Need to back the thread up for a sec- nonstop is right about the stopper. If you are using a dubro tank and using the black one that came with it, it will work for a while but over time it swells and deteriorates. Eventually it will break up and bits of it will contaminate your fuel. At some point your engine will not work right and you'll have to clean out the carb. I've seen it on multiple occassions.

Dave