Need help bleeding my Yanmar 4JH3-TE

I have a relatively new to me Yanmar 4JH3-TE on which I did the first fuel filter change yesterday. Now I have a couple of problems. The engine, which ordinarily fires instantly with no throttle, now needs large throttle input to start. and when it starts also won't hold a steady RPM and stalls when pulled back to idle.

Here's what I did: I installed a new Racor primary filter and a new Yanmar secondary filter. After that, I bled the air at the top of each filter until there were no evident air bubbles.

When the engine began to behave as I describe above, I then cracked the injector nuts on each of the 4 cylinders with the engine running to bleed each cylinder. I got bubbly fuel out of each nut which does not seem to be slowing down after 10 seconds or so of this. I've gone back to each nut a couple of times but the bubbly fuel continues, which makes me wonder if there is now air in the injection pump.

I don't see any manual pump lever for bleeding the fuel injection pump or any other place between the secondary filter and the injector nuts.

If any of you have this engine, can you tell me what am I missing?

i would try to keep that yanmar going with the throttle to see if it clears the air out. yanmars are pretty good at pushing air through.

if that doesn't work check the seals on the filters you installed. it shouldn't be that complicated. i never had to crack injectors on my yanmars.

make sure to reopened fuel valve

Thanks. Will try running for a longer period. Fuel valve is definitely open.

Racors are easy to mess up the seals. Make sure you installed the filter right as it will cause exactly the problems you are experience if messed up. Google Racor to see videos on the subject.

David

It sounds like you are getting air into the fuel system somewhere. Start at the Racors and check the O rings and make sure you didn’t leave an old O ring in with the new one. Then try to start. If the problem doesn’t change start looking at the secondary filter. Make sure the O rings or gaskets are seated properly and you didn’t accidentally leave an old O ring or gasket in and now have 2 in there. It is fairly easy to do. I don’t know exactly how Yanmars seal their filters, but check bery closely. Good luck.

Weirdly, the Racor primary that I removed had a chamfered seal at the perimeter of the filter (it is the spin-on variety of filter). The replacement filter came with a much smaller diameter square edged seal that seats around the center post, but no new perimeter chamfered seal.

So I used both the old and the new. I've always used cartridge style Racors in the past, so this arrangement was new to me. Not sure if using both seals was right or not ...

Are you sure that you have the correct replacement element. It doesn’t sound right that you added a gasket. That may be the problem but I am not familiar with the spin on Racors.

DavidM said:

Racors are easy to mess up the seals. Make sure you installed the filter right as it will cause exactly the problems you are experience if messed up. Google Racor to see videos on the subject.

David

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I once accidentally crimped the o-ring of the Racor tee handle which allowed air into the system.

The bleed procedure on my 6LPA-STP Yanmar is to crack the nut on the downstream end of the flex hose coming out of the engine mounted filter while pushing the manual pump knob atop the filter housing rather than messing with the injector lines.

Creek said:

Weirdly, the Racor primary that I removed had a chamfered seal at the perimeter of the filter (it is the spin-on variety of filter). The replacement filter came with a much smaller diameter square edged seal that seats around the center post, but no new perimeter chamfered seal.

So I used both the old and the new. I've always used cartridge style Racors in the past, so this arrangement was new to me. Not sure if using both seals was right or not ...

Click to expand...

1- air in the fuel is making it run poorly. fix air leak and will run like new again.
2-Were the replacement primary filter EXACTLY the same model number? Racor has many filters that look and are numbered nearly the same but are not. Double check with the original. If that does not work, start over with a new element and gaskets.
3- The fuel priming lever is on the mechanical fuel lift pump not the injection pump.

The questions several of you have raised about the Racor primary have me thinking. I purchased a replacement filter of the same number as the existing Racor filter that was installed when I got the boat. But removing it was nearly impossible because it was on so tight and it required a level of force that badly dented the filter. Makes me wonder if it was tightened that much to stop an air leak that may have been there the last time this was changed.

Which makes me now wonder it this is the correct filter # for that Racor housing, even though I purchased the identical replacment filter #. Unfortunately, there is no Racor product brochure with my paperwork so I don't know which Racor housing it is to look up compatible Racor filters.

Can you post a couple clear pictures? Old filter vs new and the filter head.

High Wire said:

Can you post a couple clear pictures? Old filter vs new and the filter head.

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Will do that later this morning.

Also, not having any luck looking up the filter housing online to see what part number it is.

I've now taken pictures, but it seems as if I cannot post them except from a website, but not from my laptop. Is that right? (Don't have a website where they are available.)

Also, I realized I mis-spoke about the primary being a Racor. It is actually a Yanmar primary filter/water separator. The replacement element is #YAN 120650-55020. I removed an element with a slightly different # - 120650-55010. Don't know if that refers to 10 vs 20 micron or if means something different, but perhaps that is the cause of all of this.

If could upload a picture, perhaps one of you will know the part number of the filter housing and I could look up compatible filters. But I'd have to be able to upload a picture for that ...

How to post pictures
https://www.trawlerforum.com/forums/s22/how-post-pictures-50850.html

Pictures hopefully attached below.

Additional information - the notes written by the original owner many years ago say it takes a Yanmar fuel filter part # 4230-0100. Somewhere along the line a different replacement part was used. Not sure if the one that is there now is incompatible.

Many thanks to Archie for the link to picture uploading.

Maybe time to call Yanmar and ask what filter is supposed to be used.

Comodave said:

Maybe time to call Yanmar and ask what filter is supposed to be used.

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Ordinarily I'd do that, but because the primary fuel filter is separate from the engine, it is not necessarily associated with the 4JH3-TE. I think I need to know the part number for the filter assembly so I can identify the correct fuel filter.

