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Old 05-07-2011, 11:07 AM   #8
blucar
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Join Date: Jul 2010
Location: Ventura, CA
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Default Re: Flathead electric fuel pump

I have been running electric fuel pumps as a supplemental backup to aid in starting and/or overcome a vapor lock for over fifty years, on various makes and models of vehicles.
It is always best to locate the pump as close to the tank as possible, electric pumps push better than they pull. When purchasing an electric pump you have to make sure that the electric pump is the type that a mechanical pump can draw fuel through.
The engineer types will tell you that you need some kind of a pump kill switch, in the event that the vehicle is in an accident, however, if you are only using the electric pump to avoid a vapor lock or as a starting aid, oil pressure switches defeat the purpose of the pump because you have to crank the engine over to get oil pressure to trip the switch.
If everything in the carb is working correctly and you turn the electric pump on to prime the system on a vehicle that has been sitting for awhile, the pump will run until the fuel system is pressurized, then the electric pump will shut down. If the electric pumps keeps running the fuel system is not pressurized, a stuck float valve, etc., is usually the problem.
Some people like to plumb electric pumps so they are in a bye-pass loop around the mechanical pump. I think that the bye-pass plumbing requires a check valve to prevent the fuel from being pumped back into the tank.
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