RE: fuel pickup nightmare - clunk or solid pipe?
I have used many Sullivan 2 Oz. tanks with no problems. Could it be that you have a small hole in your fuel pick up? I have seen this happen before. If you have a small hole in the fuel pick up line, and the fuel level is high therfore covering the hole, then the engine runs fine. Once the fuel level drops exposing the hole to air, then the motor will lean out and quit. Just a thought.
Hec