I went to change tanks and the lever got about half way between the tanks and STUCK. Luckily my CFI was in the plane with me and took the controls so i could diagnose the problem and we were probably within gliding distance of the airport when it happened, so I didnt freak out too much. The problem was is that there is 1 screw that holds on the metal backing plate (the one that has left, right, off) on it. That screw worked its way out and the lever caught it and the screw was wedged between the upholstery and the lever, after figuring that out a few wiggles later and some digging and I managed to get the screw removed and the fuel selector in place, We landed anyway since I was flying under the hood and only had about 10 minutes left. The engine never quit and this whole sequence of events probably took 3-4 minutes (seemed like an hour though). So im wondering is there any sort of fuel flow going on when the lever is between tanks? I never saw a drop in fuel pressure (I hit the boost pump just in case though) . My CFI thinks that there is probably some but when its right in the middle there could be no fuel. i ask because about the 10 o'clock position is LEFT, 2 O'clock is right and pretty much everything from 2-10 o'clock is labeled OFF?