Diaphragm Lift Pump Life

[Ballsnall]

Originally Posted by Jammer

Why the lift pump in particular? Where do you stop? 20 years is a long time for the main seals too.

Engine components are designed to last the design life of an engine which is commonly measured in hours but fuel burn is the most accurate measure. Ancillary components like fuel & water pumps, turbos, alternators etc can make engine life but are considered maintenance items and are changed on schedule or condition. A major factor in when they require replacement is age, so this should also be assessed, not just engine hours.

If your wealthy and can replace on schedule rather than condition, that's a nice luxury. For the OP, 2% fuel in oil is not abnormal for an old engine and I would guess it's not the fuel lift pump unless you coincidentally measured it at the exact time it just started to fail, possible but unlikely.

Buy a spare or just replace it anyway as the rubber diagram is definitely at end of life. Water pump, I wouldn't bother as they usually run many hours with a minor leak giving you plenty of warning.

[sailorboy1]

I can tell some posters never boat in places of no services

[Shanachie]

Originally Posted by Jammer

Why the lift pump in particular? Where do you stop? 20 years is a long time for the main seals too.

As previous posters have pointed out, it makes sense to regularly replace inexpensive items that can fail and cause you major problems.


Should you rebuild the diesel? No, especially because many will run 10,000 hours or more if properly maintained. But hoses, impellers, fuel pumps, thermostats, fuel filters, etc., are all inexpensive.


My list of failed items over five years on my current sailboat include fuel pump, water pump">raw water pump and impeller. In all cases, it was on me because they were on my someday list.


It's like oil changes. Yeah, you can probably go 150 or 200 hours without damage to the diesel. But why? Change it every 50 to 100 hours and know that you are not damaging the diesel.


When my raw water pump went, I was off 10,000 Islands near the Everglades in western Florida. There was a lesson. Eighty miles from civilization and minimal wind.



we made it to where we could get a new pump -- in part because of a lucky afternoon sea breeze -- but it was a good lesson in preventative maintenance.


Careful people will still have the occasional disaster, but not nearly as often as people who trust to luck.

[Wotname]

Originally Posted by sailorboy1

I can tell some posters never boat in places of no services

Which is exactly why you should be able to service every item on the boat yourself.

[Wotname]

Originally Posted by Shanachie

...........
we made it to where we could get a new pump -- in part because of a lucky afternoon sea breeze -- but it was a good lesson in preventative maintenance.


Careful people will still have the occasional disaster, but not nearly as often as people who trust to luck.

The great thing about preventive maintenance (scheduled maintenance) is that you get to choose the time and place of the work. Only fixing stuff when it breaks means the engine gets to choose the time and place. The engine never concerns itself about your convenience.

[bil56]

fuel pump: the choice for our association boat with Yanmar 1GM10 was to fit an electric fuel pump, 20€, connected to the + after ignition of the engine panel, a plate and gasket in place of the old one.
What happiness such an easy purge after changing the filter ...

[Goodxcharly]

I would change the oil and run the engine at a working rpm for several hours/days. Then have a oil test for diesel.
Hopefully it will give you a more honest result in your favor since you mentioned you are only running the engine around the marina.
I wouldn’t over react to a oil test.

[sailorboy1]

the topic isn't really about the oil, it is about life of lift pumps

[sinnerman]

Too bad they do not sell a rebuild kit. All it would require is replacing the diaphragm and nitrile flapper valves.... Save $$$

An option is to get rid of the mechanical lift pump an install an electric fuel pump. Cheaper, and makes bleeding the engine a LOT easier...Plumb it directly to the engine fuel filter.

People do not realize that fuel injector cleaning/testing (and valve clearance adjustments) are maintenance items that need to be performed periodically.

Injector issues:
- Poor spray pattern - affects engine power, acceleration, idle, starting
- Incorrect "firing" pressure setting. directly affects the engine timing and engine power
- Injector "leaking/dripping" after it fires- causes pre-ignition "knocking/railing", fuel in the oil, and causes wear of the cylinder walls by washing away the oil.

Remove the injectors and take them to an injector shop for test/repair. With the injectors removed, adjust the valve clearances, (easier to rotate the engine by hand with injectors removed).

On my engine (Westerbeke/Universal/Kubota), all three injectors were found during testing to have issues: All three were firing at the wrong pressure, two were not sealing after firing (dripping fuel) and one was just squirting the fuel sideways in a stream instead of creating a "spray" pattern....

After servicing the injectors and adjusting the valves, (the clearances were "all over the map"...) the engine was a different animal. It started easier, less smoke under load, and a lot less vibration..

cheers

[Shaneesprit]

Originally Posted by sailorboy1

I have a Yanmar 4JH3E that is 22 years old with 3600 hours on it. Last month for the first time ever I got an oil analysis on it and everything looked good except there was 2% fuel in it. Maybe nothing except that have lately only been running engine at no load while in marina, may be fuel injector but don't have any smoke, and it may the lift pump leaking.

Since the engine is pretty old with a fair number of hours I wonder if I should just replace the lift pump. An aftermarket one is only $34 and it may be worth rebuilding the OEM. Then again maybe should just replace it with an electric pump.

Who has had their lift pump fail and how many hours did the engine have?

