Well, i just looked at the center line, i would gues that the fuel tank is about 1/4 to 1/2 of an inch higher. I never thought of a pump but that seems like it would add alot of weight? Mabey not though. What if i tried to tune the engine while the plane was inverted on a stand, would this help.
Now that it think of it, last time i tried tunning the engine, it would always quit at idle, even if the air bleed whole was wide open.