CARBURETOR - Speedway Motors
Contents
1. CARBURETOR P N 0 80531 INSTALLATION TUNING AND ADJUSTMENT MANUAL 199R10174 1 NOTE These instructions must be read and fully understood before beginning installation If this manual is not fully understood installation should not be attempted Failure to follow these instructions including the pictures may result in subsequent system failure TABLE OF CONTENTS FIT FO DUIS TON css cst acces etc eas te ee eter ee 3 REMOVAL c csssecsececsessecsececsessesucsussesaesucsussesaesussssesuesuesesaesaesssesatsnesnsstsassnssnsateassnsstsatenssesseeatenss 3 INSTALLATION cece eee ee 3 INSTALLATION NOTES 7 CHRYSLER APPLICATIONS a aa 7 FORD APPLIGA TIONS nnmnnn 8 CGM APPLICA ads es tee ened es ev oman cen oe 9 CHOKE ADJUSTMENT ccssececcessesseseccessessesuesessesaesuesessesaessesessesaesessesarsassessesatsnesnsatsaesnsaeeaeeaes 9 IDLE MIXTURE NEEDLES s cescessececcessesseceesessesacsessessesuesessesaesussessesuesensesaesnssnssesassnssesaeeaes 9 FLOAT LEVEL CHECK AND ADJUSTMENT gt c csscsssecescessessesessessessesessessesarsessessesatsnsseeateaee 10 VACUUM2. This allows torque to increase along the 11 peak torque curve Performance is compromised less by holding the secondaries closed little longer than by opening them a little too soon If the opening rate of the vacuum operated secondaries is properly calibrated there should not be a kick only a smooth increase in power should be felt In general heavier cars require stiffer secondary diaphragm springs than light cars Air cleaner configuration and restriction plays an important part in spring selection also so be sure to use your air cleaner when evaluating your vehicles performance after each change DO NOT expect to wing the throttle and see the secondaries begin to open If they do they will probably open too soon Secondaries should open only when the engine is under a load DO NOT clip or trim a spring in an effort to make a spring lighter so that the secondaries will open sooner Strange as it may seem clipping springs actually increases spring rate and will delay opening So in order to tune the secondaries follow the steps below A secondary spring kit 15 available from your local Holley retailer Holley P N 20 13 VACUUM OPERATED SECONDARY TUNING NOTE The Holley Quick Change Diaphragm Housing Cover makes swapping secondary springs a matter of loosening two screws It is available under P N 20 59 1 Remove the choke cap and choke housing to gain access to the third screw retaining the vacuum diaphragm to the mai
3. cylinder distribution and ultimately total engine performance However some manifolds may be universal Such as Weiand 8004 Please check with Holley s Technical Service Department if you have any questions REMOVAL 1 Remove the air cleaner exercising care to carefully detach any vacuum lines from the air cleaner and marking them so they can be reassembled to the air cleaner in the same manner 2 Remove the existing carburetor by the following procedure A Carefully disconnect the fuel line WARNING Carefully protect the open end of the fuel lines so that no foreign particles can enter Wrap the end of the fuel line with a clean lint free cloth Disconnect and mark all vacuum lines and wiring if any to the carburetor Disconnect the PCV hose Disconnect the choke rod or heat tubes if equipped Disconnect and remove the throttle linkage and automatic kickdown linkage Save all retaining clips Unbolt and remove the carburetor from the manifold TS 3 Ifthe intake manifold is being changed at this time install the new manifold according to the manifold s manufacturer s directions Since we are not familiar with all manifold instructions Holley cannot accept responsibility for their validity INSTALLATION 1 Install the carburetor mounting studs not provided in the proper location on the intake manifold carburetor flange 2 Place the new carburetor flange gasket provided with the carburetor in the prope
