Is my fuel pump trying to tell me something?

[High Current]

My boat with a Universal M25-XP is still pretty new to me - I've only been out for a couple of sails. However, prior to starting, it seems as if the fuel pump is clicking more frequently now than it did when I tested it on the hard this spring. If I'm remembering correctly, it would click a little faster than once per second; now it's more like 2-3x per second.

I know from troubleshooting prior to launch that it clicks much faster when the bleeder valve is open - and also did so when I forgot to open the inlet shutoff valve - i.e. it clicks fast when it can't generate back-pressure. The engine's been very reliable so far but I'm wondering if the pump is giving me an early warning that the fuel filter is starting to clog? Or something is leaking? Or...?

I don't want any nasty surprises when I need the engine, but I also don't want to go crazy trying to 'fix' something that's working well. Will the engine give me other warning signs if there's a fuel issue, or will it just suddenly die / not start? I'd love some opinions from more seasoned mariners.

Thanks in advance

 

[Ralph Johnstone]

We need to know the make and model of the electric fuel pump before we can tell you anything about it ?

 

[High Current]

It's a Facet...I'm afraid I don't now the model number and won't be back to the boat for a couple of weeks. The boat is a Catalina 34 (1990).

 

[Davidasailor26]

Once per second doesn’t sound too bad. Maybe your battery voltage was just less on the hard, or there was more friction from everything being cold? Ours was getting badly clogged once and would only click every several seconds. That was clogged enough to stop the engine though.

If you doubt the cleanliness of your filters it’s probably worth changing them - that’s cheap insurance and you can visually inspect them to see what’s been building up.

 

[kloudie1]

If I remember correctly, that pump has a filter screen under that bottom cap. I think the cap does a "twist unlock" and drops down so you can access the screen. Looks kinda like this one. Check its internal screen first.
Amazon.com: Facet 480532N, Facet Cylindrical 12v Fuel Pump, 1/4 NPT, 6.5-8 psi, Red Top : Automotive
A bit of overkill, imho. The small kinda square looking Facets would probably be appropriate. Ya might want to get a new pump and rig it for quick change (electrical connections and pipe/hose fittings) ..

 

[Ralph Johnstone]

OUCH Sorry but that looks a little older than any of the Facet pumps I was able to find.

The smaller Facet fuel pumps today are the Facet Cube and under normal conditions, they click about 3 times/sec. before the engine starts and 3 times/sec. as long as you wait to start the engine. No change in frequency.

I would follow the advice of @Davidasailor26 and @kloudie1 for a new pump and new filter core. The reason I suggest a new electric lift pump is that you should spec the new pump as a "NON" positive shut off pump. Older pumps may not have this spec and if not, you boat stops if the lift pump craps up.

If I electrically shut off my Facet Cube lift pump, there is no reduction in engine speed if the fuel tank is close to full.

I've never bothered playing with the pump when the fuel tank is getting towards empty. I imagine that is when the pump starts to earn its keep.

 

[Ralph Johnstone]

This will help you find the model number on the pump mounting feet.

Facet Fuel Pump Part Numbers - Pegasus Auto Racing Supplies

The most visible number on a Facet fuel pump -- 574A -- is NOT the part number. Click here to see where to find the part number on your Facet fuel pump.

www.pegasusautoracing.com

 

[Richard19068]

It's a Facet...I'm afraid I don't now the model number and won't be back to the boat for a couple of weeks. The boat is a Catalina 34 (1990).

View attachment 217279

My pump, which is almost 40 years old and looks similar to yours, runs fast when the power is first turned on and then slows down quite a bit as the pressure builds. So, I would think that if you had a clogged filter down the line yours might start faster then slow down. I don't know what a clog of the internal filter would do .

I think Kloudie1's advice is very good "Ya might want to get a new pump and rig it for quick change (electrical connections and pipe/hose fittings) .." ....I've not had a problem with mine but do have a new setup on board. I hope to get around to changing it out before I need to but the project list is long...

