Fuel lift pump

I am wanting to get a few more years boating in and am working with pretty savage arthritis so some things are proving difficult, one of these is priming the fuel system on a Ford with the lift pump.
Can I install a 12volt fuel pump in the line between the tank and the lift pump purely for priming.
if so my intention would be to only utalise it for this function, turn it off once injector pump primed and run as normal.

Is this practical, will diesel flow from the tank through the 12v pump to the rack without disruption.

A lot of people do that. As to whether or not the fuel will flow through the pump during normal operation probably is a question for the specific pump. If the pump does not let fuel flow through it then a couple of valves could let it be inline during priming and offline during normal operation. Do you have Racor filters? If so they sell a pump that can be put into the filter and do the priming for you. The pump is RPK-1912 for the 12 volt version.

Yes you can. Many threads on this forum pertaining to that. Use the search button at the top of the page. Search on fuel pump, electric fuel pump, prime Lehman. Etc.

Here is one.
http://www.trawlerforum.com/forums/s32/ford-lehman-fuel-pump-45358.html

Electric fuel pumps and lift pumps have valves the allow the fuel to only travel toward the engine. If both are installed inline, either can draw fuel thru the other with or without the other running. I have twins and 2 generators. All have a electric fuel pump inline to make filter changes and bleeding easier. In any of the primary lift pumps should fail, all I have to do is switch on the electric and continue cruising. I have arthritis, too.

Lepke said:

Electric fuel pumps and lift pumps have valves the allow the fuel to only travel toward the engine. If both are installed inline, either can draw fuel thru the other with or without the other running. I have twins and 2 generators. All have a electric fuel pump inline to make filter changes and bleeding easier. In any of the primary lift pumps should fail, all I have to do is switch on the electric and continue cruising. I have arthritis, too.

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I completely eliminated the lift pump and use only a Walbro electric pump.

catalinajack said:

I completely eliminated the lift pump and use only a Walbro electric pump.

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+1
One of the best thing I ever did.........

Comodave said:

Do you have Racor filters? If so they sell a pump that can be put into the filter and do the priming for you. The pump is RPK-1912 for the 12 volt version.

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Hey that is a nice add-on. Thanks for this! Added to my list of cool things to potentially have.

It is about $300 but I like the simplicity of it. Not more fuel line connections.

catalinajack said:

I completely eliminated the lift pump and use only a Walbro electric pump.

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How does that deliver the proper amount of fuel depending on the throttle setting? Did your engine have that as an option? I've seen it done on some generators.

Anyway the OP is looking for a primer pump. A very nice accessory indeed.

Comodave said:

It is about $300 but I like the simplicity of it. Not more fuel line connections.

Click to expand...

If Arthritis is the reason, surely a friend or young relation would charge less for a once in a long while 5 minutes of helping you.

On my engines, the filter changes don't require pumping. gravity fills the primaries, turning the engines over fills the secondaries. Neither need changing very often. The fuel here is delivered clean and stays that way in my tanks. The primary bowls look bad in about 4 years. The secondaries last longer.

Mine is rigged like this with an inline electric fuel pump on a switch that flows through the lift pump on my Perkins 4.236. Works like a charm for priming filters and bleeding the system. Also, it is there as a backup for normal operations if the lift pump fails.

caltexflanc said:

How does that deliver the proper amount of fuel depending on the throttle setting? Did your engine have that as an option? I've seen it done on some generators.

Anyway the OP is looking for a primer pump. A very nice accessory indeed.

Click to expand...

An electric primer pump I understand, but how do you size the electric pump flow to satisfy the full range of engine operation. I expect the fuel return will send excess back to the tank. But how to choose the right pump?

caltexflanc said:

How does that deliver the proper amount of fuel depending on the throttle setting? Did your engine have that as an option? I've seen it done on some generators.

Anyway the OP is looking for a primer pump. A very nice accessory indeed.

Click to expand...

Mine are Lehman 120s. Pump delivers more pressure and volume than needed. Also acts as a priming pump after changing filters. Eliminated the on-engine diaphragm pump as being redundant. Plus, if the diaphragm ever failed I now don't have worry about filling my oil sump with diesel fuel. The Walbro pumps are very reliable. I don't keep a spare because I have twin engines. Replacing would be a breeze if one did fail. Not so much with the on-engine pump on a Lehman.

Soo-Valley said:

An electric primer pump I understand, but how do you size the electric pump flow to satisfy the full range of engine operation. I expect the fuel return will send excess back to the tank. But how to choose the right pump?

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My engines are Lehman 120s. The return flow is measured in ounces per hour.

Soo-Valley said:

An electric primer pump I understand, but how do you size the electric pump flow to satisfy the full range of engine operation. I expect the fuel return will send excess back to the tank. But how to choose the right pump?

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Also, I think all pumps are rated for both volume and pressure. One just needs to know what a particular engine requires to match an electric pump to that engine.

koliver said:

If Arthritis is the reason, surely a friend or young relation would charge less for a once in a long while 5 minutes of helping you.

On my engines, the filter changes don't require pumping. gravity fills the primaries, turning the engines over fills the secondaries. Neither need changing very often. The fuel here is delivered clean and stays that way in my tanks. The primary bowls look bad in about 4 years. The secondaries last longer.

Click to expand...

That works fine for scheduled filter changes, how about when you are out in the boonies?

As everyone else has said, what took you so long?
Yes. I still have the scar from the hole in my left hand from priming using that lift pump.

The only thing I will add is that I did not want the fuel to flow thru the unused electric pump. Why add to the lift pumps work.
So I plumbed the lines in parallel, This does require 3 valves. At first I just added the "T" with a valve to direct flow to the electric pump, but then the electric pump just pumped fuel around in a circle, without priming anything.
So I added two more valves on each side of the electric pump.
I also used a remote solenoid for the pump, so I can be at the secondaries and instantly turn off the pump as needed.
It's worked well for 5 years.
And it provides a backup to the lift pump.. Just in case...

The electric pumps as I understand are on demand pumps.


They supply up to their rated pressure/capacity but internally bypass if there is no demand from a carb or injection pump.


In other words another bypass not required.

My pumps were installed inline by the PO and never hooked up electrically. They sat there unused for 5 years or more before I got help here on TF identifying them and then connecting them. There were no issues with flow-thru on the idle inline pump.