FUEL AND EXHAUST

GENERAL DESCRIPTION

The 1963 Cadillac fuel system incorporates anew positive crankcase ventilating system, designed to reduce the engine’s air contaminatinghydrocarbon emissions into the air by burningmuch of these fumes. The critical point of thesystem is thepositive crankcaseventilator valve,located at the carburetor insulator fitting, Fig.10-1. This valve controls the flow of fumes entering the engine for burning, and should beservicedat eachoil change.

In positive crankcaseventilating, air enters theoil filler and breather cap, Fig. 10-1. The cap isfitted with a copper meshair filter that takes dustout of the air. The filtered air is passedthroughtiming gear compartments into the crankcase atcrankshaft level. Unburned hydrocarbons arepicked up here and carried through an opening inthe rear of the cylinder block, betweenthe lowerpart of the crankcase and the valve liftercompartment.

The fumes are thencirculated in thevalve liftercompartment cover channel to a mounting point.From here they pass through the connector andhose to the ventilator valve. This valve openswhen the engine is running anddirects fumes intothe carburetor throat, wherethey are addedto thenormal fuel andair mixture and burned.

The positive crankcase ventilator valve ispulled off its seatagainstspring tension by manifold vacuum, Fig. 10-2. At various enginespeedsthe manifold vacuum differs and the valve willtravel in its body allowing fumes to be admittedto the engine.

In time, hydrocarbon deposits accumulate onthe valve, causingit to stick in its travel or plugging it so fumes cannotflow. The following engineconditions can be encounteredwhen the valve isinoperative: When fumes cannotenter the engine,breather backflow occurs andfumes remain in theengine compartment. Sludge, varnish and acidswill develop in the crankcase. These corrosiveagentsmay causeprematurewear on enginepartsand serious engine difficulty.

Carburetion problems will also occur when thefumes arenot properly expelled. This malfunctioncreates poor idling conditions andengine stalling.Even with a properly functioning positive crankcase ventilator valve, rough idling may occur ifidle is adjustedtoo low. Proper engine idle adjustment with an accuratetachometeris essentialfor the 1963 models.

The Cadillac positive crankcaseventilator valveis not interchangeablewith thoseof other engines.Use of other than the proper valve may result inbreatherbackflow andenginedamage.

The fuel tank on all 1963 Cadillac cars ismounted against the lower surface of the trunkcompartment with two support straps. This typeof mounting allows easy removal from belowwithout disturbing sheet metal parts. Felt padsare attached to the tank at the points where thesupport strapsaresecured. Thesepadseliminatethe possibility of a rumbling noise when the trunklid is closed or when driving on a roughroad.

The gasoline filler cap is located behind therear license mounting plate, which is the fillerdoor. The hinged plate swings out from the top.The filler pipe is attachedto the tank at the rearcenter through a flexible hose connector. A ventpipe at the front of the tank allows air to escapefrom the tank when fuel is being added.

The tank unit for the gasoline gageis mountednear the top center of the fuel tank. It containsthe float unit, which is connectedto thegageuniton the instrument panel by one wire, with another

10-1

Connector

___________

Spring

Valve Connector

Fig. 1O- Engine Ventilating System Fig. 10-2 Ventilator Valve

10-2

wire to ground. The fuel outlet line is integralwith tank float unit assembly. It has a specialsaran mesh filter on the inlet end. The filter hasa self-cleaning action, provided by the sloshingaction of the gasoline.

The fuel outlet line is attachedto the gageassembly on the top center of the tank andextendsalong the inside of the right rocker panel to thefuel pump, Fig. 10-3.

The fuel pump is mounted on the engine frontcover. The pump rocker arm is driven by an eccentric machined as an integral part of thecamshaft. Fuel is drawn into the fuel pump on theupward strokeof the diaphragmas the rocker armis moved downward by the cam eccentric againstthe force of the spring. A pulsator diaphragmisused to cushionthe surging of fuel from the pump.The diaphragm is forced downwardby the spring,during the delivery stroke of the pump andexertspressure on the fuel equal to the spring load asthe eccentric travels to minimum stroke. Thisdesign provides a smooth,evenflow of fuel to thecarburetor.

Most engine operatingconditions do not requirefull travel of the diaphragm in the fuel pump.Wheneverthis condition occurs, a spring andlinkarrangementkeeps the rocker arm in contact atall times with the cam eccentric but the diaphragm has only to displace fuel equal to enginedemand.

A fuel filter is mounted on theengineoil fillertube bracket. It receives fuel from the pump andfilters out all dirt particles in excessof approximately .002 inch in diameter. This minimizesflooding and possible clogging of small passagesin the carburetor. Air Conditioner equippedcarsuse a fuel filter with an outlet passagethat returns fuel vapors to the fuel tank under hightemperatureconditions, Fig. 10-3.

A carburetor air inlet baffle is installed on theunderside of the hood. This baffle lessensthepossibility of ice forming inside the venturi whendriving long distances in cool, humid weather.This icing would restrict the required volume ofair from going into the engine, resulting in poorpower andfuel economy.

The carburetor air cleaner incorporates a replaceable, oil-wetted, polyurethane foam elementto remove dirt from the air before it enters thecarburetor and engine.

Certain transmission and vehicle speed conditions are such that suddenreleaseof acceleratorpedal pressuremight causethe engine to returntoo quickly to idle speed,with subsequentstallingof the engine; to prevent this stalling a vacuum-operated throttle check is incorporated on thethrottle linkage. The unit operatesby a combination of spring pressure and engine manifoldvacuum.

Air Conditioner equippedcars have a vacuum-operated idle speed-up control attached to thecarburetor. This device is designedto increasethe engine idle RPM from 480 to 900 when theselector is in the Neutral "N" position and theAir Conditioner switch is "ON". This providesadequate interior cooling and guards againstpossibleengineover-heatingduring idling.

The 1963 Cadillac engine uses either theRochester Model 4GC or Carter Model AFBcarburetor. These carburetors are both of thefour-barrel design, incorporatingtwo primary andtwo secondarybores.

A single exhaust system is used on all 1963Cadillac cars. The system consists of a "Y"exhaust pipe, muffler with aluminizedcover, twosection intermediate pipe, resonator and outletpipe, Fig. 10-3. These units are supported by

Vapor Return Line Vapor Return Line

Fig. 10-3 Exhaust and Fuel Supply Systems

FUEL AND EXHAUST 10-3

clamps and brackets and are insulated from theframe by rubber cushions. The exhaust systemmust be properly aligned to avoid contactwith theframe and the exhaust system support brackets.

A thermostatically controlled heatvalve, at thejunction of the left exhaustmanifold and exhaustpipe, controls the flow of exhaustgasesfrom theleft cylinder head. During the engine warm-upperiod, the valve is closed, forcing thehot exhaust

gases through the ribbed heatpassagein the intake manifold to heatthe intake mixture. Optimumperformance and economy are thereby providedwhen the engine is cold. A branchof this passageconducts exhaust gases up to the carburetor.Thesehot gaseswarm the carburetorin theregionof the Irimary throttle valves and idle ports topreventstalling dueto ice formation during enginewarm-upon cool, humid days.

SERVICE INFORMATION

1. Positive Crankcase VentilatorValve Removal, Cleaning andInstallation

a. Removal and Cleaning

6. Immerse in any good cleaning solvent andblow dry with compressedair.

NOTE: The valve cannot be disassembled.

b. Installation

1. Removeair cleanerand gasket.

2. Remove spark plug wiring clip from its studandposition wiring out of the way.

3. Releaselarge ventilator hoseclampand removehose from ventilator valve.

4. Releasefirst small clamp securing valve toshort length of hoseandremovevalve.

5. Insert .080 inch - .090 inch wire in threadedend of valve to clean orifice inside of valve.

1. To facilitate installation, apply aamount of silicone on both endsof valve.

small

2. Install ventilator valve with smaller endintoshort length of rubber hose. Secure with smallhoseclamp.

3. Connect ventilator hose to ventilator valveandsecurewith large hoseclamp.

4. Install spark plug wiring clip on its stud.

5. Install gasketand air cleaner.

CRANKCASE VENTILATOR VALVE DIAGNOSIS CHART

CONDITION

Slow, unstable idle, rolling, frequent stalling,breather backflow, and oily enginecompartment.

POSSIBLE CAUSE

Valve completely plugged.

Engine operation OK, but breather backflow atheavythrottle, oily enginecompartment.

Valve stuck in closedposition.

Slow, unstable idle, rolling, frequent stalling,breather backflow, and oily enginecompartment.

Valve stuck in openposition.

Rough, fast idle. Engine stalls. No backflow. Valve stuck in intermediateposition.

NOTE: If the valve is inoperative, it should be cleanedor replaced.

10-4 FUEL AND EXHAUST

EXHAUST SYSTEM

2. Outlet Pipe

Removal and Installation

a. Removal

1. Raise rear end of car.

2. RemoveU-bolt andclamp securingresonatorandoutlet pipe to supportbracket.

CAUTION: Resonatorwill be loose.

3. Removeoutlet pipe from resonator.

b. Installation

1. Install outlet pipe on resonator so there isnot more than 5/8 inch betweenrim of resonatorandforward endof outlet pipe, Fig. 10-4.

2. Position hanger blade under U-bolt so thereis 3/4 inch betweenvertical section of bladeandfront edge of hanger. Center U-bolt on hangerblade and center blade in rubber slot of hanger.

3. Install clamp on outlet pipe so there is atleast 1/8 inch between clamp and front edge ofoutlet pipe, Fig. 10-4.

4. Lower car.

3. Resonator Removaland Installation

a. Removal

1. Raise rear end of car.

2. Remove rear clamp securing resonator torear intermediatepipe.

3. Remove front clamp securing resonator torear intermediate pipe.

4. Drive resonator rearward until it separatesfrom rear intermediatepipe.

5. Removeoutlet pipe from resonator.

b. Installation

1. Install outlet pipe on resonator so there isnot more than 5/8 inch betweenrim of resonatorandforward endof outlet pipe, Fig. 10-4

2. Install resonator on rear intermediate pipewith small drain hole in front of resonatorfacingdown.

3. Install clamp that holds resonator to rearintermediatepipe.

4. Install clamp that holds resonatorandoutletpipe to supportbracket.

5. Position hanger blade under U-bolt so thereis 3/4 inch betweenvertical section of bladeandfront edge of hanger. Center U-bolt on hangerblade and center blade in rubber slot of hanger.