4. you achieve the highest possible vacuum reading without adjusting the curb idle speed screw Turn screws in to lean the mixture Turn them out to richen the mixture Curb idle speed screw Figure 9 3 Now that the idle mixture is set it may be necessary to go back and reset the idle speed using the curb idle speed screw as shown in Figure 9 4 vacuum gauge is not available use a tachometer to obtain the highest RPM IDLE MIXTURE IDLE MIXTURE SCREW SCREW Figure 10 Figure 11 ROUGH IDLE AND VACUUM LEAKS If a rough idle persists after the engine has been started and the mixture screws adjusted check for manifold vacuum leaks These could result from unplugged vacuum fittings or a carburetor flange gasket that was torn during installation Recheck for proper attachment of all vacuum lines and check the lines for cracks If the manifold was changed a manifold vacuum leak could occur at the cylinder head manifold surface due to damaged gaskets or improper torquing Frequently manifold vacuum leaks occur from the valley side of the manifold These are very difficult to detect unless a discernible whistle can be heard NOTE In most cases when rough idle occurs after a carburetor manifold change they result from manifold vacuum leaks similar to those described above Assuring a proper manifold installation rather than assuming the carburetor is not functioning properly will ultimately save time FLOAT LEVEL CHECK AND ADJUS
5. OPERATED SECONDARY THROTTLES s sscessscessecesceseesesseseeseseesessesensesarsesseeaee 11 VACUUM OPERATED SECONDARY TUNING sessecescessecessesesessesessesersessesensessesensesenseeees 12 JETTING MAIN JETS 13 POWER VAVE S 13 CARBURETOR SPECIFICATIONS ssssssecescessessesescessessesessessesaesessesarsuesessesatsssnsaesaeentseeaseaeees 14 INTRODUCTION CONGRATULATIONS on your Holley carburetor purchase We feel that you have purchased the finest performance carburetor manufactured today Should you need information or parts assistance please contact our Technical Service Department at 1 270 781 9741 Monday through Friday 7 a m to 5 p m CST Please have the part number of the product you purchased on hand when you call To preserve warranty these instructions must be read and followed thoroughly before and during installation NOTE The 0 80531 carburetor is a 50 state emission legal replacement carburetor for 1965 69 V 8 applications In California those vehicles must have been originally equipped with a four barrel carburetor These carburetors have been designed and calibrated as a universal replacement carburetor for passenger cars and light truck applications equipped with V 6 and V 8 engines It is designed for use on square flange intake manifolds Carburetor adapters are not recommended to adapt to spread bore intake manifolds since adapters may have an adverse affect on cylinder to
6. TMENT Primary and secondary float adjustments are set at the factory but variations in fuel pressure could cause a change in these settings The following procedure shows how to make these adjustments WARNING Extreme caution must be exercised while adjusting the float levels as fuel spillage may occur 10 1 Start the vehicle Turn the electric fuel pump if so equipped 2 Carefully remove the float level sight plug 3 Observe the sight plug for the fuel level If none is seen the level is too low Fuel should be even with the bottom of the sight plug hole If fuel comes pouring out of the sight hole the float is set too high NOTE A properly set float level will have the fuel level located at the bottom edge of the sight hole as shown by the line Figure 12 FLOAT LEVEL SIGHT PLUG LOCK SCREW FLOAT LEVEL ADJUSTING NUT PROPER FUEL LEVEL Figure 12 4 To adjust shut down the engine 5 Loosen the lock screw on top of the fuel bowl just enough to allow you to turn the adjusting nut Hold the screw in position with the screwdriver 6 Using a 5 8 wrench turn the adjusting nut in the appropriate direction Clockwise to lower the float level and counterclockwise to raise the float level 7 Turn the adjusting nut in increments of 1 4 of a rotation 8 Retighten the lock screw 9 Restart the vehicle and observe the sight plug hole 10 Repeat steps 1 through 8 as necessary 11 Reinstal
7. This procedure is unsafe because sparking can occur either at the coil or at the distributor end of the coil wire and ignite any fuel spilled in the engine compartment CAUTION The use of a quality in line fuel filter such as Holley P N 162 523 is mandatory as a safeguard against possible flooding which could result from unfiltered particles becoming lodged between the fuel inlet needle and its seat This can result in fire if a spark is present or backfire occurs in the engine compartment Air cleaner filter elements should be blown clean with compressed air at 6 000 miles and replaced at 12 000 miles to assure maximum protection Now would be the perfect time to upgrade to a Holley Powershot air filter Holley P N 120 146 10 Connect the electric choke lead supplied to the positive terminal of the choke cap The other end must be connected to a good ignition activated 12 volt source Hookup of this wire is not optional WARNING Connecting the choke cap to the ignition or ignition coil could result in unacceptable choke operation poor fuel economy and possible engine misfiring since the voltage delivered to the spark plugs will be severely reduced by the drain imposed by the choke cap Suitable ignition activated 12 volt sources are most electrical relays as well as the leads to accessories such as windshield wipers DO NOT connect this wire to the original equipment O E electric choke source This may not be a 12V source 11 Che
