I am working on a 1973 Evinrude 2hp Mate. This motor has the built-in metal fuel tank. I have NOT been able to get the fuel cap to fully seal so as you motor along, gas spills out onto the tank, etc. I have tried everything I can think of. I am thinking the problem might stem from the fact that, over time, the metal lip of the tank gets mis-shappen so no seal can occur. I have tried 4 different fuel caps with various rubber gaskets, o-rings, cork gaskets, etc. but cannot find a solution. Does anyone have experience with how to resolve this?