How to Adjust an Edelbrock 4 Barrel Carburetorby Helen Jody Lin
The Edelbrock 4-Barrel carburetor is a mechanism that delivers fuel to the engine and, when mixed with air, creates small explosions in the four cylinder chambers of the combustion engine. While most carburetors are made with one or two barrels, the 4-Barrel carburetor is primarily equipped in high-performance vehicles. Due to weather and age, carburetors can become unbalanced and out of tune. Using a flat-head screwdriver, you can adjust the speed of the fuel-delivery system to provide a smooth driving experience.
Park the vehicle away from traffic and engage the emergency brake for added security. Start the engine and let it warm up for several minutes to allow the choke to fully open.
Consult your vehicle and carburetor owner's manuals to find the recommended revolutions per minute (RPM) speed for your particular model. Most high performance vehicles with an Edelbrock 4-Barrel carburetor will need to run around 800 to 900 RPMs in the idle mode.
Locate the carburetor idle screw near the front of the unit, the side closest to you. With a flat-head screwdriver, turn the screw counterclockwise to decrease RPM speed and clockwise to increase the speed.
Listen for the engine noise. Adjust the idle screw until your carburetor makes a low, humming noise. If you begin to hear a higher pitch noise, adjust the screw the other direction until you find a nice engine pitch. Reconfirm with the recommended level by looking at the RPM levels on your dash.
Wait several minutes to make sure the carburetor does not continue to fluctuate between speeds. If the speed continues to increase and decrease while idle, it may be time to replace your carburetor. If not, you are safe to drive your vehicle.
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