6. Install clamp on outlet pipe so there is atleast 1/8 inch betweenclamp and front edge ofoutlet pipe, Fig. 10-4.

7. Lower car.

4. Rear Intermediate PipeRemoval and Installation

a. Removal

1. Remove resonator as described in Note 3.

2. Remove clamp securing rear intermediatepipe to front intermediatepipe.

3. Remove U-bolt securing rear intermediatepipe to support bracket at rear shock absorberupper mount.

4. Separate rear intermediate pipe from frontintermediatepipe.

5. Remove rear intermediate pipe by raisingframe to allow sufficient clearanceover rear axlehousingfor removal.

I 5/16"--....-1/8"

- 3/4,,

- -H-1/8" 5/8"-

5/8"-..io 1/2"

Fig. 10-4 Outlet Pipe Hanger

FUEL AND EXHAUST

b. Installation

1. Install rear intermediate pipe on front intermediate pipe. Make certain there is a minimum of 3/8 inch betweenrear intermediatepipeand frame member, Fig. 10-5. Install clamp thatholds pipestogether.

2. Install U-bolt that holds rear intermediatepipe to support bracket at rear shock absorberupper mount. Support bracket should be centeredin the bracket from side to side andpositionedallthe way forward in rubber slot of supportbracket,Fig. 10-5.

3. Install resonator as described in Note 3.

Make certain all components arealigned and not contacting frame

NOTE:properlymembers.

4. Lower car.

5. Front Intermediate PipeRemoval and Installation

a. Removal

1. Raisecar on hoist or jack stands.

2. Loosen two clamps securing muffler.

3. Drive muffler forwardfrom front intermediate pipe.support muffler.

4. Remove clamp securingpipe to rear intermediatepipe.

until it separatesUse floor jack to

5. Separateand removefront intermediatepipefrom rear intermediatepipe.

b. Installation

1. Fit front intermediate pipe to rear intermediate pipe. Fit front intermediate pipe tomuffler by driving muffler rearward.

2. Align front intermediate pipe so there is atleast 1/2 inch between pipe and No. 4 bodyoutrigger.

3. Position clamp so there is 1/8 inch betweenfront of saddle and forward end of rear intermediate pipe, and 3/8 inch from dimple on frontintermediate to forward end of rear intermediatepipe, Fig. 10-6. Blade must be horizontallyaligned and centered in rubber portion of supportbracket.

4. Hold support bracket blade in position andtighten clamp securing front intermediate pipeto rear intermediate pipe.

5. Tighten two clamps securing muffler.

NOTE: Make certain all components areproperly aligned and not contacting framemembers.

6. Remove floor jack.

7. Lower car.

10-5

front intermediate

6. Muffler Removaland Installation

a. Removal

1. RaiLse car on hoist or jack stands.

Fig. 10-5 Rear Intermediate Pipe Hanger Fig. 10-6 Front Intermediate Pipe Hanger

10-6 FUEL AND EXHAUST

2. Loosen two clamps securing muffler.

3. Drive muffler forward until it separatesfrom front intermediatepipe.

4, Separatemuffler from exhaustpipe and remove muffler.

b. Installation

1. Install muffler on exhaust pipe. Use floorjack to support the muffler.

2, Use floor jack to supportmuffler and installmuffler on front intermediate pipe. Tighten twoclamps securing muffler.

NOTE: Make certain all components areproperly aligned and not contacting framemembers.

3. Remove floor jack.

b. Installation

1, Install exhaust pipe on muffler.

2. Install heat control valve, with gaskets,between exhaust pipe and left exhaust manifold.Be sure face of valve stamped"top" is next tomanifold.

3. Connect exhaustpipe, with gaskets, to bothmanifolds. Tighten nuts to 33 foot-pounds.

4. Tighten clamp between exhaust pipe andmuffler.

5. Remove jack stands.

6. Lower car.

4. Lower car.

7. Exhaust PipeRemoval and Installation

a. Removal

1. Raise front end of car.

2. Disconnect exhaust pipe from both exhaustmanifolds and remove heat control valve fromleft manifold.

3. Remove clamp at front of muffler.

4. Separ4teexhaust pipe from muffler and remove exhaustpipe.

5. Support muffler on jack stands.

6. Remove all gasketmaterial from heat control valve and exhaustmanifold sealing surfaces.

8. Heat Control ValveRemoval and Installation

a. Removal

1. Raise front end of car.

2. Disconnect exhaust pipe from both exhaustmanifolds,

3. Remove heat control valve with upper andlower gasketsfrom left manifold.

4. Remove all gasketmaterial from heat control valve and exhaustmanifold sealing surfaces,

b. Installation

1. Install heat control valve, with newgaskets,and connect exhaust pipe to exhaust manifoldsas described in Note 7b.

2. Lower car.

FUEL SUPPLY SYSTEM

9. Fuel RequirementsTo prevent detonation, only premium fuel with

a minimum octane rating of 100 ResearchMethodand 89 Motor Method should be used. On cars tobe used in foreign countries, where the octanevalue of fuel is known to be below 96 ResearchMethod, the compression ratio must be lowered.This is accomplishedby installing low compression pistons.

If the ResearchMethodoctanerating of available fuel is between 96 and 98, install specialcylinder head to block shims, and retard the

spark timing if necessary.Shims and low compressionpistons are availablethroughthe factoryParts Warehouse.

Fuels with octane ratings from 98 to 100 byResearch Method may be used, when necessary,by retarding the spark timing. Engine fuel requirements are reduced by approximately oneoctane number for each 2-1/2 degrees that thespark timing is retarded from the normal 5 degree setting. Do not retard beyond top deadcenter,

Altitude above sea level also reduces octane

FUEL AND EXHAUST 10-7

requirementsby approximatelyoneoctanenumberfor each 2,000 feet. For this reason, the appropriate spark setting for a particular localityshould be determinedon the basis of the lowestaltitude where the customer may drive with locally available fuels.

Do not "power time" the engine,as variationsin weather conditions will affect the day-to-dayoctane requirements. Never advance the sparkbeyond 50 B.T.D,C.

10. Storage Precautions

Whenever a car is to be put in storagefor anylength of time, all gasoline should be drainedfrom the entire fuel system, including the cariuretor, fuel filter, fuel pump, lines andtank, Thismust be done to assurefreedom from gum deposits that would occurby evaporationof the fuel,

‘Ii. Fuel Tank Removaland Installation

NOTE: When working on or around the fueltank, always have a CO2 fire extinguishernearthe work area. In addition, do not permit anysmoking, open fire, or work of a nature thatcould producea spark in the area.

a. Removal

1, Disconnect fuel gage tank wire at connectorat right of filler cap behind license plate mount.This is the lower connector andis a brown wire.Pull wire down from undersideof car past rearframe member.

2, Raise rear end of car.

3, Drain fuel from tank,

4. Loosen clamp at lower end of filler pipeflexible hose connector.

5, Remove bolt from support bracket of fillerpipe and remove filler pipe through opening betweenbumperand rear endof frame.

6, Disconnect fuel outlet hose at front of tank.

7. If car is equippedwith Air Conditioner, disconnectvapor return hose.

8, Disconnect overflow vent pipe at front oftank.

9. Disconnect fuel gage tank unit ground wireat rear frame cross member.

10. Remove tank support strapnuts andrerriove

b. Installation

1, Raise tank into position and install tanksupport strap nuts. Make sure fuel gage tankunit wire hangsover edgeof tank.

NOTE: Do not tighten tank strap nuts untilfiller pipe is installed.

2. Positionfiller pipe in plateand tightenclampon end of hose connector.

3. Install bolt in supportbracket at top of pipe.

4. Tighten tank strap nuts until 3/4 inch to13/16 inch of thread is exposedon bottom of Jbolts. On 75 seriescars run nut below notch andbreak off notchedend of J-bolt. Be careful not toovertighten tank strap nuts.

5. Con:nect fuel outlet hose.

6. If car is equippedwith Air Conditioner, connect vapor returnpipe.

7, Con:nect overflow vent line.

8. Route tank wire brown over rear crossmember up to right of filler pipe and securetolower right connector.

9. Connect tank unit ground wire to frame.

10, Lower car, add gasoline to tank andcheckfor leaks at filler pipe, vent pipe, fuel line, andvapor return line.

11. Check operationof fuel gage,

12. Fuel Line and Tank Cleaning

Occasionally it may be necessaryto clean outfuel line and tank to remove foreign particlesfrom system, Frequentreplacementof fuel filtersand excessivedepositsof dirt in filter bowl areindicationsthat this may be necessary.

To clean out fuel line, disconnectline at fuelpump and at fuel tank, blow compressed airthrough line in reverse direction to fuel flow,and reconnectline.

For cleaning, fuel tank must be removedfromcar, as described in Note ha, and flushed outto remove all foreign materials. Fuel strainershould also be inspected and replaced ifnecessary.

13. Fuel Line Removal andInstallation

NOTE: When working on or around the fuellines, always have a CO2 fire extinguisherneartank.

10-8 FUEL AND EXHAUST

the work area. In addition, do not permit anysmoking, open fire, or work of a nature thatcould producesparksin the area.

a. Removal of Rear Section

1. Raise rear end of car.

2. Remove right rear wheel.

3. Disconnect fuel outlet line at fuel tank.

4. Remove five clips that secure fuel line toinside of right rocker panel. If car is equippedwith Air Conditioner, a dual clip is used to holdfuel andvapor return lines.

5, Remove two clips, one aheadof and onebehind connectionsbetweenfront and rear sectionsof fuel line.

6. Disconnect the two sectionsof fuel line andremove, rear section by rotating it until it worksfree of axle housing.

b. Removal of Front Section

1. If rear section has not been removed, disconnect front and rear sections at connectionand plug rear line to preventloss of fuel. Removeclip holding front section to frame side member.

2. Disconnect front fuel line at flexible hoseand removefront section.

c. Installation of Front Section

1. Position front section of fuel line and connect it to flexible hose.

2. Secure line to frame with clip at rear endof front section.

3. If rear section of duel line wasnot removed,unplug line and connect froht section to rearsection.

d. Installation of Rear Section

1. Position rear section of fuel line over axlehousing.

2, Connect rear section of fuel line to frontsection, Do not tighten connection,

3. Install five clips along inside of rockerpanel. If car is equippedwith Air Conditioner,larger diameter fuel line should be installedinside andvapor return line on outside,

4. Install clips on both sides of front and rearfuel line connection,

5. Connectfuel line to fuel tank outlet.

6. Tighten fuel line clamps and front to rearfuel line connection.

14. Fuel Pump Tests

1. To check fuel pump capacity, disconnectfuel line at fuel filter inlet and fuel pump outlet.Being careful not to bend tubing, reposition tubingon fuel pump outlet so that fuel may be discharged into a container and secure line to fuelpump.

