On vehicles which are infrequently started; the float sticks because of the residue from evaporated fuel which acts like a glue. GENERALLY (not always), fresh fuel will dissolve the "glue" and the float only sticks for a few minutes.
This will occur on a used, rebuilt, or new carburetor.
The solution is easy. Start the engine sufficiently often to not allow the fuel to evaporate out of the carburetor bowl.
Jon.
