If cork float is in decent shape coating with thinned epoxy or super glue
said to be doable and satisfactory. Sometimes, and this may be the case here,
the float has deteriorated and become unusable. Replacing with a modified
Mercury closed cell float is one alternative to consider.
I believe all of the Tillotson AJ series gravity feed (tank on motor)carburetors
use the same float and float rod. The closed cell float is made for a separate
tank and fuel pump pressure feed carburetor but can be modified to work with
the older carburetors.