Allan,
Did that usher fuel cap have a 2" diameter? Also what did the hole look like? Is it just a aluminum ring in the wing? I need to replace my caps as they don't seal anymore but I don't want to replace the receptacle in the wing. Does anyone out there have any ideas? The current caps "seal" by exerting outward on a rubber grommet. The grommet has since gotten hard so now it doesn't seal anymore. I would be happy with a similar setup if it just sealed!