I had the issue about 8 years ago and found the solution on one of the internet sites. To this day it has been effective. Unfortunately, I didn’t write down the product and I can’t find it now.
Anyway, cork, fuel proof dope, etc. are only temporary solutions. Ethanol dissolves them all in time, just like it dissolved the lacquer on the cork OEM floats.
I bought an ethanol safe synthetic rubber carb float. It was about the same size as the OEM tank float and it still works fine.
Maybe a google search will dig it up. My memory ain’t too good, but I seem to recall it was a Sierra part. Sorry I can’t help further…