ORIGINAL: CGRetired

NO! Don't "tighten that screw real good". It should be snug, but not as tight as you can get it. Doing that will split the neck of most fuel tanks.

I've read that the best method is to put the thing together, then turn the compressing screw in until it begins... BEGINS... to compress and seal the bung in the neck of the tank. It should be snug, but not tight. It should turn slightly, under pressure from twisting by your fingers, but that's just about it. Any more and it will more than likely split the neck of the fuel tank.

I will find the link that describes this to prevent what I expect to be some incoming flack about this. But, I think many of the experts here on RCU will verify that it should not be tightened beyond being snug, enough to slighly expand the bung and seal off the tank, but not tight enough so you cannot turn the bung in the neck. As I said, snug, but not turn easily, but turn with a little effort. How much is that? I don't know, but I do know it should not be so tight that it will not turn.

CGr.