8. ain body 9 Reinstall the air cleaner and test drive the vehicle JETTING MAIN JETS Due to varied applications that a universal performance carburetor will work with a few tips on jetting are provided to help you understand their purpose 1 Out of the box jetting is extremely close for most applications 2 Carburetors are calibrated at 70 at sea level Decrease the jet size primary and secondary one number for every 2000 ft increase in altitude 3 Holley jets are broached flowed and stamped according to flow rate NEVER drill jets as this seriously alters flow characteristics Stamped numbers are reference numbers and DO NOT indicate drill size 4 In most cases it will be unnecessary to increase jet size more than four numbers greater than out of the box jetting Exceptions could arise when the carburetor is mounted on a very large volume plenum ram manifold 5 Spark plugs provide the best indication of proper jetting Consult an ignition manual for proper reading of spark plugs POWER VALVES The number stamped on a power valve such as 65 indicates the manifold vacuum below which the power valve is operational In this case all manifold vacuums below 6 5 Hg the power valve is operating Generally a 65 power valve is sufficient for most high performance applications that have a manifold vacuum of 12 Hg or higher However some problems can result with radically cammed machines equipped with automatic transmis
9. and or temperature sensing valve as originally connected Again use 5 as necessary If any questions arise about the hose connections consult the proper service manual C Plug any vacuum source not used Connect the PCV hose to the PCV fitting in the carburetor base plate Connect the power brake and or PCV hose to the fitting as shown in Figure 7 FULL MANIFOLD VACUUM TEE PCV POWER BRAKE VACUUM PORT Figure 7 9 In some cases the existing fuel line will have to be cut and connected to a dual feed fuel line with a length of rubber fuel hose and a clamp WARNING During the fuel line installation DO NOT allow any foreign particles to enter the fuel lines which could then cause flooding and may result in a fire WARNING Keep the fuel line away from the EGR valve if equipped on the intake manifold If installation requires cutting the metal fuel line cut the fuel line with a good tube cutter This will minimize the chance of producing metal chip particles If a hacksaw must be used then metal chips must be removed WARNING all cases where the fuel line has been cut it is essential that it be clean to insure that no metal particles enter the fuel bowl after the new carburetor installation Remove the fuel line at the pump and blow the line clean with compressed air DO NOT use the procedure where the coil wire is disconnected the engine cranked for a few revolutions and the fuel collected in a container
10. cing an existing Holley Carburetor you may need to purchase Holley P N 20 91 spring and perch kit for Ford automatic transmissions 1 Install the throttle ball lockwasher and retaining nut to the carburetor throttle lever in the same position as the existing carburetor 2 Insert the transmission kickdown screw with the black retaining clip on the transmission kickdown lever Figure 2 This assembly must be installed according to the detailed drawing Figure 3 Transmission a Kickdown 6 Spring Perch Transmission Kickdown Adjusting Screw Throttle Stop Lever Retainer Black Clip Transmission Transmission Kickdown Kickdown Spring Adjusting Screw Figure 2 Ford applications 3 Remove the lock out screw from the kickdown lever Figure 4 4 Install the transmission kickdown spring between the transmission kickdown lever and spring perch Figure 2 THROTTLE TANG INSIDE VACANT TUNNEL KNUCKLES TUNNEL KNUCKLES INCORRECT Screw amp Clip will move 29 Lockout CORRECT 5 Screw amp Clip firm and secure Figure 3 Ford applications Figure 4 Ford applications GM APPLICATIONS WARNING If you are using this carburetor with a GM overdrive transmission TH700R4 or a TH200R4 you must use a transmission kickdown cable bracket Holley P N 20 95 and stud Holley P N 20 40 Otherwise SEVERE transmission damage WILL result This carburetor is not de
