Considering changing to electric fuel pumps

We have an '81 Trogan with the Chrysler 360's. We just changed to the 1409 carb and made a huge difference. Also installed a pressure gauge to monitor pressure but the lake got too rough to do that. The first run went good for 20 min or so and the engine with new carb started dropping off like it was running out of fuel but would idle ok for docking. I am wondering what specs we need for an electric fuel pump. I'm seeing 2.5-4.5 @ 30GPH pumps for the 360's. Shouldn't the pressure be up at at least 7psi? Is that GPH on the low side ? Does anyone know what I should be looking at?

I keep seeing comments that the mechanical are so much cheaper in cost. I cannot find any. 3 said they can order in at $127.00 !

he's using mechanical now ,thinking of switching, according to thread.

Factory mechanical pumps that I cannot find. We put a gauge on it but the lake got too rough to test. Trying today, but we think thats the problem. Are you going to parallel the 2 pumps and put 2 check valves? The Edelbrocks are 110 GPH, is the 30 on the electric pumps enough?

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On Sacred Waters said:

........................ Also installed a pressure gauge to monitor pressure
You may want to check the USCG regs re; this!
I'm seeing 2.5-4.5
Is this PSI ?

@ 30GPH pumps for the 360's.
that should be adequate.

Shouldn't the pressure be up at at least 7psi?
With smaller ID fuel lines and limited pump volume, the demand will lower the pressure some.

Is that GPH on the low side ?
30 GPH is hopefully the pump's capabilty, and NOT your actual usage!!


Does anyone know what I should be looking at?
You want to use MPG not GPH.

With MPG, distance traveled is part of the equation..... whereas with GPH, distance is NOT part of the equation, therefor it is rather meaningless in terms of fuel economy.

Click to expand...

Also...... if you abandon the mechanical fuel pumps, and go with electric fuel pumps, you will need to install the USCG required N/O LOPS (normally open low oil pressure switch).
This cuts off power to the fuel pump in the event of engine stalling.

You will also want to install a "start-by-pass" system that will operate the fuel pumps during low oil presssure...... such as during start-up!
This is NOT a USCG requirement..... but it becomes necessary!
This involves a relay switch that would be become triggered by the starter motor's "S" circuit .

Or.......... you can install "momentary helm switches" that will allow you to manaully operate the pumps just prior to start-up.
These must be "momentary"!!!!!!


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Once had a factory fuel pump fail on my 318 ( a few boats ago!). The inlet valve rusted shut. Not sure that an electric fuel pump would work as a back up in that situation. Also, a system that has a backup that automatically takes over without any indication would be an issue for me.

I think having a backup is a good idea. I've operated my boat in SE Alaska waters for years now and trust me when you're miles and miles from home in open water you want to have some sense of reliability and assurance that you can get back to port. I have edelbrock mechanical fuel pumps installed and I plan on plumbing an additional electric pump upstream of that just after the water separator. My boat was configured this way about ten years ago and it worked great. Actually saved my life one time in a bad November storm. I don't recommend using electric pumps while running unless you're confident that the manufacture has a fail safe product. On Boeing 737 NG's they have electric boost pumps for the motors and with all the safety controls in place they still lost an aircraft due to a failed boost pump. Unfortunately in aviation it takes a catastrophe to implement change for the better.

I don't want to steer you wrong, there's a lot of good technical advice on this site but fuel system delivery isn't rocket science. Mechanical pumps to me are the way to go. Not all are the same. Carter (no longer available) was a good mechanical pump because you could rebuild it. I replaced it with a Sierra pump that was around $40 but it only lasted a year and it was a throw away. That's what drove me to the more expensive Edelbrocks. Reliable, repairable and available. In addition to the mechanical fuel pump installing an electric pump has its advantages. A backup only to the mechanical one if it failed and priming the fuel lines after a long winter layup. Like Rick said in his post it needs to be wired to USCG specs. I carry a lot of spare parts including fuel lines, clamps, belts...... you name it. Its not very often I cant get back to port so yes think safety first and be prepared for the worst, it can happen! )

If I was going to install a backup electrical to a mechanical, I'd not plumb it in series. Some mechanical pump failure modes ( stuck shut valve or ruptured diaphragm... seen both in 50+ years of boat ownership) would not be well served. If I were going to do that, I'd install a fuel tank selector valve before and after the pump, i.e., in parallel.

Yeah Capt Bob I agree with you that anything can happen. But if you have a blocked valve or ruptured diaphragm on a non-repairable mechanical pump you can either bypass it and run your electric pump to get you home or if you go with the Edelbrock or Holley (if you prefer) you can easily replace the parts with the repair kit. $30 on Summit. Sure you can install parallel fuel systems but in my opinion why make it more complicated then it needs to be. BTW i'm not a spokesman for either Edelbrock or Holley I just think they have a solid product and they're made in the USA!!

re: "...you can either bypass it and run your electric pump..."....Hence the two selector valves (.. or 2 Ts and 4 on/offs which might be mechanically simpler) . Given how most pumps are plumbed to an engine, an at-sea bypass without selector valves would be "amusing".