Home Tips & Tricks How to Adjust a Two-Barrel Rochester Carburetor

How to Adjust a Two-Barrel Rochester Carburetor


The two-barrel Rochester carburetor is designed with two adjustment screws, located in the front of the carburetor near the base. Adjusting the carburetor is fairly simple and the adjustment screws are easy to access. The idle fuel mixture screw on the left side and the idle speed screw on the right side should be adjusted to read the same on the vacuum gauge at the highest readings possible to get the best performance from your engine.

Things You’ll Need: Screwdriver, Vacuum gauge


  • Locate the two idle adjustment screws in the front of the two-barrel Rochester carburetor and turn both screws clockwise with a screwdriver until they are completely closed. Be careful not to over-tighten the screws. Turn the adjustment screws back, counterclockwise one and a half turns with the screwdriver to use as a starting point for your adjustments. Start the engine and let it warm up for about five minutes.