I just finished an ARF and when I tried to fuel it, I got pressure in the tank. It would take fuel, but if I did not pinch the line, it would spray fuel, with the vent line on and off of the muffler. I took the tank out and out of the plane it seems ok. I made sure there was nothing pinching the lines when in the plane. I even took all of the foam out from the area because I thought that might be causing it but it still did it. This makes no sense to me since this has never happened before with any of the 10 or so ARFs I have built. Any thoughts?