11. ck the voltage source with a volt ohm meter to assure proper voltage and choke operation Make sure that the other terminal of the choke cap is grounded well Provision of a good ground and 12 volt source that can supply enough current to the choke cap is essential for proper choke operation 12 Start the engine and check the fuel lines and inlet fitting for possible leaks NOTE The recommended fuel pressure is 5 7 psi Use an adjustable fuel pressure regulator Holley P N 12 803 if it is higher than 7 psi 13 Recheck to assure all existing vacuum hoses are attached properly Plug any fittings not used 6 14 With engine at operating temperature the idle speed to the manufacturer s specifications see page 9 for idle adjustment 15 Shut off the engine and readjust the throttle operated transmission linkage if necessary On installations that have a kickdown actuating switch the passenger s side of the firewall it might be necessary to readjust it according to manufacturer s service manual FORD APPLICATIONS WITH AUTOMATIC TRANSMISSIONS With the engine off push the transmission kickdown rod rearward until it stops and hold it in position Push the throttle lever rearward to its wide open throttle position and adjust the transmission kickdown screw to come in contact with the transmission kickdown lever tang WARNING With the engine off recheck the assembled linkage for sticking and or proper return to the id
12. ibit one or more of the following symptoms black smoke from the tail pipe poor driveability when cold poor gas mileage misses or rough idle 2 Ifthe fast idle RPM is too low or too high for your preferences SHUT DOWN THE ENGINE Advance the throttle to wide open exposing the fast idle set screw below the choke housing See Figure 8 3 Using a 1 4 open end wrench turn the screw clockwise to increase the RPM or counterclockwise to decrease the RPM The factory setting should give you a 1500 1600 RPM fast idle speed NOTE All vacuum ports must be plugged at this time FAST IDLE SPEED SCREW y I Be qx m 827 3 i Figure 8 IDLE MIXTURE NEEDLES Idle mixture needles control the air fuel mixture at idle These have been preset at the factory and SHOULD NOT need any adjustments However if you feel that adjustment is necessary you can use the following procedure to do so When tuning the idle mixture you re actually tuning for the best manifold vacuum Idle mixture needles are found on the primary metering blocks If you change one idle mixture needle you must change the other idle mixture needle by the same amount Here are the proper steps for setting the idle mixture needles 1 Attach the vacuum gauge to a manifold vacuum port the throttle body Figure 7 2 Adjust each idle mixture screw Figures 10 amp 11 1 8 turn at a time alternating between each screw Turn them equally until
13. l sight plug when complete VACUUM OPERATED SECONDARY THROTTLES Many people have the misconception that opening the secondary throttles sooner will provide increased performance and quicker drag strip times Others think they must feel a kick when the secondaries engage Still others believe that they should disconnect the vacuum diaphragm and make the secondaries open mechanically Before going any further let s discuss these points in a reverse order First if we could make our vacuum operated secondary carburetors perform better by opening the secondaries mechanically it would be to our advantage to do so since all that vacuum actuating hardware is expensive and requires much time and money to calibrate Mechanical secondary carburetors all utilize a secondary pump shot to prevent bogging when the secondaries are opened Secondly those who feel a kick when the secondaries engage are actually feeling a flat spot during initial acceleration because the secondaries have already begun to open and have weakened the fuel delivery signal to the primary boosters The engine is struggling to increase speed and what they actually feel are the secondary nozzles crashing in as the engine finally reaches the speed where it provides the proper fuel delivery signal to primary and secondary venturi Third opening the secondaries early causes the situation described above The secondaries must not open until the engine requires the additional air
