Yanmar dying

[rslifkin]

Originally Posted by Dockhead

This terminology is confusing. You might want to call the native Yanmar fine filter on the engine the "primary" one, as in, the principle or main filter. That seems right to me and that's kind of how I would like to call it.

But you, and I believe most people, call the Racor the "primary", because the fuel goes there first. And the fine filter on the engine is the "secondary".

I force myself to use it like that so people understand what I mean. We should unite around one or the other terminology.

I've always thought of it as primary and secondary based on the order the fuel flows through them. As in primary and secondary line of defense.

[Johan Leopard51]

If your fuel tank(s) have hatch you can open for inspection, have a look inside. Where we operate the diesel is called jungle juice but you can also develop problem with ‘clean’ diesel source. If vessel stood for a while with tanks not full, condensation happens inside tanks because of tropical temp and then after a while the tanks look like an aquarium. In May the starboard motor and the gennie were completely blocked so had a bit of “fun” taking the cat astern into a mooring in marina with one motor in wind…

On some vessels the tanks are ‘short’ enough that you can manually reach in and clean it, but on Leopard the tanks are quite long so very hard to clean out.

When I’m there next I am installing a polishing system : a fuel pump and Racor that automatically runs few hours a day taking fuel from tanks and putting it back in tanks. Over time I should catch the last of the old crap in the Racor.

We presently can only pump fuel from starboard to port (which supplies the gennie) and that has had issues, but with the right valves and cross connect I should also be able to pump from any tank to the other tank by way of the polishing system.

[Nic Homan]

We had similar last year after sea water got into tank….dont ask!!!!
It could be a number of different issues but if sounds like a fuel side issue.
Air could be getting into the fuel line. Especially the parts you have played with. So go through every joint to check no air is getting in. Check hoses for small splits which can allow air in.
It could be crud or water in the tank that partially blocked a line or a filter. So go through the whole system checking this aspect. It could be your injectors need replacing especially if they hav’nt been changed in 2000 hours

[Scubaseas]

What others have said but add check the elbow if any on the suction/pick up tube at the tank. As mentioned also try it with the fuel fill cap loose and if the problem goes away remove the vent hose and look for one of our forest friends living inside the tube. I had something build a nest a good 8" inside the 5/8" tube on my holding tank vent hose.

Look into Liqui Molly "Diesel Purge".

[SofaKingFishy]

You’ve got water in your fuel.

[LagoonJim]

Carone, I'll bet you have a manual priming pump(integrated yanmar component) at the engine mounted fuel filter, like my 4jh4-te(s). It will have a bell shaped metal top, you press down on the bell to pump.

If you do, take the boat out and run up rpms as you have described, wait for it to start exhibiting rpm drop and coughing, then quick check if the priming pump "bell" is sucked down. If so, drop the rpms to idle and check again, it should slowly pop back up to the "closed" position.

If you've got a manual priming pump, I bet you will see the above. If so, as other posts have stated, there is a restriction somewhere in the fuel circuit. filter, pickup, etc.

The restriction in the line creates enough suction to pull down the manual priming bulb and begin sucking in air. You have to drop rpms to idle, reducing suction, and give the pump time to return to the closed position before you get normal operation.

A flaw in design perhaps, but then again it's sort of a canary in the cage.

If that is what you observe, report back so I know I'm not crazy. :P

[jamhass]

Had a similar issue on a different engine. Turned out the emergency fuel shutoff valve had been inadvertently nearly (but not fully) shut. Once identified and reset, all was good.

[nonav]

Originally Posted by Dockhead

This terminology is confusing. You might want to call the native Yanmar fine filter on the engine the "primary" one, as in, the principle or main filter. That seems right to me and that's kind of how I would like to call it.

But you, and I believe most people, call the Racor the "primary", because the fuel goes there first. And the fine filter on the engine is the "secondary".

I force myself to use it like that so people understand what I mean. We should unite around one or the other terminology.

No need to unite…

The Racor or first filter in line is the primary, the second, or secondary is the secondary, hence the terminology.

20micron for Racor, and 2micron for the spin on at the engine.

[argonauta1]

Yup change both primary and secondary filters and henceforth never put fuel in the tank without passing it through a Bahja filter first./

[sailingharry]

Originally Posted by nonav

No need to unite…

The Racor or first filter in line is the primary, the second, or secondary is the secondary, hence the terminology.

20micron for Racor, and 2micron for the spin on at the engine.

Sorry, no uniting.


Yanmar provides the engine with a single 2u filter. They think that's all it takes. The manufacturer's instructions don't have a Racor at all.


