How to Identify Carburetor Adjustment Screws

Identifying the carburetor adjustment screws is a fairly simple job that can be done in just a few minutes. There are generally two adjustment screws on the carburetor, an air speed adjustment and a fuel mixture adjustment. The adjustment screws are either both in the front of the carburetor barrel or one on each side. If you have an exterior choke rod leading from the intake manifold to the carburetor, the air speed adjustment screw will be on the barrel next to the choke rod.

  • Park the vehicle away from traffic. Turn off the engine and set the emergency brake. Raise the hood and allow the engine to cool. Remove the air cleaner assembly which covers the carburetor by removing the wing nut from the top. Lift the air cleaner off the carburetor and set it aside.

  • Look at the bottom of the carburetor barrel, in the front and on both sides. Generally, there are two adjustment screws, either in front of the carburetor barrel or one on each side.

  • Locate the two flat head screws which have standard screwdriver slots. These carburetor adjustment screws will have springs behind their heads to provide tension for more precise adjustment.