The Carburetor Shop LLC
204 East 15th
Street Eldon, Missouri 65026 Home | History | F.A.Q. | Orders | Contact Us | SELL TO US Carburetors | Repair Kits | Other Parts | Literature | Tools | Articles | Troubleshooting | Carburetor Identification Passenger Kits | Truck Kits | Tractor Kits | Industrial Kits | Marine Kits | Multi-carb set-ups Car Comics | Car Records | Car Trading Cards | Subscription Cards | Oakland and Pontiac Electric fuel pumps, regulators, and older vehicles There are a number of reasons car enthusiasts look
at electric fuel pumps. The most common being hard initial starting due to
modern fuel evaporating from the carburetor overnight. Whatever the reason,
there are a number of considerations when deciding to install an electric
fuel pump: (1) Is the installation legal? Electric fuel pumps
should be installed with the permanent wiring activated by something like an
oil pressure switch, such that in the event of an accident and the driver
becoming incapacitated, the electric fuel pump would automatically be turned
off. Temporary wiring to a push button can be used to activate the pump and
fill an empty carburetor. Release of the pump button will kill the pump, but
there will be sufficient fuel in the carburetor bowl to start the engine and
run until the oil pressure comes up to activate the permanent wiring. (2) Does the pressure produced by the pump fall
within the parameters required by the carburetor? This question has more than
one issue and should be considered carefully. Think of the difference in
methodology of the electric pump vis-à-vis the stock mechanical fuel pump.
The electric pump is more or less a constant pressure, constant volume pump
(assuming the GPH of the pump is greater than the maximum demand of the
engine). The stock mechanical pump is driven by the engine; therefore volume,
and to a lesser extent, pressure, is a function of the RPM of the engine.
Thus it is quite possible, if the wrong electric pump is chosen, to have a
pump that floods the engine at idle, and has insufficient volume to maintain
proper carburetor bowl lever at wide open throttle. (3) Because of (2) above, many enthusiasts opt for
an adjustable inline regulator. Many of the less expensive regulators
regulate pressure by regulating volume. Thus getting the pressure
sufficiently low to not flood the engine at idle then limits the volume
necessary to drive the vehicle at highway speeds. And just because the dial
on the regulator states some number, do NOT ASSUME that the output pressure
from the regulator is what the dial indicates. ALWAYS check the output
pressure with a calibrated fuel pressure gauge. A return fuel line from a
connection just before the carburetor back to the fuel tank is MUCH better at
reducing idle flooding than a regulator. Summary – the electric pump IF properly selected
and properly installed, may be of benefit to the enthusiast. Do it wrong, and
one had better check with their insurance agent about fire BEFORE installing
the pump! |