Best continuous-use electric fuel pump??

[FRITZ47]

Originally Posted by sidevalve8ba

Does anyone use a a relay in their fuel pump electrical circuit? That thought just crossed my mind.

I have never used a relay for any of my cars with electric fuel pumps, but always use an under-dash push-pull switch to manually turn on the electric fuel pump for priming, as most of my cars also have conventional fuel pumps. I do NOT use a toggle switch for this purpose, as it is hard to remember which way the switch is activated. With a push-pull switch, pull is always on and push is always off. In addition to this switch, the circuit must also be wired through the ignition switch so that it cannot run when ignition is shut off (safety factor). Some users connect the circuit through an oil pressure switch of some sort for additional safety, but I have never done this.

Some users pipe in a by-pass arrangement with check valve when using an electric fuel pump and others use pressure regulators. I prefer to find a pump that does not require a pressure regulator (low psi type) and that can be used in conjunction with the regular mechanical fuel pump, and I test each one to see if I can blow through it before installing it so that I do not need a by-pass and check valve arrangement (lots of plumbing to do so). This is not a scientific test, but gives some indication of what to expect when the electric pump that is used for priming is off and the mechanical pump doing the job.

Also important is that an electric fuel pump be of a low pressure type, as if too high, it could blow the seals of the original fuel pump (if used) and could also cause other problems within the carburetor. Selecting an electric fuel pump is not an easy decision, as there are so many brands, different pressures, different voltages (6 & 12 volt/other), and the necessity of the pump being made of Ethanol resistant components. For priming purposes only, you need very little pressure - maybe only 2 psi or so. Again, remember to use Fuel Injection Hose 30R9 on any/all fuel line hoses for reasons explained in my previous post. The older style fuel line rubber hose is no longer suitable for fuels containing Ethanol.

Fritz