There have been reported problems with the fuel tank rubber seal not holding up and disloging resulting in all the fuel draining out the bottom of the tank - not a good idea.
I fabricated a new washer on the metal lathe with an internal bevel to seat against the head of the valve in order that the rubber seal will be sandwiched between two washers. Now there is no way for the seal and valve to drop out the bottom of the tank.
