I'm trying to drain the fuel tank on my 2007 500, and I can't move the petcock switch to the Prime position. It sits too close to the lower rim of the fuel tank, and it's blocked from turning all the way up to Prime. If I try to force it, a little gas leaks out of the center of the switch. I'm planning to order a new petcock, because they're cheap, but it won't matter if it sits the same way. Is there a gasket missing or something? On the reviews on Amazon for the petcock part, another guy had the same problem, and he said he had to cut the edge of the switch down to make it work. I'd like to avoid doing this, so there must be another solution. Any thoughts?