No, fuel line aint too large. When I first started in glow aircraft, a guy in the club with years experience told me what to get. I got 10 feet of the stuff. It fits snuggly on all the needle valve fittings and the tubes that are on the fuel tank. The fuel line don't come off of those. It don't happen all the time but at least half the time. Could be that the fuel nipple on my hand pump is crappy. In any event, the trick works for me every time.

Dave...