I used the Yanmar filter mount as part of my secondary alternator mount. I had to figure out what to do with the filter. Then I realized that if I use a 2u filter in my Racor, I'm miles ahead of the Yanmar recommendation of a spin-on 2u filter. I tossed it. (I have twin filters in parallel, I can switch from one to the other in seconds -- counting opening the engine access -- and I have and monitor the vacuum gauge). My 2u filter is good for someplace between 300 and 500 hours between changes, which may be less than a 10u filter, but who cares.


So I vote for uniting behind "the Racor."


But more to this thread
- My 4JH2E does not have a manual prime pump.
- My 4JH2E lift pump is, I'm pretty sure, well below the injector pump and driven by the cam shaft.
- My 4JH2E doesn't need a priming pump. It easily self primes, and has on several occasions.

[Tillikum]

Originally Posted by Dockhead

Those Yannies don't have a separate lift pump. It's built into the injection pump.

This is a typical boat diesel problem that in 99.9% of cases is caused by fuel blockage or air leak somewhere.

I have the similar 4JH3 HTE engine and in 4000 hours of use in my ownership have experienced the same thing a couple of times.

The Yanmar secondary fuel filter is extremely susceptible to clogging up, even when it's behind a 2 micron Racor (I know that doesn't make sense).

I stopped having these issues when I started religiously changing the expensive secondary filter even when I'm getting years between the 2 micron Racors, which I don't replace until they start to pull a little vacuum.

A tiny air leak will also do this -- I experienced that when installing Maretron fuel flow sensors.

Q to the OP -- what kind of primary filter do you have? Do you have a vacuum gauge? Have you had any fuel tank issues?

https://www.youtube.com/watch?v=i04BkZJ_BW4

Filtration to as small as ~1/10 micron is claimed. Most paper filters pass particulates below about ~15 microns. ~80%+ of engine wear is caused by particulates smaller than ~10 microns.



A much larger marine unit being cleaned:

https://www.youtube.com/watch?v=Be4jtePNyj8

Notice the large amount of solids removed.


Another:

https://www.youtube.com/watch?v=gn6hnWjnlhI

An even larger amount of solids due to longer cleaning interval (neglect).


As much info as anyone could want: https://bobistheoilguy.com/forums/

[LeighWebber]

I had a 4JH2TE with identical symptoms. The problem, as many have stated, was funk in the fuel tank. Fuel "polishing" is useless if there is algae scum in the tank. You have to open up the tank and scrub it out by hand. Impossible if your tank has internal baffles, unless you cut clean-out holes -- a horrible job.

My solution was to get a metal ship to fabricate an aluminum day tank. My boat had huge cockpit lockers with ample space for a 5 gallon day tank. A smaller day tank would also work, of course.

I rearranged the fuel lines as follows. Main tank to a 30 micron Racor > electric fuel pump > day tank > 10 micron Racor > engine 2 micron filter > return lines from injectors > day tank > overflow back to main fuel tank. I put a tank gauge on the day tank, and when it got low I switched on the electric fuel pump to refill the day tank. No problem leaving it on top long -- it just overflows back to the main tank.

Now here's the magic. Any think in the (ancient) main tank will be blocked by the first 30 micron Racor, which means the fuel in the day tank is guaranteed to be at least minimally clean. The second Racor is just belt and suspenders, of course. If the 30 gets plugged, you will know because the day tank will fill very slowly. But the remaining fuel in the day tank is clean, so the engine will not be affected. This gives you time to change out the 30 without even stopping the engine.

This completely solved my fuel problems at a very low cost. The tank cost me a few hundred dollars, plus the other Racor.

Bonus -- the day tank also fed my Webasto heater, which doesn't like big vertical pulls from a low-down tank. My day tank was the same height as the Webasto.

[LeighWebber]

Sorry for autocorrect glitches -- composed on my phone.

[Tillikum]

https://finance.yahoo.com/quote/PH/

[Shanachie]

If there is bacteria/algae in the fuel tank, don't forget the Biobar or a similar product.


Once, after emptying a five-gallon diesel container into my tank, I got distracted and forgot to replace the cap. Of course, it rained heavily before I realized my mistake.


There was a bloom in my tank. I used a shock-level dose of Biobar JF, let it sit overnight, and then ran the diesel. The Racor filled with what looked like fine black dust, but the engine kept running fine.


I used a Baja filter, four five-gallon diesel containers and an inexpensive electric fuel pump to drain tank and filter the fuel. Then I drained the Racor and changed the filter.


A little more of the black dust appeared in the Racor, but vanished over time. The pressure gauge on top of the Racor had normal readings. No problems in the two years since.