I was hoping someone here has the same filter assembly and could either reference that number or tell me what filter is compatible.

hi, we have a pair of 4jh3-te on our boat. on ours (circa 2003) the yanmar filter is mounted on the engine and has a screw in gray plastic bottom with wires for the water detection. i believe, last change was a long time ago, the cartridge has a square edged o-ring on top and a round o-ring on the gray bottom. i also believe the 4jh3-te has the lift pump built into the injection pump.

i'd be looking at a leaky o-ring.

based on my parts notes, the on engine filter element is part # 129574-55711.

again this is a 2003 and yes yanmar is constantly changing part numbers.

Duetto said:

hi, we have a pair of 4jh3-te on our boat. on ours (circa 2003) the yanmar filter is mounted on the engine and has a screw in gray plastic bottom with wires for the water detection. i believe, last change was a long time ago, the cartridge has a square edged o-ring on top and a round o-ring on the gray bottom. i also believe the 4jh3-te has the lift pump built into the injection pump.

i'd be looking at a leaky o-ring.

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Thanks for the feedback. I think you are referring to the secondary filter if you are referencing the one located on the engine and which has the water detection wiring. I'm referring to the off-the-engine primary filter between the fuel tank and the secondary filter.

When you said you believe these engines have a lift pump on the injection pump, I cannot find one anywhere on the pump. Where is it located?

Duetto said:

based on my parts notes, the on engine filter element is part # 129574-55711.

again this is a 2003 and yes yanmar is constantly changing part numbers.

Click to expand...

Yes, that is the secondary filter, but not the one I'm having problems with.

unfortunately all my doc on 4jh3-te is on boat in fl, but from memory the injection pump has a lift pump built-in and you have no access to it.

Okay, that would explain why I couldn't discover it. Thanks for your input John.

are you sure that the filter pictured is the problem? if not try to bypass it and see what happens. the filter on your engine should suffice.

ofer said:

are you sure that the filter pictured is the problem? if not try to bypass it and see what happens. the filter on your engine should suffice.

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No, not sure that is the problem, but I don't have on hand the fuel hoses and fittings necessary to route around the primary to test that right now.

However, once again about a 1/2 hour ago I cracked the injector nuts after re-bleeding the primary and secondary filters. With the engine running at 2500 rpm, there is a steady stream of foamy fuel at each nut when loosened, which does not reduce in volume at all even after 15-20 seconds. That must mean that air is getting into the system upstream of the injectors. Because I was able to bleed the secondary filter with not a trace of air, it must be okay. So I have concluded that the air is coming from the primary - or someplace else I haven't identified yet. I did try to locate a Racor R20T which seems to be compatible with my primary filter assembly, but no vendor nearby has one on hand, so I cannot swap that out yet.

Is it possible for the primary to be sucking air into the system and for the air to flow through the secondary with no sign of it there when I bleed the secondary? Feels as if I am missing something.

People here have inserted a clear vinyl hos at various places in the fuel delivery line in the search for what is usually a tiny stream of bubbles indicating the upstream source.

rgano said:

People here have inserted a clear vinyl hos at various places in the fuel delivery line in the search for what is usually a tiny stream of bubbles indicating the upstream source.

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Great idea.

Creek said:

No, not sure that is the problem, but I don't have on hand the fuel hoses and fittings necessary to route around the primary to test that right now.

However, once again about a 1/2 hour ago I cracked the injector nuts after re-bleeding the primary and secondary filters. With the engine running at 2500 rpm, there is a steady stream of foamy fuel at each nut when loosened, which does not reduce in volume at all even after 15-20 seconds. That must mean that air is getting into the system upstream of the injectors. Because I was able to bleed the secondary filter with not a trace of air, it must be okay. So I have concluded that the air is coming from the primary - or someplace else I haven't identified yet. I did try to locate a Racor R20T which seems to be compatible with my primary filter assembly, but no vendor nearby has one on hand, so I cannot swap that out yet.

Is it possible for the primary to be sucking air into the system and for the air to flow through the secondary with no sign of it there when I bleed the secondary? Feels as if I am missing something.

Click to expand...

I suppose anything is possible but I would not think that if you are getting that much air at the injectors that the air would not show up at the secondaries. Maybe it is getting in somewhere between the secondaries and the injection pump, but on my Lehmans that area is under pressure not vacuum. But I have never worked on a Yanmar so I don’t know.

Comodave said:

I suppose anything is possible but I would not think that if you are getting that much air at the injectors that the air would not show up at the secondaries. Maybe it is getting in somewhere between the secondaries and the injection pump, but on my Lehmans that area is under pressure not vacuum. But I have never worked on a Yanmar so I don’t know.

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What you wrote is logical but it is hard to understand how a leak could occur in the plumbing after the secondary. Also, the problem occurred after I changed the primary, so logically that is the source.

It is also suspicious that the replacement primary filter package included no perimeter chamfered gasket as was on the one I removed. I suspect at an earlier time a boatyard that changed the filter for the previous owner pulled a filter off the shelf and reused the gasket from an earlier correct filter. Unfortunately, because my new filter package did not include this gasket I also then reused the old one. The gap between the filter housing and filter is miniscule, so it may not be making up tight.

If I could locate just a replacement gasket I think this would seal up, but I have no idea how to locate a gasket of the correct diameter with a chamfer. I would also purchase a Racor R20T which seems to be compatible replacement, but none are available locally and have to be shipped in.

It really has the feel of someone earlier kluging this together by using the wrong filter - which I then repeated when I reordered the filter using that number.