 

[jssailem]

Reading your observations sounded backwards. I would expect a pump to run faster initially to build up pressure then slow or even stop when it reaches it’s designed pressure. If pressure declined, like the engine started or there was a leak then I’d expect the pump to start up and try to get to the design pressure.

Looking up the data I found this:

My new Facet pump seems to run constantly, but the old pump used to slow down or stop. Is the new pump defective?​

​

No. All current Facet low-pressure pumps run constantly as long as power is supplied.​

​

Older Gold-Flo (cylindrical) pumps were known as "Interruptor" pumps because they would start off pumping very quickly, then slow down as they built pressure. They might even stop completely once they reached their design pressure. The interruptor behavior went away when Facet changed the Gold-Flo series from breaker points to the same solid-state operation as the cube-style pumps (around the late 1990s). The part numbers for solid-state Gold-Flo pumps have an E at the end to indicate "Electronic" operation. During the transition, Gold-Flo pumps with breaker points had part numbers that ended in I (for Interruptor).​

Then I remembered the fuel return system on the diesel. It is always open. The fuel circulates back to tank if you fill and pressurize the lines. So your pump runs continuously.
The facet pump’s push fuel better than they pull fuel. They are best located near the tank. You have to check the filter as there is not a way to measure vacuum if the fuel is being pushed.

 

[Stu Jackson]

Engines 101 - The BIGGEST & BEST collection of M25 Series Universal Engine Information on the Internet, plus some M35, too This includes a link to the Critical Upgrades topic which has more engine information please read it too.

Diesel Engine - c34.org


and

Main Message Board

Discussion of all matters of interest to Catalina 34 sailors

c34.org

 

[High Current]

Reading your observations sounded backwards. I would expect a pump to run faster initially to build up pressure then slow or even stop when it reaches it’s designed pressure. If pressure declined, like the engine started or there was a leak then I’d expect the pump to start up and try to get to the design pressure.

Sorry if I was confusing: that's exactly what I expected too. A change in click rate would indicate a change in flow restriction. This could be caused by several things:
- Downstream: engine running, leaking, bleeder valve is open, blockages
- Upstream: clogged filter
- Air bubbles

I did some more digging / reading / thinking. Here's the best diagram I found for how the pump works:
https://www.early911sregistry.org/forums/showthread.php?134013-Fuel-Pump-Mystery.

It looks as if the solenoid pulls the plunger down, which should open the outlet valve and allow fuel into the outlet. Then the spring pushes the plunger up, pressurizing the outlet and pulling new fuel in through the inlet valve. Apparently the solenoid is triggered by the position of the plunger. So if the spring can't push against the back-pressure, it won't fire. Back-pressure would be limited by the spring force, and more back pressure should make it move more slowly. Diesel fuel is incompressible unless there's an air bubble, so the volume per cycle should be more or less constant.

 

[High Current]

Engines 101 - The BIGGEST & BEST collection of M25 Series Universal Engine Information on the Internet, plus some M35, too This includes a link to the Critical Upgrades topic which has more engine information please read it too.

Diesel Engine - c34.org

...and I'm an idiot . Thanks Stu. I searched the C34 message boards first, I swear, but forgot to check the Wiki. You had the answer I was looking for right there all along:

Normal pulsing should be about one pulse every two seconds without the engine running.

So mine is definitely pumping faster than "Normal" and I'll definitely be proactively investigating next time I'm on the boat. I'll post back here what I discover. Thank you all for your responses!

 

[Project_Mayhem]

I've only been out for a couple of sails. However, prior to starting, it seems as if the fuel pump is clicking more frequently now than it did when I tested it on the hard this spring

Sounds like voltage was lower before starting on the hard

I know from troubleshooting prior to launch that it clicks much faster when the bleeder valve is open - and also did so when I forgot to open the inlet shutoff valve - i.e. it clicks fast when it can't generate back-pressure.

Lower load = faster pumping