The old coating that you see on both tank and carburetor cork floats is shellac. The old shellac is not compatible with ethanol in modern fuel and degrades causing carburetor problems.
As others have stated, if the old cork is in good condition, then it can be scuff sanded and recoated. It is not necessary to remove all of the shellac because the new coating will seal it in against the fuel. Additionally, too much sanding will make the float volume less than original. I like to use two coats of dollar store original super glue with plenty of curing time before exposure to fuel mix.
For tank floats that are degraded, it’s very easy to make a nice new float. Just buy oversize cork stoppers at the local hardware store, center drill them and use a hand drill in a vise as a poor man’s lathe. I have used a paint stirring stick with sandpaper attached on the end to shape the float as it spins. Once setup it’s a good time to make some extras.
The last 90-degree bend in the float wire can be heated before bending straight to accommodate the new float. after sliding the new finished float on the wire, bend the wire back to 90-degrees without the use of heat.
Improvise-Adapt-Overcome