2. Raise front end of car.

3. Disconnect flexible line at steel fuel supplyline on inlet side of pump near front motormount. Plug steel fuel supply line to keepgasolinefrom draining out of tank.

4, Insert disconnectedend of flexible line intoa quart container of kerosene or solvent. Besure end of hose does not rest against bottomof container and container is at same level asfuel pump.

5. Crank engine until approximately 1/2 pinthas been pumped and then check output. Pumpshould displace a minimum of 280 cc of keroseneper 10 strokes fuel spurts at cranking speed.Seventeen strokes should fill a pint container,If liquid is delivered as specified, pump deliveryis normal, If pump delivery is below normal,check for the following:

a. Diaphragm flange or pulsator cover screwsloose. Tighten screws.

b, Loose connection on inlet side of pump.Tightenfitting andusenew hoseclamp.

c, Flexible inlet line pinched, broken, porous,or obstructed. Replaceflexible line.

d. Check camshaft eccentric for wear visuallyby using mirror and flashlight through mountingflange.

6. If pump does not operate properly afterthese corrections have been made, overhaul orreplace pump.

NOTE: By following the procedure givenbelow, the displacementcapacity of thepump canbe increased by as much as 5 cc per stroke.

7. When installing pump, crank engine untilcam eccentric is at lowest point. With mountingscrews loose, lift up on pump. At the sametime,tighten screws to 15 foot-pounds.

8, To check for pump pressure, remove fuelline at pump outlet and install pressure gage.

FUEL AND EXHAUST

At cranking speed, fuel pump pressure shouldbe 5-1/4 to 6-1/2 poundsper squareinch,

9. If pressure is below 5-1/4 pounds,overhaulpump.

IS. Fuel Pump Removaland Installation

a. Removal

1. Disconnect fuel line betweenfuel filter andpump. Remove line.

2. Release hose clamp securing rubber hoseto fuel pump inlet. Plug end of hose to preventfuel drainage.

3. Remove two cap screws and washersthathold fuel pump to engine front cover andremovepump. Discard gasket.

b. Installation

1. Using new gasket position fuel pump withattaching screws. Tighten screws to 15 foot-pounds.

2. Remove plug and connect rubber inlet fuelhose to pump, securingwith hoseclamp.

3. Install fuel line betweenfuel pump andfilter.

16. Fuel PumpDisassembly and Assembly

. Disassembly

1. Clean outside of pump in solvent and usecompressedair to remove loosedirt andgrease.

2. Mark edges of fuel diaphragm cover andbody with a file to assure correct positioningwhen reassembling.

3. Remove four screws and lock washers andremove pulsator cover and pulsator diaphragm,Fig. 10-7.

4, Removerocker arm return spring.

5. Remove ten screws and remove fuel diaphragm cover from body. Tap cover gently withplastic hammer if cover sticks to diaphragm.

6. If outlet and inlet valves are worn or damaged, remove by driving out with a drift punch.

7. Clamp mounting flange of pump body in avise with soft metal jaws. File peened end ofrocker arm pin until pin can be driven out of

10-9

Gasket

Pulsator Diaphragm

Outlet ValveSpring

Pin

Rocker ArmN

Fuel Diaphragm BusMng

Diaphragm Rod Seal

Gasket

Fuel Diaphragm Cover

Pulsator CoverInlet Valve

Return Spring

Fig. 10-7 Fuel Pump Disassenbled

FUEL AND EXHAUST

body with drift punch. Drive out from peenedend.

8. Remove rocker arm assembly by pressinginward on the fuel diaphragmwhile shakingpumpbody with mountingflange facing downward.

9. Removefuel diaphragmandspring.

10. File off staking burrs that retain diaphragmrod sealand removeseal.

11. Clean body and cover in solvent and blowout all passageswith compressedair.

12. Inspect cover and body for cracks andbreakage. Check for flange warpageon a smooth,flat surface. Replace all parts with new partsfrom repair kit.

b. Assembly

1. Press diaphragm rod seal into body withmetal face toward diaphragm, Fig. 10-7. Retainsealby staking body in four places.

2. Assemble rocker arm, link, and bushing.

3. Install diaphragmspring in pump body. Makesure spring is sitting flat on pump body.

4. Install fuel diaphragm by inserting diaphragm rod through spring and rod seal. Restpump body on a bench and press diaphragmagainst spring pressure. At the same time, insert rocker arm assembly with hook pointingaway from diaphragm and guide hook onto rodslot.

5. Install rocker arm pin. Peen small end ofpin on sameside as previous staking.

6. Install new gasketsand valves in fuel diaphragm cover. Stake valves in place at fourpoints.

NOTE: When pressing valves into place,stamped sheet metal cage and gasket shouldgo in first,

7. Install pulsator diaphragm andcover on fueldiaphragm cover.

8. Place cover assembly on body, making surethat file marksline up.

9. Push on rocker arm until diaphragmis flatacross body flange. Install top cover screwsloosely, just contactcasting.

10. With a suitable tool, push rocker arm tofull stroke and hold in this position while tightening cover screws securely.

17. Fuel Filter Removal andInstallation

a. Removal

1. On Air Conditioner equippedcars, disconnectvapor return line from fuel filter,

2. While holding fuel filter in position, removenuts securing fuel lines to filter inlet andoutlet.

3. While holding fuel filter, remove one boltand lock washer holding fuel filter to oil fillerhousing bracket andremovefilter.

b. Installation

1, Position inlet and outlet lines in fuel filterand start bolt with lock washer that attachesfuel filter to oil filler housingbracket.

2. Tighten fuel filter outlet and inlet line nutswhile holding filter steady.

3. Tighten bolt securing fuel filter to oil fillerhousing bracket while holding filter steady.

4. On Air Conditioner equipped cars, connectvapor return line to fuel filter.

18. Throttle Check Valve-Removal and InstallationFig. 10-8

a. Removal

1. Disconnect accelerator linkage rod at cruisecontrol power unit if so equipped,

2. Remove vacuum hose.

3. Disconnect throttleburetor,

return spring at car-

10-10

11. Carefully install rocker arm return spring. Fig. 10-8 Throttle Check Valve and Relay

FUEL AND EXHAUST 10-11

4. Loosen two relay mounting screwsenoughto 20. Carburetor Removalremove spring clip, and Installation

a. Removalb. Installation

1. Remove air cleaner, mounting stud, and1. Install new check valve on assembly and gasket.

securewith spring clip.2, Disconnectfuel line at carburetor.

2. Tightenrelay mounting screws.3. Disconnect choke heat pipe from choke

3. Connect vacuum hose, housing.

4. Install throttle return spring. 4, Disconnect distributor vacuum line at car5. Connect accelerator linkage rod at Cruise buretor body fitting.

Control power unit if so equipped.5. Disconnect vacuum line at idle speed-up

6. Perform throttle check valve adjustment as control if car is equipped wih Air Conditioner.outlined in Note 26f.

6. Remove front lock nut from carburetor totransmission TV rod and rotate throttle lever

19. Throttle Check Valve and Relay to allow removal of rod from trunnion, Leave

Assembly-Removal and trunnion attachedto throttle lever adapter plate,since the TV rod must be readjusted when car-

Installation Fig. 10-8 buretor is replaced,a. Removal

7. Disconnect throttle return spring and relay1. Disconnect accelerator rod at throttle relay. rod,

2. Remove throttle rod and washer at throttle 8. Disconnect brake vacuum line by removingrod hole. If car is equippedwith Cruise Control, rubber hosefrom tube.disconnect Cruise Control rod and washer atthrottle rod hole. 9. Releasesmall ventilator hoseclampattached

to insulator and removesmall hosefrom insulator3. Pull vacuum hose from vacuum fitting on fitting,

check valve.10. Remove nut that holds spark plug wiring

4. Remove two mounting screws and remove bracket to carburetor. Remove bracket andthrottle relay assembly. position out of way.

5, Remove spring clip that holds check valve 11, Remove three remaining nuts that holdon relay assembly and remove check valve from carburetor to intake manifold and lift carburetorrelay assembly. off manifold,

b. Assembly 12, Remove carburetor insulator and gaskets,also remove stainless steel shim on Carter car

1, Install check valve on relay assemblyand buretors. Discard the two carburetor gaskets.securewith spring clip, The insulator and stainless steel shim may be

used again if they are not warped, cracked or2. Install relay assembly on cowl with two corroded andcan be cleanedup.

screws.b. Installation

3. Connect throttle rod and washer to relay.On cars equipped with Cruise Control, connect 1. Cleansurfaceof intake manifold, carburetor,Cruise Control rod and washer at throttle rod and insulator of any carbon,gasketmaterial, etc.hole,

2. Place new carburetorgasketon top of mani4. Secure vacuum hose to vacuum fitting on fold, place insulator on top of gasket, and place

check valve, secondnew carburetor gasketon top of insulator.

5. Connectacceleratorrod at relay and connect NOTE: On Carter carburetors place thewith cotter pin, stainless steel shim, coated with gasket ce

ment, on top of the secondcarburetor gasket.6. Perform throttle check valve adjustment as Engine will not idle without shim on Carter

outlined in Note 26f. carburetors.

FUEL AND EXHAUST

3. Lower carburetor onto intake manifold studs,

4. Position spark plug wiring bracket in rightfront stud andtighten nut with fingers.

5. Install three remaining nuts on intakemanifold studs. Tighten all four nuts evenly to 14foot-pounds.

6. Position small clamp on short rubber hose.Connect hose to insulator fitting and securewithclamp.

7, Connectdistributor vacuum line.

8. Connectbrake vacuum line.

9. Connect choke heat pipe to choke housing.

10. Connect idle speed-upvacuum line to idlespeed-up control if car is equipped with AirConditioner.

11. Connectcarburetor fuel line at carburetor.Be sure carburetorfuel inlet nut is tight.

12. Install throttle and TV linkage, leaving TVrod lock nuts loose.

13. Install throttle return spring.

14. Install air cleaner mounting stud in carburetor, place air cleaner gasket in position,andinstall air cleaner.

NOTE: Refer to Note 26 for carburetoradjustmentson engine.

21. Carburetor Inspectionand Cleaning

1. Thoroughly clean all metal parts of carburetor in cleaning solvent, with exceptions notedbelow, and dry with compressedair.

CAUTION: Do not wash accelerator pumpplunger assembly,pump boot, or choke thermqstatic coil housing in cleaning solution, Washtheseparts in clean solvent only.

2. Clean and blow out all passageswith compressedair. Remove any gum deposits that mayhave accumulatedwithin carburetor parts. Cleancarbonout of throttle body heatpassage.

