Adding electric fuel pump

Steve Dion · May 9, 2012

Newage:

Remember that the electric fuel pump will need battery (electric) power to operate. Your diesel currently will run without any additional electrical power once it is started. If you add an electric fuel pump it is just another point of potential failure in the system. Those old manual pumps seem to work for 20-40 years with very few failures.

A lot of sailors add a hose with a bulb to pump fuel from the tank to the engine when they change filters etc. Personally I don't like any of this stuff, but many owners swear by them.

Benny17441 · May 10, 2012

It is possible to connect them together and no you do not have to run the electric all the time but some have reported that the electric pump damaged the diaphragm on their mechanical pump. I suspect the diaphragm may have already been weakened and when subjected to higher pressure it could have triggered a premature fault. In small aircraft electrical pumps are used for priming and redundancy but in a boat such installation and the maintenance that goes with it is not that critical so why bring potential trouble into the mix. I would not consider attaching anything to the fuel system unless it served to correct a nagging problem.

Snotter · May 10, 2012

I've added an electric fuel pump (suitable for diesel that I bought at a local autoparts store) to my perkins 4-154 almost 4 years ago. I only turn it on (via alagator clips) when I need to bleed the air out of my fuel system. I've seen other sailors do the same thing. My genset and main engine (all fed through the same line) run just fine with the fuel pump inline and not on. It makes the job of bleeding trivial for both the perkins and the genset.

Stu Jackson · May 10, 2012

Electric fuel pump wiring & bleeding your diesel

Good advice here. They call 'em "lift" pumps for a good reason, 'cuz some boats have the fuel tanks lower than the engine. For instance, our C34 has the fuel tank higher than the engine, but still has a lift pump for our M25 series and M-35 series engines. The fuel is reported to flow adequately without the lift pump until the tank is half full or lower, due to the routing of the fuel supply hose and the pressure drop through the line and the fittings (engineer-speak) between the tank and the engine's injector pump. Other boats from the same builder have low fuel tanks.

Bleeding without a pump has got to be a chore. I tried it once using the finger pump on the Racor and my fingers STILL hurt and that was 13 years ago!!!

Instead of alligator clips, one could install a simple hard wired setup and install a simple toggle switch.

I've done just the reverse: the fuel pump runs all the time the key switch is on, and when I have to bleed the secondary filter I have to remove the screw to bleed the air out of the sec filter; rather than spilling fuel all over during the time it would take me to go to the electrical panel and turn the main DC switch off, I put in a toggle switch in the engine compartment that I easily reach and turn the pump off when fuel starts to come out of the screw hole.

The newer Catalina and other brand engines have a dual start wiring arrangement where the pump comes on when the glow plugs are energized and then stops until the engine starts AND only resumes when the oil pressure is made. I find this kinda dumb for bleeding, but the engines are supposed to be "self-bleeding." "Self-bleeding" works for the primary filter, but doesn't always work on that secondary filter, which is why it makes me think the concept is dumb. There's another downside to this silly design:

...requiring holding the glow plugs via the keyswitch spring position ON while hitting the start button MEANS that there is a continuous draw on the battery bank from BOTH the glow plugs AND the starter motor. Our C34-group experience is that this INHERENTLY leads to tough & rough starting. The Mark I “trick” has always been to RELEASE the glow plug (button in our Mark I case) BEFORE the start button, so that both heavy amperage draws are NOT on at the same time.

and

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Another interesting sidebar to this whole "when does the fuel pump run?" issue just occurred to me after stumbling over this thread: http://c34.org/bbs/index.php?topic=64.0 or any other of the many fuel bleeding posts.

IF the fuel pump ONLY works when the glow plugs are held on with the spring switch OR when the engine is running, bleeding the fuel system is a real PITA. To successfully bleed the system, as discussed here and finally summarized by Ken Heyman (http://c34.org/bbs/index.php?topic=2884.0), it's MUCH easier to run the fuel pump without the engine on, and why would you want to have to energize the glow plugs when you bleed the engine?

Another one of those UNFORESEEN CIRCUMSTANCES and unintended consequences as a result of a "design improvement" that makes things worse, not better.
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and: http://c34.org/bbs/index.php/topic,3347.msg21275.html#msg21275

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Of course, I'm not opinionated about this at all!

In that case, I recommended to our skippers that they re-wire the stupidity out of their systems and just run the pumps all the time.

Here's a perfect example: http://c34.org/bbs/index.php/topic,5078.30.html

Good luck. You'll love that pump when ya need it!

Benny17441 · May 10, 2012

I bleed my fuel lines with the mechanical lift pump by cranking the engine with the compression levers open. A 2nd push button switch near the engine comparment helps.

Cayennita · May 11, 2012

I used an electrical fuel pump on both my Perkins 4-236 and Yanmar 3 GM. Both for 10 and 4 years respectively. They run all the time and no problems. On my latest J-36 with a Yanmar I use the bulb and works great.

sailaway78 · May 11, 2012

A little different setup

I have an electric pump on my Yanmar 3GM, but have it a little differently rigged than others. I installed some T's and ball shutoffs, to isolate the pump. I put it at the tank. With a switch. The only disadvante is having to open the ball valve.
There are several advantages. Bleeding is the first. Much simpler even than opening the compression release, and cranking the engine over. A whole bunch easier than reaching into the engine compartment, and manually bleeding. I can pump the tank out if needed, Can use it as a fuel polishing device with some success. It will push fuel through a partially clogged filter, that a lift pump will not suck through, particularly when it is rough enough or in tight enough quarters you don't want to have to change a filter at that particular time. I didn't have an electric pump for many years, but now will never be without one.

capejt · May 22, 2012

something to be considered

I had installed a "squeeze bulb" pump for changing filters and bleeding. Shortly thereafter had to have a survey done. The surveyor told me that the bulb was a safety violation and so I removed it. I'm now considering the electric alternative.

Snotter · May 22, 2012

Another nice feature of installing an electric fuel pump for bleeding: while cruising last week away from my home port, the diaphram in my mechanic fuel pump developed a tear. I thought I was going to have to get a tow home from TowBoatUS. However, I realized that I had an electric fuel pump already plumbed into the fuel line that I use to bleed air. It took 20 minutes to hack-saw through a metal fuel line and hose-clamp the line out of the pump (actually out of my primary pump which is fed by the electric pump) to the metal line, by-passing the mechanical pump. I was able to continue my trip with no issues other than the altenator staying in bulk mode for hours at a time. I suspect I need to change the charging option on my smart regulator. I am going to hold off on rebuilding the mechanical pump until the fall.