Try this out and see if it doesn't help your fuel tubing problem. Connect a short piece of fuel tubing to the needle valve on the engine, 2"-3" is usually a good size. Then have the fuel line coming out of the fuel tank. Connect the two lines together with a small piece of brass tubing. When it's time to fill the plane you can separate the tubing and fill the tank, and then reconnect the tubing with the brass tube. Quick, easy, and you don't need any special tools to get to the fuel line.

Hope this helps

Ken