You’re asking a question you already know the answer to. So you’re Just seeking others agreement

1) Replace the pump anyway, if it did 22 years and you’re expecting the same - you had better buy a genuine Yanmar one.
2) yeap running engines to charge batteries leaves fuel in the oil. No reason for it to smoke, you may also find higher carbon deposits in the cylinder and exhaust.

Knowing this - change fuel pump, oil and filter and take the boat out for a blast on engine power for 30 - 60 mins, but as you already knew the answers to your questions, you probably know this as well.

[Shaneesprit]

Originally Posted by bil56

fuel pump: the choice for our association boat with Yanmar 1GM10 was to fit an electric fuel pump, 20€, connected to the + after ignition of the engine panel, a plate and gasket in place of the old one.
What happiness such an easy purge after changing the filter ...

My Beta Marine had one of those 20€ fuel pumps, they are mostly Chinese copies of a FACET fuel pump that cost 3 or 4 times the price.

Now I said my boat had one fitted ( I didn’t fit it ) Anyway it failed at a pretty bad time.
It was quite strong winds (nothing me or the boat couldn’t handle) and I had full sails, coming up river / tide and under a bridge where the river bends, I had hoped to round the bend to be slightly out of the wind. While motoring into said wind, and dropping the sails ( Single handing ).
Only as I started to drop the sails, the engine stopped.
I managed to throw the anchor overboard.
Before removing the lift pump and bleeding and restarting without a pump

[DShant]

I'm not convinced you have a pump problem. I would change the oil and filter and run the engine hard for a good hour or so then check the oil for fuel again. I bet your problem will have gone away.
The new part is so cheap it doesn't hurt to change it on the other hand you could do nothing and just carry an electric pump and hoses etc. to wire in if you should need it.



People have been talking about parts to replace on marine engines. A marine engine in my view is half way between a helicopter where every part has a time limit and needs to be changed out to be absolutely certain of no failure and a tractor on which farmers typically don't do anything until there is a failure and the penalty is basically nothing, you just go to the local parts place, get the part, replace it and go on with your plowing.



On a marine engine I think it is wise to keep a list of components that need to be replaced and have them replaced at engine hour intervals. Those parts include obviously the normal consumables and filters, raw and cooling water pumps, and other engine specific parts such as intercoolers on older CAT's etc. The other thing is a regular thorough inspection of belts, hoses, seeping water or oil etc. which can give early warning of parts you need to replace. Overall modern engines are incredibly durable and as many have pointed out will run for thousands of hours without any issue. Having said that I have had multiple occasions over the years of impellers and water pump failure, so do as I say, not as I do as my father used to say!!



There's no way I would just pull major parts and replace them based on some random interval even if it was a manufacturers recommendation.

[ColIn Ferguson]

I have had two lift pumps fail, both at about 35 years and 5000 hours. Both were due to diaphragm failure, one stopped pumping and the other sucked in air. Cheap and easy replacement and I now carry an electric pump for emergency use.
Not sure how diesel would get from a pump failure into the sump oil. On an engine this old it is more likely that there is some piston ring leakage.
I have never done an engine oil analysis as i don't know what I would do with the result, other than worry a bit.
I am of the "if it ain't broke don't fix it", but carry spares for early failure parts. I have had more problems from poor preventative maintenance than regular usage and observation.

[Dalestr]

Interesting problem. I've always wondered how they isolate the fuel within the injection pump from getting to the crankcase as the plungers operate from the camshaft. That might be a source but sinnerman has some very good thoughts too, particularly since your engine has a modular injection pump instead of a cassette type. Some of what follows may not apply to your engine but many others.
Lift pumps are mostly diaphragm type and one side has fuel and the other side is vented. Old cars may have had venting to the ground but marine diesels are mostly vented to the crankcase. Any fuel that seeps across the diaphragm barrier can wander right into the oil supply. A slight crack or pinhole can give a slow leak and still maintain fuel pressure. One big reason to watch your oil level closely and carry enough oil and waste jug for an oil change.

Replacing the pump would have been easy enough but I decided to remove the functional Yanmar (Mikuni) pump on my 2GM20F, block off the crankcase port and install a Facet electric cube pump nearby (#40163 from Pegasus Auto Racing). I chose one with low pressure to emulate the original spec of only 1.4 PSI.

The tough part was plumbing the original 8mm banjo fittings together; I wanted the ability to easily swap back to the old pump as a spare. To connect these I bought an 8mm coupling nut with matching threads and polished the two ends and bolted it between these banjo fittings with the original banjo bolts. With the old pump gone, I added support for this assembly using a rubber-lined clamp (over the coupling nut) mounted to a small bracket from the block.
It does make bleeding quick and no worries about the camshaft lobe positioning. Another potential advantage is many Facet pumps have a potent "dry-lift" specification for tanks that are low down (you can also mount the pump lower). It was more work but I'm happy with the result.

[wingssail]

The diaphragm on the lift pump on my yanmar 3jh failed with a pinhole leak at 5400 hours. We were getting plenty of fuel into the oil. The mechanic inspected it and thought it was alright.

I checked it again myself and holding it up to the light I spotted the hole. It was easy to change. Now I carry a spare.

As for other things, like seals, they usually go out slowly, giving you adequate warning of impending failure. So my policy is to leave well enough alone, but carry some spares.

Main seal? I changed my own rear main seal AFTER the leak got so bad i could not ignore it. Took four days. We continued to live aboard.