Dennis,
Your temporary tank setup certainly would preclude any 'debris in the system' issues, that's for sure. My only thought would be, without the pressure supplied by a fuel pump, any slight hanging or resistance of the float or needle and seat would cause the carburetor to run dry..or maybe 'shy' of fuel.
An electrical failure usually makes the engine shut off abruptly, just like you turned off the key. Fuel issues usually cause it to fizzle slowly as it gradually dies from starvation.
I would tend to agree with you on the line from temporary tank to suction side of the fuel pump. Could you convince him to try it. None of these attempts will harm the engine and shouldn't worry the gentleman that built it.
Stuart
