Fuel lift pump feels hot question

[mforum]

I have a Universal M-18 diesel engine in a Catalina 27. I changed the oil recently and noted that what I think is this electric fuel lift pump feels hot after running the engine for a couple hours. It doesn’t feel as hot as the radiator cap or engine thermostat to touch but is hotter than what I could continue to touch for more than a few seconds. As best as I can this looks like a Westerbeke fuel lift pump. I can’t find a manual online for it. Other fuel pumps i.e. found on Catalina direct describe operating temperatures of -40F to 180F and I don’t think it gets hotter than the engine at about 165F. I don’t suspect contaminated fuel or plugged fuel lines since I cleaned out and pressure tested the fuel tank and replaced the lines from the tank to the fuel/water separator about 8 months ago in looking for a fuel leak (which hasn’t happened since I replaced the fuel line).

Should I be concerned about the pump feeling hot?

 

[WayneH]

My $0.02 worth and I take wooden nickels. At first glance, I'm with you about being concerned about the temperature. The pump should be cooled by the fuel flowing through it. The average person can touch a 140°F surface for up to five seconds without sustaining irreversible burn damage. (ASTM C1055)

It could be this hot because the engine room temperature might be this warm. How warm is the Racor below it? That should be at fuel tank temperature.

Now if someone who KNOWS something will chime in, we will both learn something.

 

[jssailem]

It appears you have 2 fuel pumps.
One in green and one in red

The image does not show where the hoses are connected. Are these pumps in line? Could the fuel pump you are pointing at be trying to pull the fuel from the tank through the second pump?

Heat on a pump usually involves it over working to do the job. Sucking fuel harder than it is designed to do. Trying to suck fuel through a filter that is clogged.

 

[Ralph Johnstone]

No electric fuel pump is specific to one engine. Can you get a name off the pump and contact them for temperature information ?

Also, can you hear a clicking noise from the pump before the engine is started ?

 

[mforum]

The green (left one) is a heater pump I put in for a diesel heater forward of the port settee. This T’s off after the fuel tank so are not inline and has a 1 way check valve so I don’t think the fuel lift pump would be trying to pull back from the line going to the heater or pulling air in to the system.
Wayne brings up a good point about possible radiant heat from the engine since the side running parallel to the wood backing and closest to the engine seemed quite a bit hotter than the forward or back sides which just seemed just warm.
I do hear the clicking noise before the engine is starting. I’m thinking run the fuel lift pump for 15 to 30 minutes without starting the engine to see if heats up before opening up all the lines/checking filters and having to re-bleed air out of the system. Is there any harm in letting it run without starting the engine?

 

[jssailem]

Is there any harm in letting it run without starting the engine?

No. 15 min more than enough.
Fuel should circulate back to the fuel tank.
Question
Fuel tank - Pump - Filter
Or
Fuel Tank - Filter - Pump

 

[Ralph Johnstone]

I’m thinking run the fuel lift pump for 15 to 30 minutes without starting the engine to see if heats up

Bingo ! You're the man to call next time I have problems with my diesel. That's just waaaaaaaaaaay too simple.

Is there any harm in letting it run without starting the engine?

Nope. Same as running all day while motoring all day.

I'd say to make sure the heater pump is not on but that's most likely the case last time you noticed the hot lift pump.

 

[Richard19068]

I don't know what this means as far as running the pump for 15 minutes and seeing if it gets hot but with my Facet pump (on a Universal M18) when I switch on the ignition the pump starts clicking. If I don't start the engine the clicking soon slows down to almost nothing. I assume that then the system is pressurized and not pumping much or any fuel and so not working very hard.
Just an observation.

 

[jssailem]

Your assumption is correct @Richard19068 These pumps have a cutoff pressure. As an example, here is a Facit pump that specifies it’s psi range at max/min 4.0-1.5

 

[mforum]

The pump is a facet cube type pump as Jssailem points out above.

I think WayneH’s hypothesis about the “engine room” temperature and radiant engine heat may explain it.

We had frost overnight. It was 40F / 4C air temp this morning. I let the lift pump circulate for 15 minutes before starting motor. I could feel fuel line vibrating / fuel flowing just before coming in to the fuel filter on the engine which is about 3 feet away from the pump.

The pump got only very slightly warm at about 10-15 minutes after circulating and stayed like that for another 30 minutes while I ran the motor for 30 minutes. After 15 minutes of the pump running, I started the motor. It takes about 8-10 minutes for motor to warm up enough for the thermostat to open. I ran it for 15 minutes after it warmed up at 2200 RPM with all the lockers/doors open. Engine temp got to the usual 160 F but I could still keep my hand on the coolant fill cap which was only slightly warmer than the facet lift pump. The fuel line and fuel filter on the engine stayed cold the whole time.

I found a link from a different forum in 2010 after I put in facet fuel pump operating temperature in to google.

"HOT" Facet Fuel Pump? - Moyer Marine Atomic 4 Community - Home of the Afourians

www.moyermarineforum.com

Same problem, different guy.

Next, I plan to take it out for a few hours when I get a chance with all the doors/lockers closed as usual, then if it feels hot, open everying up to dissipate heat and see if it cools down.

If it’s just the ambient temp when running making it hot, is it worth heat shielding or trying to attach a heat sink?

It sounds like a facet fuel pump can tolerate up to 180F temps.

 

[jssailem]

Diesel engines do not like just running. They need a load to push against.

If you’re going to run the engine for 20 minutes, tie up the boat, securely. Start the engine, then put the transmission in gear. It will give the engine a load to push against and extend the engine life.

 

[Richard19068]

What JSailem said.

And if you are worried about the pump, they are not that expensive. Mine is well over 20 years old. I keep a backup on the boat just in case.