How to Adjust Carburetor Floats

by Carl Pruit

Your vehicles carburetor float is a vital part of the fuel system. It is the gauge which tells your carburetor how much fuel it needs and when it needs it. As you depress the gas pedal, fuel is sucked out of the carburetor reservoir which causes the carburetor float to drop. As the float drops, it opens the needle valve and allows more fuel to enter the reservoir. When you let up on the gas pedal, you decrease the demand for fuel which has a chain reaction. Fuel is no longer sucked out, which causes the float to return to its normal position and closes the needle valve, shutting off the flow of fuel until it is needed again. All of this can happen within fractions of a second.

Remove the linkage from your carburetor with a pair of needle-nose pliers and disconnect the vacuum hoses leading to your carburetor. Mark the parts to remember how they were assembled for later reference.

Remove the bolts that are holding the carburetor to the engine and take the carburetor out of the engine. Lay the carburetor out on top of your work space.

Locate the fuel reservoir tank on your carburetor and remove the bowl by unscrewing it from the top of the reservoir with a screwdriver. Carefully pour the fuel that is in the reservoir into a gas can.

Turn the carburetor upside down so that you are looking at the float from the bottom. With the float seated flat against the needle valve, use your fuel level gauge and measure from the bottom of the float to the mating edge or bottom of the existing reservoir bowl with the bottom off. Your float should be set at 16 mm.

Verify that your float is at least 16mm from the bottom to the edge of the reservoir bowl. If it is not, use the needle-nose pliers to carefully bend the float tabs and recheck the measurement. Do this until the float is at the correct setting.

Reattach the float reservoir bowl to the top cover with screws and then place the carburetor back on the engine. Secure the carburetor to the engine with bolts. Reattach all the vacuum hoses and linkage to the carburetor.

Test the carburetor float adjustment by starting the engine and observing how it idles.

Tip

  • check *Cover your work surface with plastic or newspaper so that the surface of your workspace does not get ruined by gasoline.

Warning

  • close Remember that gasoline is highly flammable. Do not work anywhere that is closed in or near any flame source.

Items you will need

About the Author

Carl Pruit has been a freelance writer since 2005, specializing in service journalism and travel. His work has appeared on various websites. Born and raised in California, Pruit attended Contra Costa Community College in San Pablo, Calif. and received an associate degree in the administration of justice.