I am attaching the fuel line to the fuel tank and I have a question. The connector doesn't screw in flush to the tank. If you look at the first picture you can see where the brass is shinny. This marks the extent to where this attachment can be screwed on to the gas tank. My question is does this attachment need to be screwed all the way flush to the tank in order to make a seal tight enough to prevent fuel leakage? I don't want to strip it!