Todays fuel (especially that containing alcohol) leaves a very sticky residue when it evaporates. The residue tends to be re-absorbed when fresh gasoline comes into the bowl.

The float could be temporarily sticking because of stickiness on the edge of the float arm where it contacts the float hanger. Make sure there is plenty of clearance at this point.

Jon.

Good carburetion is fuelish hot air
The most expensive carburetor is the wrong one you attempt to modify.
If you truly believe "one size fits all," try walking a mile in your spouse's shoes!
The Carburetor Shop