3. Make sure all calibrated restrictions, suchas idle ports, air bleeds, or vents are clean, butdo not pass drills through these passages.Usecompressedair only.

4. Check all shafts and their correspondingbearing bores for wear. Check each piston inits respective cylinder. Check for worn or damaged jets and worn holes in ends of various

5, Inspect accelerator pump plunger leather,replacing plunger as an assembly if leather iscreasedor cracked. Inspect check ball in pumpfor free movement, If stuck, replacepump.

6. Examine float needles andseats. If a needleappears grooved,replaceentire set with a factorymatchedneedle,seat, andgasket.

7. Inspect idle mixture adjusting screws forburrs, ridges, or grooves. If wear is evident,replace screws.

8. Inspect floats for dents or leaks. If floatshave any liquid in them, replace float. Inspecthinge pin bores for burrs or wear. Check hingepins for straightness.

9. Clean strainer screens of dirt and lint. Ifdistorted or plugged, these screens should bereplaced.

10. Inspect auxiliary valve assembly, Shaftmust be straight andmust not bind,

11. Carefully check body assembly and valveassembly for wear at throttle valves and bores,and between shafts and their bores. Check forloosevalves on their shafts,

22. Rochester 4GC CarburetorDisassembly

NOTE: Late changes in the appearanceofthe 1963 Rochester carburetor give an incorrect appearanceto some of the figures in thissection, The parts affectedare:

10-12

levers. Fig. 10-9 Idle Speed-Up Control

FUEL AND EXHAUST

5. Float LevelSecondary

6. Float AlignmentSecondary

7. Float DropSecondary

8. AcceleratorPump

9. Fast Idle

10, IntermediateChoke Rod

11. Choke

12. Choke Rod

13. Choke Unloader

14. SecondaryThrottleOpening

15. SecondaryThrottleLockout

1-3/8 inch - Gage No. 13/8 inch - Gage No, 2

Gage No. 1

1-5/16 inch - Gage No. 3

27/32 inch - Gage No. 4

.022 inch - Gage No. 5

One Notch Rich

.040 inch - Gage No. 6

.125 inch - Gage No. 7

.015 inch - Gage No. 8

b. Idle Speed-Up Control RemovalOn Cars Equipped with Air Conditioner

1. Remove three mounting plate to bowl coverscrews and lock washers andremove idle speed-up control and mounting plate, Fig. 10-9. Thesescrews are slightly longer than the remainingbowl cover screws.

Accelerator Pump Lever

10-13

Choke Counterweight LeverAccelerator Pump LeverThe pump lever has one hole instead of five

Fig, 10-9, 10, 11, 12, 21, 24, 25, 28, 29, 30, 31and 32.

Pump Lever Clip

The pump lever clip is a spring clip insteadofa hairpin clip Fig. 10-9, 10, 11, 12, 25, 28, 29,30,31 and 32.

Accelerator Pump Rod

The rod is bent at a different angle Fig. 10-11,12, 25, 28, 29, 30, 31 and 32.

Idle Vent Guard apd Valve

The valve and guard are not used on 1963models Fig. 10-27.

Choke Trip Lever

p Secondary Actuating Lever

/ PowerBrake

VacuumFitting

V

Vent ValveActuating Tang

N1

AcceleratorPump Rod

Screw

Secondary ___-.

Actuating Rod

SecondaryThrottle Lever

-<. /, ‘hoke Rod

/ Fast Idle Cam

/ Throttle Lever

a. Rochester 4GC Off-EngineAdjustments Summarized

Always perform the adjustmentsin the followingsequence, using the designated gage. All gagereferences refer to Rochester 4GC CarburetorSet, J-77l4-03.

Fast Idle Screw

Fig. 10-11 Throttle Linkage

1. Float LevelPrimary

2. Float AlignmentPrimary

3. Vacuum AssistSpring

4. Float DropPrimary

15/64 inch - Gage No. 1

Gage NC. 1

1-3/32 inch - Gage NO, 1

1-1/2 inch - Gage NO, 1

Accelerator Pump Shaft

Choke ShaftLever

Intermediate1Choke Rod ‘.JIntermediateChoke Leve’

I.,,Throttle

Idle Speed-Up LeverVacuum Spark Advance Hole

/ FuelInlet NJt

Idle Mixture Screws

Fig. 10-10 Choke Linkage

10-14 FUEL AND EXHAUST

Power Piston Spring

Power PistonGasket

‘Secondary Seat

Needle

Spring Clip

Secondary Float

Screws

i Choke Valve

Inlet

Gasket "‘

ScreenCounterweight

Trip Lever

Screw

Cover Screw

Lock Washer

AcceleratorPumpLever

Choke Shaft

Bowl Cover

Pump Ro

Float BalanceSpring

Accelerator

VGasket

Secondary InletScreen

Gasket

Primary Seat

Inlet Needle

Spring Clip

‘- Primary Float

Float Pin

Fig. 10-12 Bowl Cover Disassembled

FUEL AND EXHAUST 10-15

c. Bowl Cover Removal

1. Remove fuel inlet nut, screen and gasket,Fig. 10-12.

2. Remove intermediate choke rod from chokeshaft lever by removing small hairpin clip at topof rod. Rotate rod to disengagefrom intermediatechoke shaft lever, Fig. 10-10.

3. Disconnect accelerator pump rod from accelerator pump lever by removing clip at top ofrod, Fig. 10-11.

4. Remove large clip from acceleratCrpumplever.

5, Remove clip at acceleratorpump shaft. Remove accelerator pump lever from bowl coverboss.

6. Remove choke counterweight lever and triplever with retaining screw from choke shaft,Fig. 10-11.

7. Remove 13 bowl cover attachingscrewswithlock washersandtriangular identification tag. Oneof the inner bowl cover screws is located in acounterborejust inside the edge of the air horn.On cars equippedwith idle speed-upcontrol, threescrews have been removed previously, as wellas the idle speed-upcontrol.

8. Break bowl cover loose from bowl usingfinger pressure only. Do not attempt to prycover loose. If it sticks, tap gently with a plastichammer.

9. Lift bowl cover assembly straight up andout of the bowl by gripping air horn section. Becareful not to bendfloat assemblies,

d. Bowl Cover Disassembly

NOTE: Keep parts from primary side separate from thoseof secondaryside.

1. With bowl cover inverted, removefloat hingepins, floats, and needles. Remove needles withtheir clips from their floats, Fig. 10-12.

2. Removeand discard bowl cover gasket.

3. If necessary, remove vacuum power pistonfrom bowl cover by depressingplunger and allowing it to snap back several times, It may benecessary to remove burrs around power pistonbore caused by staking. Remove spring underpiston. Be careful not to damagevacuum assistspring and cup retainer on power piston stem.

4. Remove accelerator pump by pulling plungerwith rublber boot upward and out of bowl cover.

NOTE: Inspect accelerator pump to determine if vent checkball is free in bore. If stuck,replaceacceleratorpump assembly.

5. Removeprimary and secondaryneedleseatsand gaskets, using a large screwdriver. Removescreen from primary and secondary sides, Fig.10-12. It is not necessaryto removefloat balancespring or secondaryside,

NOTE: If needle valves and seats are to bereused, it is particularly important to keepneedle valves mated with their correspondingseats.

e. Choke Disassembly

1, Remove three choke coil cover screws andretainers, and remove cover. Do not removethermostatic coil from shaft in cover, as theyare matched and come as a complete assembly,Fig. 10-13.

7Intermediate Choke Rod

Gasket

ScrewScrews

Hairpin Clip Choke Piston Lever Baffle

Gasket

f :1Screws

! Piston Pin

PistonThermostat Coil

And Cover

IntermediateChoke

Shaft Lever

Choke Housing

Fig. 10-13 Choke Disassembled

FUEL AND EXHAUST

2. Remove cover gasket andchoke baffle plate.

3. Remove choke piston lever screw and slidechoke piston out of its vacuum cylinder, Fig.10-13.

4. Disconnect choke piston from choke pistonlever by tapping piston and allowing piston pinto fall into cuppedhand,

5. Remove choke housing from bowl by removing two inner attachingscrews,

6. Remove intermediate choke shaft lever fromchoke housing. Removeanddiscard choke housinggasket.

f. Bowl Disassembly

1. Removeacceleratorpump spring, Fig. 10-14.

2. Invert bowl and catch aluminum inlet checkball in cuppedhand,

3. Remove pump inlet retainer and screen.

4. Remove power valve and gasket with largescrewdriver, Fig. 10-15.

5. Remove primary and secondary venturiclusters by removing three attaching screwsandlock washers from each, Fig. 10-14, Removegasketsfrom clusters anddiscard gaskets. Brassbaffles in main wells under primary cluster maybe removed if necessary. Do not attempt to remove idle tubes or nozzles from venturi cluster,

6, Remove hot idle compensator and gasketfrom secondary side by removing two smallself-tapping screws, Fig. 10-14. Discard gasket.Do not bend or distort hi-metal strip. Idle compensator cannot be repaired or recalibrated inthe field. If defective, it must be replaced.

7. Remove primary and secondarymain metering jets using a large screwdriver.

8. Remove T-shaped pump discharge checkvalve retainer from primary side with needlenosedpliers, Fig. 10-15. Removecopper spring.Invert bowl and catchpump dischargesteel checkball.

g. Throttle Body Removal and Disassembly

1, Invert carburetor on work bench.

2, Remove fast idle cam and attached chokerod,

3. Remove idle mixture screws and springs.

4. Remove idle air by-pass screw and spring.

5. Remove large screw and lock washer fromdunterbore in center of throttle body.

6. Removethree smaller attaching Phillips headscrewsand lock washers,

7. Break throttle body loose from bowl withfinger pressure only. Do not attempt to pry bowlloose.

8. Remove and discard throttle body-to-bowlgasket.

10-16

Screw3 Req’d

_________

Screw- 2 Required

Lock Washer "‘ Hot IdlePrimary - Compensator

-øiii 1jJ

Gaskets Secondary

Pump InletScreen

Power Valve

Gasket ._- Retainer

Primary Jets

4Accelerator ,..‘V r’Pump Spring

AcceleratorPump

Check Ball

. SpringSteel Check

1

Secondary Jets

/Valve

Primary VenturiCluster

Hot IdleCompensator

SecondaryVenturi Cluster

Baffles

Retainer

Screen

GasketAuxiliary ThrottleValve Assembly

Fig. 10-14 Bowl Assembly Fig. 10-15 Bowl Disassembled

FUEL AND EXHAUST

9. Remove auxiliary throttle assemblyby sliding it out of bowl, Fig. 10-15.

23. Rochester 4GC CarburetorAssemblyNOTE: Carburetor should be completely

cleanedand inspected before assembly asoutlined in Note 21.

