Why not give the pump a test? Take the fuel line loose from the engine and extend it with a hose to a 5 gallon can.
Then turn the key to the on position and let her pump. See if you get a positive stream for 5 gallons or if your thinking is correct and you have a gasoline problem..
I still am thinking about your sparkbox.. They are only about $20 bucks and I'd be getting a new one..
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />

professional bovine relocation specialist