Classic/Antique Car Repair: 6 Volt Fuel Pump, electric fuel pump, vacuum gauge

Question
I have a 49 Lincoln Cosmopolitan with a vacuum fuel pump. It won't pull enough gas to start, so I'm thinking of adding an electric pump to use when needed. Any suggestions for brands or problems I might encounter?

Answer
Ok, here is my 2 cents worth. Before I installed an electric pump I would want to know several things first. I would want to know why the fuel pump will not pick up the fuel for a start up. If it is a problem with the lines, or the pick up in the tank, the electric fuel pump will fail in short order. My experience with these Lincolns is that for normal driving the mechanical pump will serve the purpose just fine. Over the years I have used electric pumps as a booster to help prevent vapor lock if I was using the car for parades where it was stop and go and usually hot. I would connect a vacuum gauge to the inlet side of the mechanical pump and crank the engine over. There should be 11” or more of vacuum present. If it is low then the mechanical fuel pump is weak and needs attention. If it is ok, reconnect the line, then go to the fuel tank and disconnect the line. Attach the vacuum gauge to the line and crank the engine again.  If the vacuum is lower then there is a pin hole in the line somewhere that is letting air in a breaking the vacuum. All right, now having said all that I usually use a Carter in line pump. Now electric pumps are pushers and need to be located as close to the fuel tank as possible and about as low as the bottom of the tank. This will push fuel to the inlet of the mechanical pump or if you have bypass valves installed it can feed the carburetor directly for start up. You will have problems if you try to use the inline pump not turned on. It must run for fuel to flow unless you have bypass valves set up.