Always use new gaskets when reassemblingcarburetor,

a. Throttle Body Assembly

1. Install idle air by-pass screw and spring,Fig. 10- 16. Initial adjustment should be one-and one-half complete turns from fully seatedposition.

2. Install idle mixture screws and springs.Tighten screws carefully so as not to grooeneedles or enlarge seats. Back out each screwtwo turns from lightly seatedposition for initialmixture adjustment.

b. Throttle Body Installation

1. Invert bowl assembly.

2. Slide auxiliary valve assemblyinto bowl withspring cavity opening facing down, Fig. 10-15.

3. Place new throttle body-to-bowl gasket onbottom surfaceof bowl,

NOTE: Gasket is not reversible, Largestprojecting tab must be placed on primary sideof bowl surroundingvacuum passageto powerpiston.

4. Place throttle body assembly on bowl andstart three Phillips headscrewsandlock washersthrough gasketinto bowl, Fig. 10-16.

5. Install and tighten large center screw andlock washer.

6. Tightenthreeouter screwsuniformly.

7. Install fast idle cam with attached chokerod. Tighten screwsecurely.

c. Bowl Assembly

1. With bowl upright, drop large steel pumpoutlet check ball and copper spring into boreunder primary venturi cluster location, Fig.10-15. Install T-retainer in slot in bore, compressing spring.

2. Position smaller aluminum check ball onits seatin bottom of pump well.

Fast IdleScrew-’%

Spring’7 - -.

- Throttle Wc,...Fast Idle

‘

ZJ:JCenter Screw

* ,/ WasherConnecting

* ScrewLinK

Idle AirBy-Pass

‘ Screw

Fig. 10-16 Throttle Body Disassembled

3, Place pump spring in pump bore and compress into position with finger pressure.

4. Install idle compensator and new gasket,using two small self-tapping screws, Fig. 10-14.

5. Install baffles in primary main wells, ifremoved, with projections toward primary bores.Place new gaskets on primary and secondaryventuri clusters and install clusters in bowl,using three screws and lock washers on eachcluster, Fig. 10-14.

6. Install primary andsecondarymain meteringjets in bowl. Primary jets have smaller holesthan secondary jets and are installed in pumpside of carburetor bowl.

7. Install power valve and gasket, Fig. 10-14.

8. Install small pump inlet screenandretainerin bottom, of fuel bowl next to pump well.

d. Bowl Cover Assembly

1. Place fuel screen in inlet nut with gasketand screwinto place.

2. Place a small amount of silicone lubricanton rubber boot andpump plunger shaft.

3, Holding bowl cover upright, install accelerator pump through hole in casting from belowuntil one flange of boot is above casting withthe other flange below.

4. Install accelerator pump lever into bossand guide accelerator pump shaft into hole in

5. Secure lever to boss with large hairpinclip and pump to lever with smaller hairpin clip.

lever.

10-17

Torsion Spring

Idle Mixture Screws

/Springs -

Speed-Up Lever

,_

ThrottleLever

Throttle Body

/

Spring

Pivot ç4.rScrew

FUEL AND EXHAUST

6. Invert cover and install screenon primaryand secondaryneedle seats, Install needle seatsandgasketsin their respectiveholes.

7. If removed, install power piston and spring,being careful not to damagevacuumassist springand cup retainer. Re-stakelightly.

8. Install new bowl cover gasket.

9. Secure needles to floats with clips and install float assembliesusing hingepins.

NOTE: Balance spring must be installedso as to assist closing the needle. Spring mustbe betweenfloat tang andneedleseat.

e. Float Level Adjustment PrimarySide Figs. 10-17 and 10-18

1. All float level adjustmentsshould be madewith bowl covergasketin place.

2, With bowl cover inverted, centerFloat LevelGage, J-77l4-l, on face of cover and positionunder heelof primary floats.

3. With gage held vertical, lower surface ofeach float should just touchgage. This dimensionis 15/64 inch and is not measuredto the seam.

4, If necessary to adjust, bend float arm atcenter with Bending Tool, J-7182-2, Fig. 10-18.Use caution to prevent bending power pistonstem,

5, Slide float gage to toe of primary floats.Lower surface of each float should just touchgage.

6. If adjustment is necessary at either float,carefully bend float arm as required. Lower

surface of each float should be parallel withcovercasting. Recheckfloat level.

f. Float Alignment-Primary SideFig. 10-17

1. Hold gage, J-77l4-l, vertical under floatandcenteredwith bowl cover casting.

2. Float should be centered in cutout portionof gage.

3. If adjustment is necessary,bend float armshorizontally as required. Slide float assemblyfrom side to side on hinge pin to make surefloats do not touch gage. Recheckfloat level iffloat alignment is necessary.

g. Vacuum Assist Spring AdjustmentFigs.10-19 and 10-20

This adjustment will affect fuel level in thebowl because the spring tension varies the fuellevel.

1. Hold bowl cover so floats are hangingdown.

2. Hold power piston in full up position byplacing thumb nail at brass portion of powerpiston, Fig. 10-19.

10-18

Fig. 10-18 Bending Primary Float Arm

Fig. 10-17 Float Level Adjustment - Primary Fig. 10-19 Vacuum Assist Spring Adjustment

FUEL AND EXHAUST

3. Bounce floats lightly to make sure cup retainer on vacuum assist spring is not binding onpower piston stem.

4. Measure distance from gasket to center ofdimple on side of primary float at toe, using1-3/32 inch leg of Float Gage,J-7714-l.

5. If adjustment is necessary, bend slottedtang at center of float arms, up to increasefloatdrop, and down to decrease float drop. Holdvacuum assist cup up to install Bending Tool,J-7182-2, on tang, Fig. 10-20.

h. Float Drop Adjustment-PrimarySide Fig. 10-21

1. Hold bowl cover so floats are hangingdown,Do not hold power piston.

2. With power piston stem releasedand ‘fullyextended, measuredistancefrom gasketto centerof dimple on float at toe, using 1-1/2 inch leg ofFloat Gage,J-7714-1. Bouncefloats lightly beforemeasuringdistance.

3. If adjustment is necessary, bend tang at

rear of ‘float arm toward needleseatto decreasedrop, arid away from seat to increase drop.

i. Float Level Adjustment-SecondarySide Figs. 10-22 and 10-23

1, With gasketin place andbowl cover inverted,install Float Level Gage, J-77l4-1, over heelof secondaryfloat, Fig. 10-22.

2, Highestpoint of floats should just touchgage.

3. If necessary to adjust, bend float arm atcenter with Bending Tool, J-7l82-2. This dimension is 1-3/8 inch.

4. Measure distance from dimple on side ofeach float at toe to bowl cover gasket, using3/8 inch Gage,J-77l4-2, Fig. 10-23.

5. If adjustment is necessary,bend float armas required, then recheckfloat level,

Bending ToolJ-71 82-2

10-19

Fig. 10-20 Bending Primary Float Tang Fig. 10-22 Float Level Adjustment - Secondary

Fig. 10-21 Float Drop Adjustment - Primary Fig. 10-23 Float Toe Adjustment - Secondary

FUEL AND EXHAUST

i. Float Alignment-SecondarySide Fig. 10-22

1. Hold Float Level Gage, J-7714-1,over floatsat heel.

2. Center gage in bowl cover; each float shouldbe centered in gage.

3. If adjustment is necessary,bend float armhorizontally to centerfloat in gage.

4. Slide float assembly from side to side onhinge pin to make sure floats do not touchgage.

k. Float Drop Adjustment-SecondarySide Fig. 10-24

1. Hold bowl cover so floats are hangingdown.Bounce floats lightly before measuringdistance.

2. Measure distance from gasket to center ofdimple on side of float at toe, using 1-5/16 inchGage, J-7714-3.

3. If adjustmentis necessary,bend tangat rearof float arm away from balancespring to increasedrop or toward spring to lessendrop.

I. Bowl Cover Installation

1. Holding bowl cover assembly in upright position, carefully lower into bowl in sucha manneras not to press against floats with hand whileinstalling.

2. Install three inner bowl cover screws withlock washersand tighten; then secure remainingten bowl cover screws. Install identification tagat corner screw above idle by-pass screw.

NOTE: If car is equipped with Air Conditioner, install idle speed-upcontrol to bowlcover on choke side, using three longer screws.One of the longer screws is also an innerbowl cover screw,

3. Place choke rod with choke counterweightlever on choke shaft, with collar inward and tangpointing outward and toward secondary side ofcarburetor, Fig. 10-25.

4. Install choke trip lever with letters "RP"facing outward and with lever projecting abovetang on choke lever. Install retaining screw.

5. Install pump rod into acceleratorpumplever,Secure rod with clip.

m. Accelerator Pump Rod AdjustmentFig. 10-25

1. If carburetor is mounted on engine, disconnect throttle rod so that throttle check willnot keep throttle valves from closing, andmanually open wide choke valve so that throttle valveswill close in their bores.

2, Hold throttle in the full closed position andcarefully place Gage, J-7714-4, on bowl coverwith side marked "pump" closest to pump lever.

3. With throttle closed and gage resting ontop of bowl cover, pump plunger rod shouldenterhole in gagefreely.

4, To adjust, bend pump rod at upper angleuntil pump rod will enter gage freely. Correctdimension for pump rod adjustmentis 27/32 inchfrom top of bowl covercastingto bottom of pumpplunger rod,

n. Fast Idle AdjustmentFig. 10-26

1. Invert carburetor on workbench with fastidle adjusting screw on the second highest step

10-20

Gage J-7714-4

1-5/16" Gage

J-771 4-3

Fig. 10-24 Float Drop Adjustment - Secondary Fig. 10-25 Accelerator Pump Adjustment

FUEL AND EXHAUST

of fast idle cam. Adjust fast idle screwto obtaina clearanceof .022 inch betweenthrottle valvesand primary boreof throttle body on side oppositeidle adjusting needles. Measure throttle openingwith .022 inch Wire Gage,J-77l4-5.

NOTE: This procedure will provide a fastidle which is very close to correct; however,fast idle should be reset with engine running.

o. Choke Assembly

1. Place new choke housing gasket on chokehousing.

2. Install intermediate choke shaft lever inchoke housing from side towardcarburetor,

3. Attach choke housing to bowl with self-locking attachingscrews.

4. Install choke piston on lever with piston pin.

5. Install piston assembly into housing withtang facing outward. Slide piston into vacuLumcylinder, Place piston lever over intermediatechoke lever shaft, and retain with screw whileholding lever towardchoke housing,.

