i have been breaking down recently very often since i put bio diesel in. and had to keep pulling over to blow the fuel pipe coming from the tank to pump. so i have had enough and run tank till near empty and opened up the top of the tank to find that there was a milk bottle top metal in my fuel tank and was trying to get sucked up all the time and blocking the pipe. so guessing the bio diesel had loosened it off on the tank as it was a farmer who owned before me you live and you learn.

Farmers used to run on a mix of derv and goldtop..

who knew hahahaha.

I had a similar problem, but never found the lid