Turbo problem on yanmar 4jh2-TE?

[Sulaire]

I have the above engine on my boat with 2000 hours on it. After cleaning out the exhaust elbow this winter , ( it was quite badly carboned up) I expected less smoke and indeed that seemed to be the case at revs upto around 2200. After that the turbo really kicks in and you can hear the whistling.

On my first trip of the season I tried a few hours at as high revs as I could bear (2900 to 3000) there was a smell of burnt oil or diesel and what looked to be black smoke, but could be blue. The cooling water was coming out with a definite dark stain , almost black in colour and I have the usual black moustash on my transom!! At lower revs the water is clear with only a little smoke.

Question is ; has anyone had a problem with oil seals on these turbos, as I would like it to be that rather than rings /glazing of cylinders.

The engine really does run smooth and starts first time everytime with no glow required and has never given me any problems other than a black moustash that I do not want on my transom. It does use a little oil.

I could paint the transom black and forget about it I suppose!

New injectors, fuel injection removed and checked, compression fine etc etc!

Turbo rebuild experience anyone?

C.

[YankeePSC34]

How much is 'a little oil'? I would first look after the fuel injection.

[Sulaire]

Hi


Maybe 1 liter every 100 hours?

I did take off the fuel injector and have it bench tested, / serviced it was in good order and everything was firing as it should.

Do you think the blackish water is unburnt fuel?

C.

[YankeePSC34]

Yes, that's a little oil. The black smoke is definitely caused by the combustion. Since it seems to be OK w/o the turbo fan, I would check the turbo fan first to make sure the engine gets the combustion air. Also I would check the valves but that is more unlikely because you would notice a significant valve blow also at lower rpm.

[Sulaire]

Hhhmmmm... Interesting as i forgot to mention i do have a good strong blow coming from the rocker cover breather tube, and if i shine a torch at it, i can see a blue tint to the air coming out?

[YankeePSC34]

That may indicate worn valve stems. Here you can download a manual.
http://WWW.yanmarmarine.co.UK/PDFs/s...al/EPB5545.PDF
You mentioned that there was significant built up in the mixing elbow. Did you check the turbine wheel for built up?

[Sulaire]

Thanks for that, very helpful.


When i took of the elbow, and looked at the turbo blades they were black with carbon, i did not want to touch them. So left it and did a turbowash proceedure with yanmars own wash 3 or 4 times.

I do not suppose that will have shifted too much carbon, so it is looking like I will need to get a few parts for the turbo and attempt a service.

I am a relative novice, with engine tinkering beyond general servicing, so may pass on the valve stems, infact The turbo service sounds daunting too!!

As I say she runs very well, so i am loath to start fiddling about!

C

[djmarchand]

Black smoke at moderate rpms is an indication of too much load- fouled bottom or prop or too much prop or not enough air. I would sudpect too much load. If your boat has gotten heavier over the years with equipment, etc, then the prop may be over pitched. Does it reach rated rpm at wot in gear. If not consider taking a few inches of pitch out of the prop to reduce load.

David

[DeepFrz]

I would suggest that you not try to service your turbo yourself, other than cleaning. They are common turbos and you should be able to find a shop to service them nearby.

[bstreep]

As DeepFrz says, they are common turbos.

I have essentially the same engine, and I've had my turbo off twice in the last 2 years. The job.. sucks. It takes a couple of hours, and tiny hands would help. Those freakin' Yanmar engineers like the package to be pretty, not easy to work on. The tolerance is just absurd...

Anyway, take the turbo off and have it cleaned. Do NOT hit it with high pressure air - it has to be lubricated when spinning. They spin at 70-80,000 rpms - so if they don't spin very freely, they don't work right. The turbo wash is supposed to be used - get this - WEEKLY. Yeah, I laughed too.

A rebuild is somewhat reasonable, a replacement is stupid expensive. They are $250 turbos, and Yanmar charges $1600-2000.

[Paul L]

What is in the turbo wash? Can you make it up yourself?

[bstreep]

Originally Posted by Paul L

What is in the turbo wash? Can you make it up yourself?

I've been tempted, but think that a high dollar engine just isn't worth the risk. You can sometimes buy it on fleabay where someone has bought a big jug, and then broken it up. It SMELLS just like the cleaner "Fantastic". But, I wouldn't do that.

IF you take the turbo off, EZ Off Oven Cleaner (the nasty caustic kind, not the "green" kind) is often touted online as cleaners for these turbos in automobile engines.

[YankeePSC34]

The turbo is manufactured by IHI (ishi kawashima heavy industries) Japan.

[MARINE ENGINNER]

there is a special circlip in the exhaust turbine side that is also seal.every 4000hrs this needs replacement because it worns and burns oil through your turbo