6. Install intermediate chokerod in choke shaftlever. Grooved end of rod goes into choke shaftlever. Retainwith clip.

p. Intermediate Choke Rod AdjustmentFig. 10-27

Choke vacuumpiston must be properly positioned with respect to vacuum slots in choke housingbore to provide proper choke pull-off action.

1. Open throttle slightly, hold choke valveclosed and push lightly on end of choke piston toremove all play in linkage. Then check to seeif choke piston is flush with choke piston bore.

2. Bend intermediate choke rod if necessaryto correctly position choke piston.

q. Choke Adjustment

Choke mechanism must be absolutely free inany position. Mechanism is free if choke willfall openfrom its own weight.

10-21

Fig. 10-26 Fast Idle AdjustmentFig. 10-27 Intermediate Choke Rod Adjustment

Fig. 10-28 Choke Rod Adjustment

FUEL AND EXHAUST

1. Install choke baffle plate.

2, Install choke cover and gasket. Rotatecounterclockwise until cover choke valve is justclosed and index marks align. Set one notchrich, and tighten three cover screws with retainers,

r. Choke Rod Adjustment Fig. 10-28

1. Position’ fast idle screw on secondstep offast idle cam, with screw resting againstshoulderof highest step.

2. Hold choke valve closed so that choke triplever is in contact with choke counterweightlever.

3. With fast idle screwand camin this position,carefully bend choke rod to obtain a clearanceof .040 inch, as measured with .040 inch WireGage, J-77l4-6, betweentop edge of chokevalveand dividing wall in air horn. UseBending Tool,J-1137.

s. Choke Unloader Adjustment Figs. 10-29and 10-301. With choke trip lever in contact with choke

counterweight, move throttle to full open position.

2. Hold in this position and carefully bendtang of fast idle cam to obtain a clearanceof1/8 inch, as measured with .125 inch Gage,J-77l4-7, between top edge of choke valve anddividing wall in cover, Fig. 10-29. Use BendingTool J-5197, Fig. 10-30, on fast idle cam tang.

t. Secondary Throttle OpeningAdjustment

1. With carburetor inverted, move choke tofully openedposition.

2. Rotate primary throttle to full openposition.

3. Check opening of secondarythrottle valves.They should reach wide open position at thesame.time asprimary valve.

4. Check wide open stops on primary andsecondary throttle shafts, and bend tangs withheavy pliers as required to obtain wide openpositions. Tangs should contact stops at sameinstant.

u. Secondary Throttle Lockout AdjustmentFigs. 10-31 and 10-32

1. Position fast idle camand secondarylockoutlever with choke valve partially closed, Fig.10-31.

2. Check clearancebetweenupper edgeof leverand cam with .015 inch Wire Gage, J-77l4-8.

3. Use pliers to bend secondary lockout leverto obtain proper clearance.

4. Open choke valve andopen secondarythrottleslightly to position lockout lever over fast idlecam, Fig. 10-32.

5. Measure clearance between lever and camin this position with .015 inch Wire Gage,

10-22

Fig. 10-30 Bending Unloader Tang

Choke Valve1

Fig. 10-29 Choke Unloader Adjustment

FUEL AND EXHAUST

1. Float Alignment

2, Float Level

3. Float Drop

4. Choke Piston Lever

5. Choke

6. Accelerator Pump

7. Fast Idle

8. Choke Unloader

9. SecondaryThrottleLever

IPump Link

Pump Arm

Fast IdleCon nectar Rod ‘

ThrottleConnector Rods

3/8 inch - Gage

2 inch -

.120 inch - Gage

One Notch

15/32 inch - Gage

.022 inch - Gage

.281 inch - Gage

.020 inch - Gage

No, 1

Scale

No. 5

Rich

No. 3

No. 6

No. 7

No. 8

10-23

ry Lockout Lever5onda

.015" Wire Gage J-7714-8

Fig. 10-33 Idle Speed-Up Control

Fig. 10-31 Secondary Lockout - Choke Closed

J-7714-8, and bend with Tool J-5l97 to obtainspecified clearance.

24. Carter AFB CarburetorDisassembly

a. Carter AFB Off-Engine AdjustmentsSummarized

Always perform the adjustmentsin the followingsequence, using the designated gage. All gagereferences apply to Carter AFB CarburetorGageSet, J-77l2-02.

ChokeConnector ROd’S

Fig. 10-32 Secondary Lockout - Choke Open Fig. 10-34 Primary Throttle Linkage

FUEL AND EXHAUST

10. SecondaryThrottle .020 inch - Gage No. 8Lockout

b* Idle Speed-Up Control RemovalOn Cars Equipped with Air Conditioner

1. Remove vacuum hose from idle speed-upcontrol.

2. Remove two mounting plate to bowl coverscrews and lock washersandremove idle speed-up control, Fig. 10-33.

c. Bowl Cover Removal

1. Remove fuel inlet fitting, gasketandscreen,

2. Disconnect choke connector rod at chokeshaft lever by removing hairpin clip, Fig. 10-34.

3. Disconnect throttle connector rod at pumparm by removing hairpin clip, Fig. 10-35.

4. Remove fast idle connectorrod by removingscrew from front endof choke shaft.

5. Remove fast idle connector rod from fastidle cam.

6. Remove attaching screws with washersandremove power piston cover plates, Fig. 10-36.Hold coverplatesagainstpressurewhen removingscrews,

10-24

Screws And Washers

Power Piston Cover PlatePower

Metering Ri

Power Piston Sprin

Cover ScrewAnd Lock Washer.

Outer Choke, Screw

Shaft Lever Washer-at J

Inner Choke ç Pump Arm Pump Arm

Shaft Lever________Screw

Clip

ThrottleConnector

RodClip

Fast IdleConnector

Rod

Metering Rod Retaining Springs

Power Piston

Metering Rod

Power Piston Spring

Cover Screw And Lock Washer

Cover Screw And Lock Washer

Choke Valve Screws

Choke Valve

Bowl Cover

ShaftClip

Pump

Float Hinge

Float

Connector Rod

Fuel Inlet Fitting

Bowl Cover Gasket

Accelerator Pump Assembly

‘*- Clip

Needle’

Float Needle Seat

Float

Fig. 10-35 Bowl Cover Disassembled

7, Remove two metering rods with pistons andremove springs from piston wells. If necessary,metering rods may be separatedfrom piston byunhooking metering rod retaining springs fromendof individual rods, Fig. 10-35.

8. Remove screw and accelerator pump arm.Remove "5" link,

9. Remove ten bowl cover screws, Fig. 10-36,

and lock washers. Two screws andlock washers

were already removed on cars equippedwith idle

speed-upcontrol.

10, Break bowl cover loose from bowl, using

finger pressure only. Do not attempt to pry

cover loose with tools. If stuck tap gently with

plastic hammer.

11. Lift bowl cover straight up out of bowl as

sembly, being careful not to damagefloats.

FUEL AND EXHAUST

d. Bowl Cover Disassembly

10-25

NOTE: Keep individual float parts groupedso that the same needleandseatarereassembled together. -

1. Remove float hinge pins, floats, float needlesandneedleseatswith attachedgaskets.

2. Removeanddiscardbowl covergasket.

e. Choke Disassembly

1. Remove three thermostatic coil housing attaching screwswith retainersand removethermostatic coil housing with thermostatic coil, Fig.10-37. Do not remove coil from coil housing.

2. Remove gasket and baffle plate, Fig. 10-37.

3. Remove choke lever attaching screw, Fig.10-37, and remove choke piston, lever and linkassembly by rotating piston in bore. Separatepiston and link assembly by removing piston pin.

4. Removethree chokehousing to body attachingscrews, Fig. 10-37, and remove choke housing,lever and0-ring gasket.

f. Bowl Disassembly

1. Remove two screws with lock washers andremove pump jet cluster and gasket, Fig. 10-38.

2. Remove pump discharge check needle fromhole under pump jet cluster by inverting carburetor body.

3. Mark primary venturis for pump or chokeside and remove both primary venturis andgas-

Piston Cover Plates

Choke Shaft Lever

ChokeConnector Rod

Fuel

Fig. 10-36 Choke and Secondary Linkage

Choke LeverAnd Shaft

Coil HousingBaffle

Coil HousingGasket

ThermostaticCoil, Housing

Choke Choke LeverPiston Lever Screw

ChokeChoke

Gasket "0" Ring

IChoke Piston Pin

Choke HousingAttciching Screw

ThermostaticCoil Coil

Retainers Attaching Screws

Fig. 10-37 Choke - Disassembled

FUEL AND EXHAUST

kets by removing four attaching screws withlock washers.

4. Remove two Phillips head screws and remove hot idle compensatorandgasket, Fig. 10-38.Be careful not to damage the bi-metal strip.

5. Mark secondaryventuris for pump or chokeside and remove both secondary venturis andgaskets,by removing four attaching‘screws withlock washers.

6. Removetwo float bowl baffles.

7. Remove auxiliary throttle valve assembly,Fig. 10-39.

8. Remove accelerator pump, and pump return spring,

9, Remove idle mixture screws and springs,Fig. 10-39.

10. Remove large idle air adjustment screwandspring, Fig. 10-39.

11. Remove gaged check ball plug from floatchamberon pump side.

12. Remove primary and secondary meteringjets.

25. Carter AFB Carburetor Assembly

NOTE: Carburetor s ho u 1 d be completelycleanedand inspectedbefore assembly asoutlined in Note 21. Always usenew gasketswhenreassemblingcarburetor.

a. Bowl Assembly

1. Install primary and secondarymeteringjets.Primary metering jets have the larger holes.

2. Install gaged check ball plug in bottom offloat chamberon pump side.

3. Install idle air adjusting screw and spring.Initial adjustment should be three completeturnsfrom fully seatedposition.

4. Install idle mixture screws and springs.Turn screws in finger tight and then back out1-1/2 turns for approximateadjustment.

5. Place auxiliary throttle valves in position,Fig. 10-39.

6. Install the two primary and the two secondary venturi gaskets.

NOTE: The primary gaskets are differentfrom the secondarygaskets and caution shouldbe taken to make sure they are installed correctly in their respectivesides.

7. Position secondary venturis on choke andpump sides of carburetor as marked during disassembly. Auxiliary feed holes should be towardcenter of carburetor, Tighten four screws withlockwashers, A built in interferencewill preventinstalling the secondary clusters on the wrongside.

