or fuel filter se n rk sting nd/or use fuel lek. Apply #592 Lotite Pipe Selnt with Teflon to threds of rss fitting or plug. DO NOT USE TEFLON TAPE. Thred rss fitting or plug into fuel pump or fuel filter se until finger tight. Tighten fitting or plug n dditionl 1-3/4 to 2-1/4 turns using wrenh. DO NOT OVER- TIGHTEN. Instll fuel line. To prevent over-tightening, hold rss fitting with suitle wrenh nd tighten fuel line onnetors seurely. Chek for fuel leks. 2. Pump rod must e in inner hole of lever. 72088 - Pump Rod - Inner Hole 3. Close throttle vlves ompletely nd mesure from flme rrestor mounting surfe to top of pump plunger stem. Aelertor Pump 1. Bk out idle stop srew until it no longer ontts throttle lever. 72089 72081 - Flme Arrestor Mounting Surfe - Pump Plunger Stem Mesurement 23/64 (9 mm) - Idle Stop Srew - Throttle Lever 5C-4 - ROCHESTER 4 BARREL CARBURETOR 90-806535940 893
4. While supporting lever, end tip of pump lever to otin speified dimension in Step 3. Air Vlve Spring Windup 1. Rotte grm sle until ir vlve egins to open; hek sle reding for orret speifitions. d 72090 - Tip of Pump Lever - Support s Shown Air Vlve Dshpot 1. Set vuum rek diphrgm nd lose ir vlve ompletely. Bend rod to djust gp to speifitions. - Cruretor Csting - Grm Sle - Contt Are of Arm on Air Vlve d - Rotte 72092 d 72091 - Push in Completely - Bend Here to Adjust - Mesurement.025 In. (0.64 mm) d - Fully Closed 90-806535940 893 ROCHESTER 4 BARREL CARBURETOR - 5C-5
2. To djust spring windup, hold tension spring srew nd loosen Allen hed srew. 3. Adjust tension nd retighten Allen srew seurely. 2. Tp flot guge down lightly to ssure free movement. - Inrese - Derese - Srew 72093 72082 - Guge 3. If flot requires djustment, refer to Flot Adjustments lter in this setion, for djustment proedure. Flot Level 1. Strt engine to fill flot owl, run t idle nd insert flot guge into hole next to flme rrestor stud. Choke Coil Rod 1. Push hoke oil rod down. - Guge Hole - Guge 72083 - Vuum Brek Choke Lever - Choke Coil Rod 72096 5C-6 - ROCHESTER 4 BARREL CARBURETOR 90-806535940 893
2. Choke oil rod top must e even with ottom of hole in vuum rek hoke lever. Vuum Brek 1. Set vuum rek ontrol diphrgm y pushing in diretion shown y rrow. 72096 72097 - Top of Rod - Bottom of Hole 3. Bend rod to djust. - Vuum Brek Control Diphrgm 2. Rotte vuum rek hoke lever ounterlokwise until tng ontts vuum rek rod. Choke rod must e t ottom of hoke shft lever slot. 72097 72095 - Tng - Choke Rod - Vuum Brek Rod - Bend Here 90-806535940 893 ROCHESTER 4 BARREL CARBURETOR - 5C-7
3. Bend tng s neessry to otin speified hoke vlve gp. Flot Level Adjustments 1. If new flot or needle nd set re used, end flot rm slightly upwrd t noth for esier djustment. 72130 - Tng - Gp 5/64 In. [.080 In.] (2.0 mm) Flot Weight 72097 - Flot - Flot Arm Noth. Hook needle pull lip over edge of flot rm losest to pontoon. 1. Assemle flot sle ording to instrutions with sle. 2. Compre flot weight to speifitions. 72130 - Pull Clip - Flot Arm 72122 - Flot Sle - Flot 3. Reple flot if it exeeds speifitions. 5C-8 - ROCHESTER 4 BARREL CARBURETOR 90-806535940 893
. Instll retining pin into flot rm nd instll flot nd needle into owl. 2. Hold hinge pin firmly, turn ruretor upside down nd mesure from sting surfe to toe of flot with universl ruretor guge. Chek speifitions. 3. Bend t flot rm noth for djustment to speifitions. If flot requires djustment 72094 72115 - Flot - Needle - Retining Pin IMPORTANT: Top of retining pin must extend ove Flot Bowl sting y.010 in. (0.254 mm) for good pin retention. 72610 - Hinge Pin - Universl Cerutor Guge (P/N 91-36392) - Noth-Bend Here 90-806535940 893 ROCHESTER 4 BARREL CARBURETOR - 5C-9
Preliminry Idle Speed nd Mixture IMPORTANT: DO NOT turn idle mixture needles tightly into set, s dmge to needle nd/or set my result. Note: If new or reuilt ruretor hs een instlled, turn eh idle mixture needle until it LIGHTLY ontts set, then k out 2 or 3 turns. This will provide suffiient setting to llow strting the engine. Initil strt setting; mke finl djustments with engine running.refer to Finl Ilde Speed nd Mixture 1. Turn idle stop srew out until it does not ontt throttle lever, then turn in until it just ontts throttle lever. 72081 2. Turn idle needles until LIGHTLY seted then k out 2 to 3 turns. 72098 - Idle Needles IMPORTANT: Do not turn idle mixture srews tightly ginst set, s dmge to set nd/or needle my result. Finl Idle Speed nd Mixture IMPORTANT: Bot MUST BE in the wter nd engine t norml operting temperture to urtely hek nd djust idle speed nd mixture. Cruretor should e set so tht engine idles smoothly, with ot in the wter, engine t norml operting temperture nd drive unit in forwrd ger. To djust idle speed nd mixture, proeed s follows: IMPORTANT: DO NOT ttempt to ompenste for other engine prolems (inorret ignition timing, fulty ignition omponents, low ompression, vuum leks, et.) with ruretor djustments. This will only over the prolem whih must e orreted if engine is to hieve mximum fuel eonomy nd performne. 1. Connet shop thometer to engine. 2. Strt engine nd run t 1500 RPM until engine rehes norml operting temperture.! WARNING DO NOT leve the helm unttended while performing idle speed nd mixture djustments, following. BE CAREFUL NOT TO ACCIDENTALLY ACCELERATE ENGINE WHILE PERFORMING ADJUSTMENTS. 3. With ot in open wter, ple remote ontrol in forwrd ger, idle position. 4. Disonnet throttle le rss rrel from nhor stud. BE SURE NOT TO LOSE SPACER ON ANCHOR STUD. 5. Adjust idle speed djustment srew to otin speified RPM. 6. With engine running t speified RPM, djust idle mixture needles s follows:. Turn idle mixture needle in (lokwise) until the engine speed egins to drop due to len mixture.. Turn idle mixture srew out (ounterlokwise) until the speed egins to drop due to rih mixture.. Turn srew in to point etween these two extremes to otin mximum engine smoothness nd RPM. d. Repet proedure with other needle. e. Redjust idle speed djustment srew, if neessry, to otin speified RPM. 5C-10 - ROCHESTER 4 BARREL CARBURETOR 90-806535940 893