Electric fuel pump on PSC 31

[AlLorman]

The electric fuel pump used to bleed the engine on my newly acquired PSC 31 was dead, but a new one came with the boat. My son and I installed it yesterday but it doesn't seem to be functioning properly. I cracked the bleed screw on the on-engine fuel filter and when we turned the pump on, there was a splash of fuel emitted, but thereafter nothing. We ran the pump for what seemed like a reasonable time and no further fuel emerged. Is the pump not self-priming? If not, how does one prime it? Can anyone who has done this job offer guidance?

Many thanks.

Al
s/v Ann West, PSC31 No. 55

[noelex77]

Electric fuel pumps don’t seem good at self priming. I used the vacuum oil extraction pump on mine to get it to prime. Once they are primed they seem to run fine with a reasonable lift height.

[orientalnc2010]

Hi Al,
You must have a different set up than what I have. What engine do you have? My 3ym30 is not designed to run the electric fuel pump unless key is turned to start. There is a manual priming pump on the starb side of the engine that is used to bleed the system. My racor filter also has a manual pump for priming the filter. This is how I have been bleeding my system after filter replacement.
A previous boat I had was equipped with a westerbeke and the electric fuel pump was activated when the key was turned to on, it was kinda nice because the system was self bleeding. Not so with the yanmar.

[RainDog]

Sounds like I have the same setup as Steve: Racor, then electric fuel pump, then manual pump on the engine itself, then fuel filter. When I turn the key, the pump kicks in. I can use it to bleed the system. I cannot tell any difference between using the manual or electric pump to bleed the system (except electric makes a mess). On a recent trip my Engine stopped running. I was in big waves so thought it was a clogged filter. After changing both filters, still no love. I realized it was a bad electric fuel pump. I replaced it with a new (much bigger, hope that is OK!) one.

What is the purpose of this pump? I thought it was required, but I noticed many other installs do not have a similar pump.

[AlLorman]

My 3GM30F fuel supply is set up like this: fuel tank to an electric fuel pump, then a Racor turbine filter, then the on-engine mechanical fuel pump, then the on-engine fuel filter. The electric fuel pump seems intended solely for bleeding the engine. It is switched (the switch is right next to the pump) to a three-way switch with the engine compartment blower. Either requires that the engine key be engaged, but the switch only lets you select either the blower, the electric fuel pump, or off. When the system is properly bled and the engine is running, the electric pump is off and the mechanical pump supplies the engine with fuel (although I guess one could use the electric pump in an emergency if the mechanical pump dies).


Having spent hours bleeding prior Yanmar engines with the ridiculous little mechanical pump lever, I liked this set, at least until I found that I couldn't prime it. I'm going to try noelex77's suggestion to use an oil extractor to prime the electric pump, but I'm open to other suggestions.

Al
s/v Ann West PSC 31 No. 55

[stevemac00]

If the pickup tube is not clogged it must be the pump since you just replaced it. Mine easily self-primes. Last year I replaced the fuel tank, reconnected the empty lines and started the engine.

[badsanta]

the electric fuel pump can be used to prime up to the engine. It will NOT push fuel through the high pressure pump to the injectors. You must crank the 3gm30 to get fuel to the injectors. crack the nut at each injector to release air then tighten. I know this is not what you asked for about the electric fuel pump working, but it is a common misconception. I use the raycor 500 and racor states that fuel filter should have the electric pump between the filter and the engine. as you should pull the fuel and put the filter under a vacuum and not pressurize it by pumping the fuel pump into the filter. Your filter may be different,

[AlLorman]

I have found the fuel hose diagram from my meager owner's manual and it shows the pump in its present position: before the Racor turbine filter. I know that you sometimes need to crack the injector bleed screws, but so far I haven't been able to get fuel to the engine filter. I'm going to try today with the manual pump.

Al

[Podjo]

If it is a Walbro fuel pump, then it should be self priming. The Walbro is rated to run dry for at least one hour. You may want to check that there is no restrictions in fuel prior to the pump. I have recently read where Nigel Caulder has this same issue, and forgot to check if there was a blockage at the bottom of the fuel pick line in his tank. He checked that by blowing into the line and listening for bubbles. I supposed if you have ever blown bubbles in your milk as a kid, you get the idea. The Walbro has an input side and an output side. If it is not marked, then you should be able to do another blow test, as it only works one way,and not the other. Good luck. Let us know what fixes it?

[wiley586]

Al - On my 31 (#44) the diagram in the owner's book shows the pump before the Racor, but this is not correct. The actual flow is from the tank to the Racor, then the line doubles back to the pump. I've always heard that this is the proper arrangement. You may want to double check the layout. I mention this because the symptoms you describe would occur if you had a vacuum leak between the tank and the pump. The most likely spot would be at the Racor. Even without a leak, you could also see this with some air in the Racor. I always found it good to manually fill the Racor to the brim.