Fuel related issue on rear engine

[YankeeClipper]

Yeah, I figured that the rear pump was failed.

But why does the electric pump appear to flood the engine? Or at least it acts like it does--again, I have to turn it on and off with the just the right rhythm to keep the engine going. I would think that a fuel pressure regulator would take care of any excess pressure that the electric pump provides, so that I don't have to turn it back off to keep the engine running.