the fuel tank cover?
if so, i used west g-flex to bond small chunks of starboard under the holes. i had small pieces of pressure treated pine and they broke down after a few years. starboard has held up great and can apply more torque than with wood
http://www.westmarine.com/buy/west-s...dener--9223132
this is the stuff, but they make a thickened that is like toothpaste, use it