Hmm, I really suggest taking the plane to a local club to get some help. I suspect the problem is really something simple that will be obvious to someone looking at it, but really hard to pick out over the web.

Taking the fuel tank out to refuel? That doesn't make sense. Usually, you just unplug the fuel line from the carb or remote needle valve, if the engine has a remote needle, and pump in fuel from there. You unplug the muffler vent line to keep from filling the muffler full of fuel when the tank is full. If you can't easily reach the fuel line because the remote needle is too close to the fire wall, you can put a fuel filter or bit of brass tubing in the line to serve as a place to pull the line off to fuel.

This isn't the best picture, but it's what I had. If you look carefully behind the engine, you can see a little silver thing with fuel tubing going to it. That's the fuel filter. Because I can't reach the carb on this plane, I put the filter in there so it sticks up, and I fuel by unplugging the line from the filter instead of the carb.