Selecting an electric pump

Question:

In this column you have mentioned using an electric fuel pump on an old carbureted car in order to prime it, or to use as a backup in emergencies. You switch it on and off as needed.

Does it matter if it is a “free flowing” type or not, so as not to restrict flow when the mechanical pump takes over? Do you use a particular brand (which is free flowing, non-restrictive)? I’d like to use this on my 1971 Buick Riviera.

Answer:

I have used both the rotary type fuel pump, as well as the old plunger type and never had a problem, but a reader named Pete Harding from Nevada had some important things to say about the subject. For one thing he recommends using a pressure regulator, and again, I have not used a regulator, but I have never used an electric fuel pump on a classic except for priming and to help in the case of vapor lock. If I were to use an electric pump on a classic full-time, I would use a pressure regulator, because an electric pump pushes fuel at greater pressure than a mechanical one and could cause problems. Here’s what Pete said: “I had starting problems with several mechanical systems, and sometimes I had problems after installing an electric pump of the type you showed in your photograph. That Bendix pump — later sold under other names — has a precision ground plunger-and-tube design that proves excellent for older fuel, but I have suffered stuck plunger problems with the later fuels. A rap with a hammer would sometimes get the pump going again, but often the remedy was to disassemble and clean the pump.

“I have now replaced the old-style pumps with the Carter rotary pumps, which have so far operated without problems. I have also heard that Airtex offers a reliable pump, but I have not used one. “You can use a metal strip and stain-

less steel band clamps to mount the pump so you don’t need to drill holes in your frame. My installations include an inline filter and a pressure regulator installed below the driver’s door for easy access, but if you want your car to be original, this may not be for you.”