RE: McCoy diesels
I am not sure they used a gasket on them. If the fit is fairly close the leak would be slight, not enough to be a problem, as the engine would run out of fuel fairly fast when running anyway. I haven't taken it apart yet to clean and lube it for running, so I can't tell if there is a gasket in there or not for the fuel tank.
Yeah sorry, I couldn't see anything wrong with your engine as to why to didn't want to run. Beats me.