14. lbs to assure proper fuel metering GENERAL Some very important factors to optimize efficiency and performance include Correct engine timing correct spark plug gap and heat range ignition components in good working order and correct operation of exhaust heat valve WARNING automatic transmission vehicles only install the transmission kickdown adjustment screw and black retaining clip as correctly indicated Failure to attend to this detail may result in a sticking wide open throttle or dangerous uncontrolled engine speed INSTALLATION NOTES CHRYSLER APPLICATIONS WARNING This carburetor is not designed for use with any Chrysler automatic overdrive transmission SEVERE transmission damage may result from improper application use 1 Unless you are replacing an existing Holley carburetor which already has a lever extension arm you may need to purchase and install a throttle lever extension Holley P N 20 7 on the carburetor Remove the throttle stud and nut from the original carburetor You can purchase a new stud from your Holley dealer Holley P N 20 67 Install the stud in the throttle extension lever Figure 1 Throttle Stud P N 20 67 Throttle Lever Extension P N 20 7 Figure 1 Chrysler applications FORD APPLICATIONS WARNING This carburetor is not designed for use with any Ford automatic overdrive transmission SEVERE transmission damage may result from improper application use NOTE Unless repla
15. le position 16 Place the air cleaner gasket Supplied on the sealing flange and install the air cleaner 17 With some air cleaner configurations it may be necessary to use an air cleaner spacer to provide adequate clearance between the carburetor and the air cleaner Holley offers such a spacer Holley P N 17 13 Depending on the overall height obtain the proper length 1 4 x 20 stud and install in the carburetor airhorn Close the hood slowly to ensure adequate clearance between the air cleaner stud and the hood WARNING Inadequate clearance between the air cleaner and the throttle lever could result in throttle sticking and uncontrolled engine speed Check the clearance between the throttle lever and air cleaner for proper operation Check the clearance between the air cleaner and the hood before closing the hood completely MAINTENANCE WARNING Fuel system components including fuel lines and the carburetor should be inspected periodically to assure no fuel leakage and to ensure the soundness of the hoses Today s clean emissions engines provide higher temperatures in the engine compartment These high temperatures promote faster aging of non metallic materials Hoses that exhibit surface cracks when bent to 180 should be replaced The presence of liquid fuel demands tightening of fittings hose replacement and retorquing of the fuel system component flange nuts Periodically check the torque on the fuel bowl screws to 25 30 in
16. n body Figure 13 2 Remove three screws attaching secondary vacuum diaphragm to the main body Figure 14 a Figure 13 Figure 14 3 Remove the clip retaining the diaphragm plunger to the secondary throttle lever using a small flat blade screwdriver Figure 15 VACUUM PASSAGE CORK GASKET WITH CHECK BALL Figure 15 Figure 16 4 Remove the four screws securing diaphragm cover 5 Gently remove the cover Take care as not to tear the diaphragm or loose the check ball Figure 16 12 6 Change the spring Make sure that the new spring seats on the stud cast into the underside of the cover The stiffer the spring the later the secondaries will open 7 When reassembling secondary diaphragm parts exercise care to properly align the vacuum passage in the casting with the cut out in the rubber diaphragm and make sure the check ball is in place DO NOT pinch or tear the rubber diaphragm TIP To make reassembling the diaphragm easier push the diaphragm arm into the housing and form the diaphragm into a mushroom shape Figure 17 Then position the diaphragm over the bolt holes and vacuum port Hold the diaphragm in that position with your fingers while inserting the spring cover and bolts to avoid disturbing the position of the diaphragm CORRECT Figure 17 8 Make sure the cork gasket in the secondary diaphragm housing mates with the main body casting and reassemble the housing and choke to the m
17. r position on the intake manifold 3 Place the carburetor on top of the flange gasket on the manifold Install the hold down nuts and snug down progressively in a crisscross pattern 60 80 6 as shown in Figure 5 ENGINE Figure 5 Carburetor hold down nut torque sequence WARNING Overtightening may result in a warped or cracked carburetor throttle body 4 Before connecting the linkage operate the throttle lever to assure the correct travel no sticking or binding by opening to wide open throttle and back to closed throttle several times Correct any sticking or binding conditions before proceeding WARNING Any sticking binding or other interference in the throttle linkage could result in uncontrolled engine speed This could result in engine damage or personal injury 5 Reconnect the throttle and transmission kickdown linkage and throttle return spring Holley P N 20 89 Operate the carburetor throttle lever by hand to assure the correct travel no sticking or binding by opening to wide open throttle and back to closed throttle several times Correct any sticking or binding conditions before proceeding NOTE With the engine turned off have an assistant slowly press the accelerator pedal to the floor while you watch the throttle for any sticking or binding Correct any sticking or binding conditions before proceeding Also ensure that you are reaching full throttle Many performance problems a
