Things You'll Need:
- Screwdriver Vacuum gauge Tachometer gauge Gloves
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Step 1
Run the engine until the average operating temperature has been reached. Place the transmission in park on a level, flat surface that is well lighted and ventilated during the tuning of the carburetor. Open the hood to access the engine. Remove the air filter and cover by loosening the wing nut that secures the air filter and housing to the top of the carburetor. Inspect the carburetor to be sure that the choke is completely open. This is when the carburetor's butterfly valves are open. These valves can restrict the amount of air into the carburetor during start-up, causing a fuel-rich mixture that is easier to ignite. Closed valves mean the choke is closed.
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Step 2
Connect a tachometer gauge to the negative side of the ignition coil and to a good ground. The gauge will be used to show the different RPM that the engine is building to prior to shifting or during acceleration. Having the proper fuel mixture at each step of the fuel delivery will improve the response the engine gives during operation. All three stages of the carburetor must be tuned to get the best performance. Connect a vacuum gauge to the vacuum lines going into the intake manifold. Use a T-adapter and the existing connectors to utilize the vacuum gauge for this purpose.
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Step 3
With the engine running, locate on the front of the carburetor two screws that can be adjusted in or out. The adjustment alters the amount of fuel going into the engine at idle, and can be set for a richer or leaner burn condition. Set the idle to burn on a most lean condition without causing the engine to sputter. Tuning the idle in this way allows for the highest amount of vacuum pressure to be built up prior to the activation of the accelerator pump. More vacuum means better response when the gas pedal is used and the carburetor goes off its idle setting. Set the screws to produce the highest amount of vacuum at idle. An engine should turn around 900 RPM; set the idle so that it makes the most vacuum pressure and idles smoothly within 100 RPM of the 900 RPM standard.
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Step 4
Once the idle has been set correctly, the metering of the primary and secondary fuel delivery systems will begin. Adjust the metering jets with a screwdriver so that the carburetor injects enough fuel to create equal vacuum pressures during use. Press the accelerator hard enough to rev the engine up to 6,000 RPM. Watch the pressure of the vacuum as the tachometer needle goes up through the RPM levels. If a change in the pressure is noticed, an adjustment in fuel delivery is needed to eliminate this condition. The carburetor should deliver enough fuel without causing a lag in response or a sputtering from lack of fuel. Set correctly using the idle adjustment and the correct metering jets, An Edlebrock Performer carburetor can supply enough fuel into an equipped engine to operate well for daily driving or put under harsh, race conditions.
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Step 5
Remove the tachometer and vacuum gauge from the engine compartment, and reconnect the vacuum hose to the intake manifold. Replace the air filter and housing to the top of the carburetor inlet, and secure with the wing nut fastener. Close the hood and test drive. The engine should respond crisply when the accelerator is depressed, and never lag under pressure from the driver after taking the correct steps to tune the carburetor to the engine properly.
