How to Adjust a Carburetor

A carburetor is a crucial part of any car's engine. The carburetor is used to mix gas and air together, aiding the combustion process. Parts of a carburetor can become contaminated by all kinds of environmental filth, such as dirt, grass or even small sticks. It's important for a car owner to clean and adjust a carburetors regularly to ensure the engine functions as efficiently as possible.

Adjust the Idle Speed and Mixture of Your Carburetor

  • Turn off your car's engine and lift the hood.

  • Locate the air filter and remove it. Locate and remove the accompanying air cartridge.

  • Turn the "idle mixture screw" clockwise. Stop turning it once the registering needle reaches the seat.

  • Turn the same screw back counterclockwise. Complete one and a half rotations. If your vehicle has a carburetor with a main jet adjustment located at the bottom of the float bowl, you'll need to turn that screw counterclockwise until it touches the emulsion tube's seat.

  • Secure the air filter and cartridge back in their original positions.

  • Restart your engine.

  • Allow the engine to run for a few minutes. This will raise the engine's temperature. Run the engine at half throttle.

  • Locate the "idle mixture screw." Turn it clockwise. Once the engine has slowed, turn the screw back half way again.

  • Set an aluminum-cylinder engine to run at 1,750 RPM. An engine that features a cylinder sleeve made of cast-iron should be set to run at 1,200 RPM.

Adjust a Carburetor's Choke Linkage

  • Remove the air filter and cartridge from your engine.

  • Find the choke lever. It will either be found on the engine itself or within the remote speed controls.

  • Change the settings to "fast" or "high," as described on your equipment.

  • Relax the mounting brackets around the cable casings. You'll want the casings to move freely.

  • Adjust the cable casings until the engine's choke is closed.

  • Screw the cable mounting back into place.

  • Inspect the control lever's motion. Continue these adjustments until the choke linkage has been set to your liking.