I recently bought a project plane (not running) and when I put fuel in the right tank (13 gal, 2 compartment) the inside tank began to leak. After cutting the fabric and finding the leak it appears to be coming from a seal between the sump (black part) and the main tank (white). Can anyone shed some info on how these 2 pieces are sealed together and how I can fix the leak? I don't think the tank has ever been used. I smeared some blue rtv where it was leaking to show the location.see attachment.