Fuel pump failure

[peaman]

I had just left my slip headed for a couple nights at Block Island. All was normal until I pushed the throttle up to 2000 rpm, and then it was like I throttled back. I found I could run at 1800 rpm, but if I pushed to 2000, same effect. The engine didn’t stop, it just slowed way down.

After checking a few things, I came to suspect my electric fuel lift pump. No clicking when the key was turned “on”. I used a jumper wire to put 12V directly to the hot wire on the pump, and nothing.

M25XPB installed in 2020 with 272 hours. Lift pump is pictured below.

Any comments on the very short life of this pump? Apparently I should order a spare pump along with the replacement. Should I replace the pump in kind, or should I consider some kind of upgrade? Is there no means of manually purging air from this engine (it ran okay at 1800 rpm)?

 

[Christian Williams]

You've probably already changed the primary fuel filter.

Electric Fuel Pump

Does anyone know the specification for the original electric lift-pump that Ericson pared with the Universal M25XP engine? (GPH and pressure)? Our boat is a 1985 E-32. I think that the original pump was made by Facet but I've lost track of its characteristics. The pump has been replaced...

ericsonyachts.org

 

[peaman]

You've probably already changed the primary fuel filter.

Electric Fuel Pump

Does anyone know the specification for the original electric lift-pump that Ericson pared with the Universal M25XP engine? (GPH and pressure)? Our boat is a 1985 E-32. I think that the original pump was made by Facet but I've lost track of its characteristics. The pump has been replaced...

ericsonyachts.org

Once I decided it was a fuel problem, I thought maybe filter. The Racor was replaced 6 months ago, while the engine-mounted filter was last changed 18 months ago. I always add fuel from a 5 gallon jug, road tax paid (still cheaper that fuel dock), so no red dye, and so I can always see the quality of what goes in the tank. Anyways, I did replaced the engine mounted filter and that’s when I realized that I was not purging air: no tick tick tick from the engine. With that, I was completely screwed since without purging air, I could not run the engine at all, not even at 1800 rpm.

 

[Loren Beach]

It's been a long time, but I recall reading that some of the alternative "square" pumps failed often. AFAIK the other cylindrical version lift pump from Facet has been more trouble-free. Hopefully others can chime in with up to date information.

 

[Prairie Schooner]

Yep.


Do you have a bleed valve? Ours is located at the base of the injectors on our M25 and runs back to the fuel tank. I didn't know what it was or what it was supposed to look like. Someone in its previous life had twisted the knob off and I was trying to bleed by turning the nut. The engine image is with the old one.


I replaced it and that seemed to solve our fuel problems. Replacing the Facet lift pump had not solved it, but if you don't have the noise, it's worth replacing. I eventually also replaced the old Racor preemptively.

- https://westerbeke.com/Product/VALVE/300050?productname=VALVE&productid=54202A30DAF73B1CA82D9285

 

[peaman]

The XPB had a big improvement in bleed over earlier models. Previously when I replaced a filter, all I needed to do was turn the key. That would run the pump, and you could hear it running: rapidly at first and then more labored as the air was purged. I do not have that fitting where yours is.

 

[vanilladuck]

When applying a known good 12V source to an electronic lift pump, you should hear something. When I rebuilt the fuel system on Rumour, I replaced the lift pump just out of caution that it might fail soon -- it was heavily corroded/rusty. Even if it doesn't wind up being the problem, you'll have an extra for about $50

https://ericsonyachts.org/ie/ubs/fuel-system-refit-with-a-racor-500.880/ (parts list included)

 

[Dave G.]

I second Loren's recommendation of Facet Pumps. My last 2 boats both had Facet cylinder pumps and never had an issue with either.

 

[frick]

I remember a friend got a bit of water on his yanmar fuel filter. Once wet the boat would only run at an idol.

 

[peaman]

Replacement fuel pumps online were listed for $250 or so. I found a Facet pump at Napa that matches the original exactly for only $90 (image 1). The Facet instructions call for a (required) fuel filter rated for 74 microns. Local auto supplies couldn’t pick a suitable filter without an auto model number, so I decided my 20 micron Racor filter was good enough that I could eliminate the extra one. The original pump failed electrically (image2). I wonder if the vibration of the engine caused the failure. Maybe rubber mounts or remote installation would be better.

The engine manual recommends having a spare fuel pump on hand, which I will do going forward. But it is no easy job to swap pumps on the 32-3. A fair amount of boat yoga, bruises and even bloodletting was needed. Maybe a remote installation would solve multiple issues.

 

[Loren Beach]

Facet 12 Volt Cylindrical Style Electric Fuel Pumps - Pegasus Auto Racing Supplies

Racers have relied on Facet Cylindrical-Style electric fuel pumps for many years. We can usually cross-reference your Facet part number to one of our pumps.

www.pegasusautoracing.com

Interesting vendor web page for Facet pumps. The pump model with the "lower" flow would be fine for our little engines, IMHO.

 

[Pete the Cat]

The tubular Facet pumps on the 25XP have a built in filter that I am sure few of us (I think it is 30 mc)change because it follows the 20mc Racor Ericson installed . I know from bad experience that electric pumps are especially intolerant of debris--surprised someone did not anticipate this in the installation. You did assure that your ground was good on the pump, not just putting a positive to it to test. I have had the recent experience of chasing electrical problems that turned out to be related to poor grounds when the device was actually OK. FWIW.

