Without knowing running pressure, and a good volume test we are all just guessing. You can fill a bottle right in the garage. See if the fuel has any bubbles and what kind of volume you get. With that information we can point you in the direction to look. Generally it's either a restriction or sucking air from somewhere before the pump. For what it's worth, an electric fuel pump has several advantages over an engine mounted mechanical pump: 1. It primes the carb before the starter does anything. 2. It allows for fuel lines to be run anywhere, especially where its cooler away from the engine block or exhaust manifolds/headers. 3. (MOST IMPORTANT) You can empty the gas tank with it....without sucking on a hose for a siphon! Some may not consider an electric pump...ummmmm....traditional. I like reliability and short cranking times better than "traditional".