8. Install hot idle compensatorand gasket onsecondary side using two Phillips head screwswith lock washers,Fig. 10-38,

9. Install primary venturis on choke andpumpsides of carburetor as marked during disassembly, with vent tubes toward secondary side ofcarburetor, Fig. 10-39. A built in interferencewill prevent installing the primary clusters onthe wrong side.

10, Insert pump discharge check needle withpoint down.

11. Install pump jet cluster and gasket, usingtwo screwswith lockwashers,Fig. 10-38.

12, Install float bowl baffles with trademark‘facing primary side of carburetor.

13, Place pump plunger return spring in pumpbore, Fig. 10-38.

NOTE: This spring is matchedin tension tothe acceleratorpump assembly. Install only thecorrect number spring.

b. Bowl Cover Assembly

10-26

iPump Jet Cluster i Pump

Primary Metering Jets Return Spring

Fig. 10-38 Top View of Bowl Assembly 1. Install new bowl cover gasket.

FUEL AND EXHAUST

Primary VenturiAssembly Pump Side

Venturi Gasket

Primary Metering Jets

Secondary Metering Jets

Baffle

Screws And Washers

Secondary VenturiAssembly Pump Side

Venturi Gaskets

Screw

Hot Idle Compensator.Hot IdleCompensator Gasket’

Pump Return SpringFast Idle Screw

And Spring

Screw Idle Air AdjustingScrew And Spring

Idle Adjustment Screw Springs

Inner Throttle Shaft Arm

Throttle Shaft Tang

Outer Throttle Shaft Arm

Throttle ShaftWasher

Screw

Clip

10-2.7

Screws AndWashers

Primary VenturiAssembly Choke Side

Pump Jet Cluster

Venturi Gasket

Pump Jet Cluster Gasket

Pump Discharge Check Needle

Baffle

Secondary VenturiAssembly Choke Side

Auxiliary ThrottleValve Assembly

Idle Adjustment Screws

Lockout

Caged BallBowl Assembly

Throttle Operating Rod

Throttle Return SpringSecondary Throttle

LeverThrottle Shaft Washer

ScrewFlex Spring

Fig. 10-39 Bowl Assembly - Disassembled

10-28 FUEL AND EXHAUST

2. Install float needle seats and gaskets, floatneedlesand float assemblies,making certain thatthe same needle and seat are reassembledtogether.

c. Float Level AdjustmentsFigs. 10-40 and 10-41

1, Align float by sighting down along side offloat to determine if side of float is parallel toouter edge of bowl cover casting. To adjust, bendfloat lever by applying pressure to end of floatwith finger while supporting float lever withthumb. Repeatwith other float.

2, After aligning floats, removeas much clearance as possible betweenarms of float lever andhinge pin lugs on bowl cover. Arms of float levershould be as parallel to inner surface of lugs aspossible. Be sure that floats operatefreely without excessplay or binding on hinge pin.

3, Float level is checked with the bowl coverinverted, bowl gasket in place, and needleseated.There should be a 3/8 inch clearancebetweenthefloat and bowl covergasket. Adjust the float levelby bending the float arm with Gage, J-7712-1.Recheck float alignment after adjusting level.

4. Check the float drop by holding the bowlcover in upright position and measuredistancefrom bottom outer endof each float to bowl covergasket, Fig. 10-41. This distance should be 2inches as measuredwith scale and is not measured to the seam. To adjust, bend stop tabs onfloat brackets.

d. Bowl Cover Installation

1. Install accelerator pump assembly in pumpwell.

2, Hold bowl coverassemblyin upright positionwith the floats suspendedand carefully lowercover into bowl assembly. Be sure that bafflesattachedto cover slide in front of toward floatsbaffles in body,

3, Install bowl coverscrewswith lock washers.If car is equippedwith Air Conditioner leaveoutscrews at the two points wherethe idle speed-upcontrol will be mounted,

NOTE: Longest screw goesin at air cleanergasket surface at rear of carburetor; secondlongest at front of air cleaner gasket surface;next two - 10 ng e s t at idle speed-up controlbracket, and remaining six shortest screwsgoaround outside.

4. Install accelerator pump "S" link into thepump lever so that either end points towardoutside of carburetor driver’s side of car and secure pump arm with screw.

5, Install throttle connector rod in upper holeof accelerator pump arm andconnectwith hairpinclip, Fig. 10-44.

6. Install lower end of fast idle cam rod in fastidle cam with end of rod pointing away from carburetor, Slide inner choke lever over choke shaftwith tang pointing away from accelerator pumpassembly. Install washer. Install outer chokelever over choke shaft with tang aboveinner chokelever tang. Install choke shaft screw.

7. Install metering rod piston springs into bowlcover. Install meteringrods and pistons.

/Gasket

In Place

3/8" GageJ.77]2

IFloat Should Barely Touch

Gage At Outer End

Fig. 10-40 Float Level Adjustment

Bowl CoverGasket

Fig. 10-41 Float Drop Adlustment

FUEL AND EXHAUST

8. Install piston cover plates and screws withwashers,

9. Install fuel inlet fitting, screenand tighten.

e. Choke Assembly and Adjustment

1. Position choke shaft andlever to choke housing from bowl side. Position choke housing 0-ringgasketand securechoke housing to carburetorwiththree screws,Fig. 10-37.

2, Assemble choke piston to link assemblyandposition choke piston and link assembly in chokehousing.

3. Attach choke piston linkage to lower chokeshaft with screw, Fig. 10-42. With piston down,the lower choke shaft lever should be in an upward position.

4, Install choke connectorrod,

5. Inside the choke piston boreon the left side,approximately 1/2 inch down, is a small slot.Take .026 inch Wire Gage, J-77l2-4, and insertthe 1/8 inch end into slot; then close chokevalveuntil piston stops against gage. Opening betweentop edge of choke valve and web of bowl covercasting should be .120 inch. Check this clearancewith .120 inch Wire Gage, J-7712-5, Fig. 10-42.

6. If adjustment is required, bendchoke intermediate rod, using Bending Tool, J-1l37, Fig.10-43.

7. Install choke baffle plate with trade markfacing out and the tabs centered inside the heatandvacuum passagehole.

8. Install cover gasketand thermostatichousingand coil. Set housing at one notch rich, theninstall three screwsandretainers, tighten screwssecurely.

10-29

15/32" GageTool J-7712

/

Fig. 10-42 Choke Piston Lever AdjustmentFig. 10-44 Accelerator Pump Adjustment

Fool No. J-1137

Fig. 10-43 Bending Choke Connector Rod Fig. 10-45 Bending Throttle Connector Rod

FUEL AND EXHAUST

are fully closed

2. Distance from top of bowl cover to topof plunger shaft should be 15/32 inch as measuredwith 15/32 inch Gage, J-7712-3, Fig. 10-44.

3. If adjustment is required, carefully bendthrottle connectorrod at lower angle,using Bending Tool, J-ll37, Fig, 10-45.

g. Fast Idle and Choke ConnectorRod Adjustment Fig. 10-46

1. Turn carburetor upside down and align fastidle screw with second step on fast idle cam.

2. Insert .022 inch Wire Gage, J-77l2-6, inprimary throttle bore opposite idle adjustingscrews.

3. Turn fast idle screwuntil screw just touchesfast idle cam.

4. With carburetorright side up andchokevalvefully closed and choke lever and arm in contact,adjust fast idle connector rod to align secondstep of cam with center of fast idle screw.

h. Choke Unloader AdjustmentFig. 10-47

1. Rotate primary throttle to full openposition.

2, Insert .281inchGage,J-7712-7,betweenupperedge of choke valve and inner wall of bowl coverassembly. Choke valve should give a slight dragon gageunder finger pressure.

3. If adjustment is required, bend unloader lipon throttle lever, using Bending Tool, J-ll37.

i. Secondary Throttle Lever AdjustmentFigs. 10-48 and 10-49

1. Fully open primary and secondarythrottlevalves, In this position, stop lugs on primary andsecondary throttle levers should contact boss onflange.

2. If adjustment is required, bend secondaryactuatingrod.

3. Fully close primary and secondary throttlevalves.

4. With theprimary andsecondarythrottle valvesclosed, there should be .020inchclearancebetweenpositive closing shoes on primary andsecondarythrottle levers, Check clearance,using .020 inchGage, J-77l2-8.

10-30

f. Accelerator Pump AdjustmentFigs. 10-44 and 10-45

1. Be sure that throttle valvesagainsttheir bores,

Fig. 10-47 Choke Unloader Adjustment

022 Wire GageTool J-7712

Fig. 10-46 Fast Idle Adjustment Fig. 10-48 Secondary Throttle Lever Adjustment

FUEL AND EXHAUST

5. If adjustmentis required,bendshoeonprimarylever.

j. Secondary Throttle Lockout AdjustmentFig. 10-50

l,Crack throttle valves andmanually open andclose choke valve. Keep choke valve closed.

2, Tang on secondarythrottle lever should engage freely in notch of lockout dog. There shouldbe a .020 inch clearancebetweentang and notchin lockout dog.

3. If adjustment is required, bendtang on secondarythrottle lever.

4. Set lockout tang tight against stop on flangecasting and partially open secondary throttlevalve. There should be .020 inch contour clearance between tang on secondarythrottle lever andlockout arm. Check clearance using .020 inchWire Gage.

5. If adjustment is required, bend arm whichcomes in contact with flange casting at slot onlockout tang.

6. On cars equippedwith Air Conditioner,installidle speed-upcontrol by securing bracketto bowlcover with two screws.

26. Carburetor Adjustmentson Engine

The following adjustments are made with thecarburetor assembledon the engine. It is necessary that these adjustments be performed in theexact equencepresented.The positive crankcaseventilator valve should be servicedbefore makingadjustments on the engine as this valve affectsthe air to fuel ratio, Note 1.

a. Idle Speed and Mixture Adjustment

1. Disconnect parking brakevacuumdiaphragmline from neutral safety switch andput tapeoverswitch openingto preventanyair leak.

NOTE: Hose must be disconnectedat thislocation to include anycalibrated leakagein thebalance of the system and to maintain vacuumfor the air conditioning controls.