 

[vanilladuck]

The Facet instructions call for a (required) fuel filter rated for 74 microns. Local auto supplies couldn’t pick a suitable filter without an auto model number, so I decided my 20 micron Racor filter was good enough that I could eliminate the extra one.

As long as there is a filter before the lift pump in the flow of fuel, it should be fine. Is your system plumbed like this?

The original pump failed electrically (image2). I wonder if the vibration of the engine caused the failure. Maybe rubber mounts or remote installation would be better.

Interesting theory. The Facet lift pump on Rumour (32-3) is mounted on the fiberglass on the port side of the engine bay and I haven't seen any issues since install in late 2020.

 

[peaman]

Now that this issue is resolved, I have been thinking more about how to troubleshoot any future electrical issues at the engine. I'm just getting started, but I discovered one interesting point that would have been useful to me, and which bears passing on:

When the key switch is turned on, the alarm should sound. The alarm will have 12V at one terminal, and a "ground" terminal is connected to the + side of the fuel lift pump. Because the lift pump has relatively low electrical resistance, it can act as a ground for the alarm, and so it will sound. But if the lift pump has failed with an open circuit, as mine did, it will not. I had noticed a couple days before the pump failure that the alarm sounded weak, and then it was silent. Also, I had noticed that when starting, the engine took a half-second longer to come to life. On the day of the pump failure, the alarm did not sound, but knowing that I had no issues with either oil pressure or water temperature, I was unconcerned. I had previously checked the electrical connections at the alarm, and since the engine started easily (but with the half-second hesitation), I figured I needed a new alarm. So the lesson is, if the alarm fails to sound, check that the fuel pump runs while preheating.

Is your system plumbed like this?

Yes, that's what I have. I use a 10 micron filter in my Racor (not 20 as I wrote earlier), so I can't get too worried about missing a 74 micron filter at the lift pump, although if I ever need to disconnect the hose there, I will probably install one.

 

[Kenneth K]

When the key switch is turned on, the alarm should sound. The alarm will have 12V at one terminal, and a "ground" terminal is connected to the + side of the fuel lift pump. Because the lift pump has relatively low electrical resistance, it can act as a ground for the alarm, and so it will sound.

Could be that your boat is wired differently, but that's not my understanding of how the system works.

From the factory, there usually was no alarm, just the red idiot light for low oil pressure. That light gets positive power from the engine panel, and a negative ground from an oil pressure switch on the engine block. When people add a buzzer alarm, they usually hook it up to the same circuit, so the ground is at the engine block oil pressure switch.

It would be unusual to have the oil pressure warning circuit grounded at the fuel pump, as it needs a pressure switch to deactivate the alarm once the engine is running. And, I don't see how you ever ground something to a (+) post.

 

[peaman]

First, I have an "admiral" panel for my engine which was installed in 2020. I am going by a Westerbeke wiring schematic which is titled "Wiring Diagram - All Marine Diesel Propulsion Engines". The diagram includes circuiting for the "Captain" panel which I see has "idiot lights" instead of gauges, but the wiring at the engine itself is the same. So your circuit may be different, but maybe not by much.

The low oil pressure switch is "normally open", meaning that adequate oil pressure will close the switch. Without adequate pressure, the oil light will be on "by default", and 12V will be supplied to the + side of that lamp as long as the key switch is on. In order to extinguish the oil lamp, you need to provide 12V to the "ground" side of the lamp by either of two ways: 1) by pressing the preheat button and back-feeding through a 10A circuit breaker at the preheat solenoid, or 2) by closing the low oil pressure switch.

That light gets positive power from the engine panel, and a negative ground from an oil pressure switch on the engine block.

If this were true, disconnecting the low oil pressure switch would cause the idiot light to go off. When the engine is running, there should be 12V on BOTH sides of the low oil pressure switch.

When people add a buzzer alarm, they usually hook it up to the same circuit, so the ground is at the engine block oil pressure switch.

With a buzzer connected across the low oil pressure switch, the buzzer will sound when the switch is open, when oil pressure is low. When oil pressure rises, the switch will close, zeroing the voltage across the buzzer, so it will go silent.

Thanks for your comment, as it helps me to understand how these things work.

 

[Kenneth K]

I should clarify...

The original Universal oil pressure switch has only one lead: it is the NEG lead, which grounds into the engine block. The switch is normally closed (buzzer & light come on as soon as engine panel is powered.) Once oil reaches approx 7-10 psi, the switch is activated OPEN which breaks the ground and extinguishes the light.

Other/aftermarket switches have two leads: they are POS leads. This switch is also normally closed but opens with oil pressure. But this switch supplies + DC to the buzzer/light, which is grounded at the engine panel. Though it screws into the block, this switch is electrically isolated from the block.

As to open vs closed circuits:
A
Also, you would rarely wire an electrical component "across" (in parallel with) a switch. That would render the switch (or the component) useless. The switch is, instead, wired in series with either the + or (-) lead to the component, so it can interrupt (open) or complete (close) the circuit powering that component.