PERFORMER SERIES ® & THUNDER SERIES AVS ® CARBURETOR © 2005 Edelbrock Corp. OWNERS MANUAL Edelbrock Corporation 2700 California Street Torrance, CA 90503 Tech Line: 1-800-416-8628 7am-5pm PST, M-F www.edelbrock.com All parts not legal for sale or use on pollution controlled vehicles. Rev.
INTRODUCTION Your Edelbrock Performer Series carburetor was calibrated using Edelbrock Performer, Performer RPM, and Torker II Power Packages. The carburetor metering was developed on Edelbrock engine dynamometers, chassis rolls, and a variety of development vehicles. Although in most applications you will not need to recalibrate your carburetor, you may wish to change the factory calibration to best meet any unique needs of your engine.
SECTION 1: THEORY OF OPERATION BASIC ENGINE REQUIREMENTS The spark-ignition 4-cycle engine burns a mixture of AIR and FUEL. The air is controlled by the driver’s operation of the throttle. The fuel is mixed with the incoming air by the carburetor. The Ratio of AIR to FUEL is the AIR/FUEL Ratio (A/F). This is a ratio by WEIGHT; if 12 pounds of Air are combined with 1 pound of Fuel the A/F is 12:1, or more commonly, A/F = 12.
Fuel is drawn through the Idle System (Figure 2) by the intake manifold vacuum that is communicated at the Idle Screw Port (8) and Transfer Slot (7). Fuel in the bowl passes through the Primary Main Jet and Metering Rod Restriction (1) and into the Primary Well (2). The fuel for the Idle System is drawn through the restriction at the end of the Idle Jet (3) - a brass tube - and flows up the tube to the location of the 1st Idle Air Bleed (4) - a brass restrictor - where air is mixed with the liquid fuel.
Secondary Main System: The Secondary Main System (Figure 5) delivers fuel only when the secondary throttle blades and air valve are open. It ensures that fuel delivery varies with air flow. The Secondary Throttles (1) begin to open when the Primaries are about 65% open. The Primary and Secondary Throttles arrive at the WOT stop at the same time. Air flow through the Secondary side is controlled by Air Valves (2). These valves are located in the secondary bores above the throttle blades.
Pump System: When the throttle is opened rapidly, the air flow through the engine will increase immediately. The fuel, since it is much heavier than the air, will “lag” behind. This contributes to a temporary lean A/F condition. Regardless of cause, a solution is to temporarily enrichen the A/F Ratio by mechanically pumping a small quantity of fuel into the throat of the carburetor (Figure 7).
To help you calibrate your carburetor, a CALIBRATION REFERENCE CHART has been designed for each model of the Edelbrock Performer Series carburetor. These charts (pages 10-19) each consist of two sections: A Calibration Table and a Rod/Jet Reference Chart. After reading the Calibration procedures, the next step in calibrating your carburetor is to look at the Calibration Table for your model carburetor. Determine if you would like to go richer or leaner in the Cruise Mode and do the same for the Power Mode.
Long Duration Camshaft If the engine has a fairly radical camshaft it may require an excessive amount of throttle opening for idle and/or have low idle vacuum levels. Either condition can lead to poor levels of adjustability and erratic idles. • Another fix for the above condition is to run as much spark advance as possible at idle. If the distributor is fitted with a vacuum advance unit, connect it directly to manifold vacuum.
CALIBRATING THE POWER MODE STAGING The Step-Up function, which moves the Metering Rod to the Power Mode, is controlled by the Step-Up Spring. The base calibration has a spring which “stages” rich at 5" Hg. If your vehicle has a mid-throttle driveability problem that is encountered as the throttle is gradually opened, but then goes away upon further opening, it may be possible to eliminate the lean spot by using a stronger Step-Up Spring.
The length of time during which the choke will stay closed is determined by the position of the choke cap. As the choke cap is turned clockwise the choke will stay closed longer. To properly set the choke loosen the chock housing retaining screws then turn the choke cap to the leanest notch on the choke housing and run the engine until normal operating temperature is reached. With the engine running, slowly turn the choke cap clockwise until the choke valve begins to close.
#1403 / 1404 Calibration Reference Chart / Primary Metering Step 1 Select the combination of Cruise Mode and Power Mode fuel-metering stages desired for your calibration. Normal calibration changes will be within the shaded diagonal area. That is, Cruise and Power mode changes should be in the same direction (either richer or leaner) and usually by the same amount. Step 2 Find the number that is nearest your desired combination. This is your Calibration Reference Number.
#1405 Calibration Reference Chart / Primary Metering Step 1 Select the combination of Cruise Mode and Power Mode fuel-metering stages desired for your calibration. Normal calibration changes will be within the shaded diagonal area. That is, Cruise and Power mode changes should be in the same direction (either richer or leaner) and usually by the same amount. Step 2 Find the number that is nearest your desired combination. This is your Calibration Reference Number.
#1406 Calibration Reference Chart / Primary Metering Step 1 Select the combination of Cruise Mode and Power Mode fuel-metering stages desired for your calibration. Normal calibration changes will be within the shaded diagonal area. That is, Cruise and Power mode changes should be in the same direction (either richer or leaner) and usually by the same amount. Step 2 Find the number that is nearest your desired combination. This is your Calibration Reference Number.
