FLOAT LEVEL

This illustration show how to set the float level on the BB-1 carburetor. The gauge that is shown is not available, but using a metal ruler to do the same measurement is as good as anything.

1. Remove the carburetor from the engine

2. Separate the float chamber from the throttle valve body

3. Hold the float needle valve in the closed position, and meaasure the distance from the top of the float chamber (gasket removed) to the top of the float. This distance should be 3/64”. Adjustment of the float level can be made by bending only the vertical lip of the float lever.

Carter BB-1 Float Level Adjustment

Adjusting the float level in the Carter BB-1 updraft carburetor is essential for ensuring optimal fuel delivery to the engine. An incorrect float level can lead to issues like flooding, poor performance, or reduced fuel efficiency. Here's how you can adjust the float level:

Safety First: Always work in a well-ventilated area, away from open flames or sparks. Ensure the engine is turned off and cool to touch.

1. Remove the Carburetor Top:
   • Disconnect the fuel line from the carburetor.
   • Loosen and remove the screws or fasteners holding the top (or float chamber lid) of the carburetor in place.
   • Carefully lift off the top, ensuring you don't damage the gasket. If the gasket is damaged, it will need replacement.
2. Inspect the Float:
   • Before adjusting, check the float for any signs of damage or fuel inside. If the float has fuel inside, it's leaking and needs replacement.
3. Measure the Float Level:
   • With the top removed, invert the lid so the float hangs down.
   • Measure the distance between the float and the gasket surface of the carburetor top. The specifications for the float level will be found in the service manual specific to your engine or vehicle model. Often, this measurement is made using a ruler or specialized float gauge. 1/32" to 1/16".
4. Adjust the Float Level:
   • The float level is adjusted by bending the small metal tab where the float needle connects.
   • If the float level is too high (meaning the float is too close to the gasket surface), gently bend the tab downward. This will lower the float when the lid is reinstalled.
   • If the float level is too low (meaning the float is too far from the gasket surface), bend the tab upward. This will raise the float level when the lid is reinstalled.
5. Recheck the Float Level:
   • After making your adjustments, measure the float level again to ensure it matches the recommended specifications.
6. Reassemble the Carburetor:
   • Ensure the gasket is in good condition and properly seated.
   • Carefully position the carburetor top back onto the base, ensuring the float is not obstructed or pinched.
   • Secure the top using the screws or fasteners. Do not overtighten; this can warp the top or damage the gasket.
   • Reconnect the fuel line.
7. Final Check:
   • Start the engine and let it run for a few minutes. Check for any signs of flooding, dripping fuel, or other irregularities in engine performance.
   • If issues persist, you may need to recheck the float level or inspect for other potential problems.