To insure that the problem was with the tank we ran the engine off a five gallon fuel jug.
What really surprised me was how fast that fuel can drained -- it was empty in minutes because the return line was still in the original tank.
It was then I realized that with an electric fuel pump the fuel is being continuously run through the filters and back into the tank.
So, with a setup like mine, fuel polishing should not be necessary.
There is something in the tank that blocks the pickup tube.
It only happens when making a hard left turn.
I can spin in circles making a hard right with no problems.
Raising the pickup tube ˝ inch eliminates the problem.
It looks like the tank will have to replaced.
Does anyone have a better (and cheaper) idea?