Fixing stuck needle valves - Stromberg carbs

[lotuar]

This is an old thread, but I’d like to add some additional observations.

I believe there could be some additional causes for fuel overflowing when the carbs have been empty for some time. (This being a rather dangerous situation in a closed garage - or elsewhere)

The floats seem to “catch”. Rapping the carbs with a small hammer or something similar often will break them loose and all is then well. …but sometimes not.

One possible cause is the dimple that forms on the float arm where it presses on the needle valve. The float drops and the needle valve lodges in that dimple.

In my case, where I would normally look at these wear patterns to try to put things back as they were, this might not be the best thing here. Swap the front and rear floats to provide a ”virgin” surface for the needle valve.

Another possible cause is the corrosion that occurs in the bottom of the bowl where the float rests when it’s empty. Capillary action would cause the fuel to remain there longer than elsewhere, causing the corrosion.

Combine this with roughness on the edge of the float that contacts that corrosion, and it sticks.

Clean, smooth and polish the bottom of the bowl, as well as the bottom edge of the float.

It worked for me.

-Doug