the float isnt/shouldnt be the problem here (yes, even with it not shutting off). THe floats are meant to "stop" fuel from flowing into the bowls from the gravity feed fuel system.
I would recheck the floats, and make sure the valve set (the spring loaded pin that controls the float action) is still good. The fuel should come up, and the float should rise up freely till it shuts off the fuel on it's own. If the float doesn't move freely, that would allow fuel to keep coming into the bowls and over filling.
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Charles Gallant