From what I've read here, the suggested fix is to put a loop in each of your overflow tubes, and put a small amount fluid (oil?, can't remember which kind now) into the overflow tubes, just enough to fill the bottom part of the loop. This will help prevent gasoline from evaporating through the overflow tubes, and will flush right out if you have a stuck float issue.
I'm sure someone will chime in here any moment now with what fluid they use...