#1407 / #1410 Calibration Reference Chart / Primary Metering Step 1 Select the combination of Cruise Mode and Power Mode fuel-metering stages desired for your calibration. Normal calibration changes will be within the shaded diagonal area. That is, Cruise and Power mode changes should be in the same direction (either richer or leaner) and usually by the same amount. Step 2 Find the number that is nearest your desired combination. This is your Calibration Reference Number.
#1409 Calibration Reference Chart / Primary Metering Step 1 Select the combination of Cruise Mode and Power Mode fuel-metering stages desired for your calibration. Normal calibration changes will be within the shaded diagonal area. That is, Cruise and Power mode changes should be in the same direction (either richer or leaner) and usually by the same amount. Step 2 Find the number that is nearest your desired combination. This is your Calibration Reference Number.
#1411 Calibration Reference Chart / Primary Metering Step 1 Select the combination of Cruise Mode and Power Mode fuel-metering stages desired for your calibration. Normal calibration changes will be within the shaded diagonal area. That is, Cruise and Power mode changes should be in the same direction (either richer or leaner) and usually by the same amount. Step 2 Find the number that is nearest your desired combination. This is your Calibration Reference Number.
#1412 & #1413 Calibration Reference Chart / Primary Metering Step 1 Select the combination of Cruise Mode and Power Mode fuel-metering stages desired for your calibration. Normal calibration changes will be within the shaded diagonal area. That is, Cruise and Power mode changes should be in the same direction (either richer or leaner) and usually by the same amount. Step 2 Find the number that is nearest your desired combination. This is your Calibration Reference Number.
#1805 / #1806 Calibration Reference Chart / Primary Metering Step 1 Select the combination of Cruise Mode and Power Mode fuel-metering stages desired for your calibration. Normal calibration changes will be within the shaded diagonal area. That is, Cruise and Power mode changes should be in the same direction (either richer or leaner) and usually by the same amount. Step 2 Find the number that is nearest your desired combination. This is your Calibration Reference Number.
#1812 / #1813 Calibration Reference Chart / Primary Metering Step 1 Select the combination of Cruise Mode and Power Mode fuel-metering stages desired for your calibration. Normal calibration changes will be within the shaded diagonal area. That is, Cruise and Power mode changes should be in the same direction (either richer or leaner) and usually by the same amount. Step 2 Find the number that is nearest your desired combination. This is your Calibration Reference Number.
#1825 / #1826 Calibration Reference Chart / Primary Metering Step 1 Select the combination of Cruise Mode and Power Mode fuel-metering stages desired for your calibration. Normal calibration changes will be within the shaded diagonal area. That is, Cruise and Power mode changes should be in the same direction (either richer or leaner) and usually by the same amount. Step 2 Find the number that is nearest your desired combination. This is your Calibration Reference Number.
Exploded View of Edelbrock Performer Series Carburetor 1 1 2 6 2 6 4 3 3 4 16 22 5 5 24 17 16 18 8 14 21 19 17a 28 15 20 23 23 7 27 27 25 25 26 26 ITEM DESCRIPTION 1. 2. 3. 4. 5. 6. 7. 8. 9. 9a. Step-up piston cover screws (2) Step-up piston cover plates (2) Step-up pistons (2) Step-up (metering) rods (2) Step-up piston springs (2) Step-up rod retainer springs (2) Pin springs (small) (3) Choke connector rod & lever* Choke piston housing* Choke piston housing seal* 20 9b.
39 39 40 40 31 41 45 41 44 44 31 42 45 32 29 34 43 43 33 32 35 36 10a 10 37 38 8 33 30 49 47 11 13 12 9 9a 50 9b 52 48 51 46 46 27. 28. 29. 30. 31. 32. 33. 34. 35. Needle & seat assemblies (2) Airhorn gasket Pump plunger assembly Pump plunger spring Primary cluster screws (4) Primary venturi boosters (2) Venturi booster gaskets (2) Pump jet housing screws (2) Pump jet housing *Electric choke models 1406, 1409, 1410, &1411 36. 37. 38. 39. 40. 41. 42. 43. 44.
Troubleshooting Chart POSSIBLE SOLUTION Check for air leaks. Make sure carburetor and manifold gaskets seal properly. All outlets must be plugged or connected. Check ignition system. Replace parts as necessary. Adjust timing to proper specifications. Check choke adjustment. See page 8. Change carburetor fuel filter and/or in-line fuel filter. Too lean. See Tuning Procedure. Check float level and drop. See page 8. Check idle mixture screw adjustment. See page 6. Too rich. See Tuning Procedure.
Troubleshooting Information Dirt/metal shavings between the needle and seat or a “sticking float”: To correct either of these problems, lightly tap the carburetor fuel inlet area with the handle of a screwdriver. If flooding continues, pinch the fuel line (if possible). Start the engine and let it run until it stops. Release line and restart engine. If flooding persists examine the needles, seats, float level, and float drop. Adjust or replace parts if necessary.
Notes: 24
Notes: 25
