Re: Auxiliary Electric Fuel Pump

Posted by HH56 On 2014/9/6 20:13:28

I think most of us have installed the electric in the fuel line nearer the tank and plumb thru the mechanical pump. Most also have the electric pump on a switch and only used for priming and vapor lock. Pulse type electrics in the 2-6 psi range are simple to install inline but rotary pumps generally won't allow a mechanical to pull thru so need extra plumbing and check valves to let the mechanical pull around the rotary. Some rotary pumps also have too great a pressure and need a regulator.

The advantage to the the tank end approach is as you mention, the push. Also, the pump is out of sight and most of the fuel line will be slightly pressurized when the pump is on. With that length of line being under the slight pressure, it is felt by many to be the best approach to helping the vapor lock issue.

The downside going thru the mechanical pump is if there is any problem in the pump then conceivably gas could be forced out onto the ground or into the crankcase. If you didn't want to go thru the mechanical pump then to get the full advantage of the electric would require a separate line and check valve with a tie in after the mechanical pump.

There have been some various combinations of electric and hand pumps in the line after the mechanical pump. AFAIK, they work OK for priming but whether it would be an advantage in helping vapor lock when increasing suction in the line when the gas in the line already wants to bubble is a question. To my mind the looks would also be a detriment and I think harder to mount in front.