18. re traced to partial throttle openings from improperly adjusted linkage Secondaries will not open mechanically during this procedure FUEL BOWL VENTS TIMED SPARK VACUUM SOURCE TO DISTRIBUTOR VACUUM ADVANCE FUEL LEVEL FUEL LEVEL ADJUSTING NUT N SIGHT PLUG FUEL LEVEL ees FUEL LEVEL SIGHT PLUG g gt g ADJUSTING NUT SECONDARY FUEL INLET FITTING PRIMARY SECONDARY b gt FUEL INLET FUEL BOWL y Mo FITTING POWER BRAKE PRIMARY OR PCV VACUUM PORT FUEL BOWL CONDAR DIAPHRAGM CHOKE FRESH HOUSING AIR INTAKE POSITIVE IDLE MIXTURE SCREW BLOCK CHOKE TERMINAL ONE EACH SIDE MUST HAVE 12 NEGATIVE CHOKE FRESH CHOKE TERMINAL AIR VACUUM LINE MUST BE GROUNDED Figure 6 Reconnect the appropriate vacuum hoses to the carburetor noting the correct fitting from Figure 6 and 7 Replace any cracked or dry rotted hoses at this time to prevent any vacuum leaks A full manifold vacuum source the front of the throttle body provides vacuum for proper operation of the air cleaner the pump diverter valve if equipped AC Cruise and or the temperature sensing valve If vacuum for more than one component is needed use small plastic vacuum 5 available at most automotive stores The timed spark fitting in the choke side of the primary metering block provides vacuum for the operation of the distributor vacuum advance Connect the hose to the distributor spark delay valve
19. signed to work with ANY other automatic overdrive transmission 1 Remove the throttle cable ball and automatic transmission kickdown stud if any from the original carburetor and mount these in similar locations on the Holley throttle lever If the original throttle cable is too large a new throttle ball or stud is needed Holley P N 20 2 or 20 38 NOTE For proper adjustment of the GM automatic kickdown linkage refer to the appropriate GM service manual for your application CHOKE ADJUSTMENT IMPORTANT Your Holley carburetor has been factory wet flowed and calibrated The out of the box settings should be very close for all adjustments The following tuning section is included ONLY to aid you in fine tuning adjustments 1 You can control the choke operation by rotating the choke cap If the choke comes off too soon rotate the cap counterclockwise one notch at a time until the choke operation 15 satisfactory If the choke comes off too late rotate the cap clockwise one notch at a time until the choke operation is satisfactory The choke setting from the factory is on index or at center position After making the final adjustments start the engine and make sure the choke plate opens completely A Achoke that comes off too soon could exhibit one or more of the following symptoms stalling surging backfiring stumbles or poor vehicle driveability when the vehicle is cold B Achoke that comes off too late could exh
20. sions These vehicles often idle at 2000 rpm approx 6 0 Hg At this point the main nozzles are starting to feed and richen the mixture supplied by the power valve and the engine will probably load up To correct this problem install a 45 or 35 power valve If the engine has a manifold vacuum of 12 Hg or less a good way to determine power valve size is take the manifold vacuum at idle and divide that number by two The answer is the power valve size This will provide idling and proper fuel flow under wide open throttle conditions when manifold vacuums seldom rise above 1 Hg 13 CARBURETOR SPECIFICATIONS CARBURETOR PRIMARY SECONDARY PUMP PRIMARY SECONDARY SECONDARY METERING METERING DISCHARGE POWER POWER DIAPHRAGM JET JETS NOZZLE VALVE VALVE SPRING 0 80531 0 040 PINK Holley Performance Products Inc 1801 Russellville Road Bowling Green KY 42101 Technical Service 1 270 781 9741 Fax 1 270 781 9772 For online help please refer to the Tech Service section of our website www holley com 2000 Holley Performance Products Inc All rights reserved 199R10174 1 Revision Date 8 25 11 14
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