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How to Free Up the Float in a Carburetor

by Rachel Steffan

You're driving along when suddenly, your vehicle chokes and sputters to a halt, starved of fuel -- or you are driving along just fine and suddenly, your exhaust system begins to belch black smoke. When you turn off the engine and look under the hood, you find fuel dripping from the carburetor throat. Both problems may be caused by a stuck carburetor float. Fortunately, you can take steps to get the carburetor working again temporarily, until you can open up the carburetor and fix the float permanently.

Temporary Repair

Open the hood and locate the carburetor body. Tap the top of the carburetor gently but firmly with a small hammer or screwdriver handle. Tap the bowl of the carburetor firmly. This may loosen a stuck float valve, allowing the float to work properly until you can fix the problem permanently.

Remove the drain plug at the bottom of the carburetor bowl with a wrench or a pair of locking pliers if the problem persists. Place a pan under the carburetor to catch the draining fuel. The pressure of the fuel flowing through the carburetor should free the float.

Remove the drain plug in the carburetor throat. Spray carburetor cleaner into the throat and let it drip out of the carburetor bowl drain with the fuel. The carburetor cleaner will dissolve dirt and deposits blocking the float's movement or clogging the float needle.

Replace the drain plugs. If the carburetor was flooded, let the vehicle sit for an hour or two before starting it.

Permanent Repair

Turn off the flow of fuel to the carburetor by closing a valve or clamping the line with vise grips. Disconnect the negative battery terminal.

Remove the drain plug on the carburetor bowl and let the fuel drain into a container. Loosen the bolts holding the carburetor bowl to the carburetor body. Remove the bowl, exposing the carburetor float.

Place the point of a pick or very small Phillips screwdriver against the edge of the pin holding the hinges of the carburetor float. Tap the pick or screwdriver gently with a small hammer to push the end of the pin free. Grasp the end of the pin with a pair of pliers and carefully pull it lose from the float's hinges. Remove the float. Check that the needle valve is sitting in the notch on the float. If it's not with the float, retrieve it from the needle seat. Inspect the needle valve for wear and replace it if necessary.

Spray the float, pin and needle valve liberally with carburetor cleaner and scrub them with a toothbrush or lint-free cloth. Clean the valve seat with a cotton swab soaked with carburetor cleaner. Examine the float for holes or other damage and replace it if necessary.

Place the needle valve in the notch on the float and position the float correctly against the carburetor body. Replace the pin that holds the float hinge together and tap it carefully into place with the hammer.

Check the gasket on the carburetor bowl and replace it if necessary. Put the bowl on the carburetor body and tighten the bolts that hold it in position. Restart the flow of fuel to the carburetor and check for leaks. Reconnect the battery.

Tip

  • Dirty fuel is a prime cause of stuck carburetor float valves and needles. Check and replace the fuel filter if a stuck float is a recurring problem.

Warning

  • Fire is always a danger when dealing with the fuel system. Never smoke when working on the carburetor.

Items you will need

About the Author

Based in central Missouri, Rachel Steffan has been writing since 2005. She has contributed to several online publications, specializing in sustainable agriculture, food, health and nutrition. Steffan holds a Bachelor of Science in agriculture from Truman State University.

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Photo Credits

  • vieux carburateur image by olivier lhommais from Fotolia.com