2. Connect tachometerto engine and set parking brake securely. Place transmission selectorlever in neutral.

3. Connectvacuum gageto throttle checkvacuumhoseat rear of enginewith a tee.

4. Start and warm engine to normal operatingtemperature, Be sure that choke is fully off andthat carburetor is on slow idle, with primary andsecondary throttle valves closed. Be sure thatthrottle check is not holding throttles open,

5. Removeair cleaner.

6. On cars equippedwith Rochester4GC carburetor, remove spark plug wires and clip fromtheir bracket to gain accessibility to idle mixturescrews,

7. Loosen front and rear TV rod lock nuts atcarburetor throttle lever trunnion.

8. Place transmission selector lever in either"DR" position.

9. Set idle speedto not more than 480 rpm byadjusting air adjustment screw. Air Conditionershould be operating on cars so equipped. Turningair adjustment screw outward increasesenginespeed, but also leans the mixture suppliedto themanifold. This must be compensatedby adjustmençof the idle mixture adjustment screw Alwaadjust idle mixture screw last Use mrnLr’i4T1’amountof air possible to obtain proper idle speed’.

Outer Throttle Shaft Arm

SecondaryThrottle Lever

Inner ThrottleShaft Arm

10-31

Throttle OperatingI

Rod ‘Flex Spring

Throttle Shaft Tang

Fig. 10-49 Secondciry Throttle Linkage

SECONDARY THROTTLE LOCKOUT ADJUSTMENT

Fig. 10-50 Secondary Throttle Lockout Adjustment

10-32 FUEL AND EXHAUST

10. Turn one idle mixture adjustmentscrew inor out in order to obtain highest readingon bothvacuumgageandtachometer.

11. Repeat Step 10 with other idle mixtureadjusting screw.

12. Resetidle rpm as noted in Step9.

13. Repeat Steps 9-12 until turning mixturescrews will not cause an increase in engineidlerpm, and the smoothestengine idle is obtained.

14. Pressfinger or eraserendof pencilonbrassvalve of idle compensatorlocatedin secondarysideof carburetor to see if speed is affectedbecausecompensator was open. If speeddrops, readjustcarburetor as per Steps 9-13, being sure thatcompensatorremains closed, If idle compensatorstays openmake adjustmentby keepingvalveclosedwith pencil.

15. Install air cleaner and recheck idle, Makefine adjustmentsif necessary.

16. On cars equippedwith Rochester4GC carburetor, clip wires in their bracket.

17, Shut off engineandremovevacuumgageandtachometer,

18. Connect parking brake vacuum diaphragmline.

b. TV Rod Adjustment

If carburetor was removed, the TV rod wasdisengaged. A simple adjustment can be madeas follows, assumingall other rods are in adjustment. For a complete throttle rod and TV rodadjustmentseeNote c.

1. Start engineandbe sure there is a clearanceat the throttle check.

2. Loosen front and rear TV rod lock nuts.

3. Open choke and seat the throttle valves inthe bores.

4. Push end of TV rod toward rear of car toposition transmission throttle lever against itsstop, and hold with light pressure.

5. Turn front locknut against trunnion until allslack is takenup, then tighten nut threefull turns.

6. Turn rear locknut into contactwith trunnionand use two wrenches to tighten nuts. Be careful not to put any binding force on thecarburetor-‘plate.

7. Shut engineoff.

c. Throttle Rod and TV Rod Adjustment

1. Using two wrenches, back off both locknutson TV rod at carburetor to allow free movementof rod in trunnion.

2. Remove cotter pin and washer from carburetor rod trunnion andremovefrom relay bracketlever. On cars equipped with Cruise Control,Cruise Control rod andwasherarealso detached.

3. Place 1/4 inch drill shank through gaginghole in dash relay lever and into dash relaybracket, Fig. 10-8.

4. With engine running set carburetor throttlelever in hot idle position. Air Conditioner "Off".Throttle valves should be seatedin bores.

5. Adjust carburetor throttle rod to allow freeentry into dashrelay lever.

6. Install washer and cotter pin in trunnion.On cars equipped with Cruise Control, installCruise Control rod with washer.

7, Push end of TV rod toward rear of car toposition transmission throttle lever against itsstop andhold with light pressure.

8. Turn front locknut against trunnion untilall slack is taken up. Tightennut threefull turns,

9, Turn rear locknut into contactwith trunnionand use two wrenchesto tighten nuts, Be carefulnot to put any binding force on carburetorplate.

10, Removedrill from relay bracket.

11. Road test car. Adjustment may be alteredone turn either way to improve shift smoothness.

12. If 4-3 downshift cannot be obtained, checkcarburetorfor wide openthrottle andchokeunloaderoperation with accelerator pedal fully depressed.Perform accelerator pedal height adjustment ifnecessary.

d. Acceleration Pedal Height Adjustment

1. Remove cotter key from trunnion on innerside of accelerator pedal arm and remove trunnion from arm.

2. Adjust trunnion either up or downasrequiredto obtain wide open throttle with pedal fullydepressed.

3. Assemble linkage andinstall slushdeflector.

e. Fast Idle Adjustment

1. Start engineandallow engineandtransmissionto reach operating temperature; choke should befully open. Be sure parking brake is applied.

FUEL AND EXHAUST 10-33

2. Shut off engine and remove air cleaner, 3. Let throttle snap shut and observe delaycaused by throttle check. If enginestalls, clearance is too large. If engine races clearanceis

3. Open throttle slightly. Set fast idle screw too small.on second highest step of fast idle cam, againstshoulderof top step.

4. Adjust screw on relay lever accordingly. Aproperly adjusted throttle check will not quite

4. Start engine. Choke valve will be operL be- cause the engine to stall during the above pro-causeengineis fully warmedup. cedure, Clearancebetweenthrottle check plunger

and relay should be approximately .190 inch withenginerunning,

5. Observeidle speedandadjust fast idle screwto give 1700-1750rpm with transmissionin neutral.Returnengineto normalidle andinstall air cleaner. NOTE: Do not perform this operationre

peatedly because transmission may become

NOTE: If stainlesssteel shim is not installed overheated.

with Carter carburetor, theengine will not idle,seeNote 20b,

g. Idle Speed-Up Control Adjustment

6. Shut off engine.

1, Start engineand allow it to warm up.

f. Throttle Check Adjustment

2. Removeair cleaner.NOTE: Allow engine to idle andmake certain

that throttle check plunger is not in contactwith screw in throttle relay lever. 3. Turn Air Conditioner "On".

1. Apply foot brake firmly with left foot. Place 4. With selector shift lever in neutralposition,transmissionin "DR". screw in idle speed-upunit plunger to maintain

an idle speedof 900-950rpm.

2, Openthrottle wide momentarilyto allow enginemanifold vacuum to drop off arid throttle check 5. Return engine to normal idle and shut offplunger to come out, engine. Install air cleaner.

TORQUE SPECIFICATIONS

MaterialNumber

.

ApplicationThread

Size Foot-Pounds

286-M

Special

260-M

Special

286-M

Carburetor to Intake Manifold Nuts

Fuel Tank Drain Plug

Fuel Pump to CrankcaseFront Cover

Exhaust Pipe to Manifold Nuts

Muffler, Resonator& ExhaustPipe Clamp Nuts .

5/16-24

5/8-18

3/8-16 x 1-1/4

3/8-24

5/16-18

14

28

15

33

20

NOTE: Refer to back of Manual, Page 17-1, for bolt and nut markings and steel classifications.

FUEL & EXHAUST

Fig. 10-51 Special Tools

Key Number Name Key Number Name

A

B

C

J-77l4

J-7182-2

J-5l97

Rochester4GC Gage Set

Bending Tool

Bending Tool

D

E

J-ll37

J-77l2

Bending Tool

Carter AFB Gage Set

FUEL PUMP SPECIFICATIONS

NOTE: Testing to be done with entire car at room temperature.

Fuel pressureat idle speed 5-1/4 to 6-1/2 p.s.i.

Fuel pump discharge per stroke at cranking speed 28 cc. minimum

Fuel pump discharge in 17 strokes at cranking speed 1 Pint minimum

10-34

B C D

FUEL & EXHAUST 10-35

ROCHESTER 4GC SPECIFICATIONS

Throttle Bore . Choke Setting 1 Notch RichPrimary 1-7/16"Secondary 1-11/116" Float Level

Primary Gasket to Float Top . 15/64"SecondaryGasket to FloatMain Venturi

,, Heel Bottom 1-3/8"Primary 1-1/8 Primary Power PistonUp 1-3/32"Secondary 1-15/32SecondaryGasketto Dimple 3/8"

Small Venturi,, Float Drop Gasket,to DimplePrimary. . 1/4

Primary Power Piston Down . . 1-1/2"Secondary. 1/4Secondary 1-5/16" ,‘

Low SpeedMetering Accelerator PumpPrimary Side Capacity - 10 Strokes 9-12 ccIdle Tubes .045" Jets .026"Channel Restriction . . . ,. .060"Hi-Speed Bleed .050"Top Bleed, Over Idle Tube,. .052"

Idle By-PassPrimary Throttle Blades 101"

SecondarySideIdle Tubes .030" Idle Mixture ScrewsChannel Restriction . . . . None Turns Open 1-1/2 to 2-1/2Hi SpeedBleed 2 .028"Lower Idle Air Bleed . . . oo"

Idle By-PassAir ScrewTop Bleed, Over Idle Tube. .0D2"Turns Open 1-1/2 to 2

Main MeteringJets056" Idle SpeedPrimary075" Standard 480 RPM in "DR"Secondary

Air Conditionedwith . . 480 RPM in "DR"A/C cm 900 RPM in "N"

050" with Idle Speed-Up"ON"Power Valve Restriction

10-36 FUEL & EXHAUST

CARTER AFB SPECIFICATIONS

Main Venturi

Primary . .

Secondary .

Primary Venturi

Low SpeedMetering andBleedPrimary Cluster

Idle TubesBy-PassEconomizerIdle BleedMain Nozzle Bleed . .

Strut BleedAuxiliary Nozzle Bleed

SecondaryClusters

Auxiliary FeedBleed .

Auxiliary FeedRestrictionAuxiliary Fuel Feed . .

Nozzle BleedAuxiliary Nozzle Bleed .

Metering Jets

Primary 098"Secondary 082"

Float Level. . . 3/8" Top of Floats to GasketFloat Drop . . 2" Bottom of Floats to GasketChokeSetting 1 Notch Rich

Idle Mixture ScrewTurnsOpen 2-1/2

SecondaryAuxiliary Fuel Feed 064"

480 RPM in "DR"480 RPM in "DR"

900 RPM in "N"with Idle Speed-Up"ON"

Throttle Bore

PrimarySecondary . .

1-7/16"

1-11/16"

PrimarySecondary . .

AcceleratorPump

Capacity - 10 Strokes 13ccMm.Jets 028"

1-3/16"1-9/16"

11/32"11/32"

.032"

.049"

.047"

.052"

.028"

.042".028"

.052"

.063"

.063"031"

.043"

Idle Speed

StandardAir Conditionedwith.

A/C on