Yanmar 6LYA-STP

[Mobeach]

After running this new to me engine for about a year, I noticed some light black smoke from the exhaust. I'm a newbie to Diesel engines having run outboards my entire boating career. I met the mechanic at the boat to spend some time getting oriented with the engine, and to identify any issues. In examining the turbo, he noticed some play inside the housing along with a film of oil residue. He indicated that the turbo would need to be replaced at end of season. Engine has about 1250 hours on it. Boat is a 28' BHM. He also suggested that the injectors be pulled and sent out to be serviced as well. Iam having the prepare an estimate for this work (Cape Cod,Ma). Mechanic indicated cost of $3000 for turbo job (parts and labor) he wasn't sure about cost to have injectors sent out.

Wondering if anyone here could tell me what I should plan on spending on this job. Any insight is greatly appreciated as I look to learn as much as I can about my new power plant! I also plan to shop this out with another reputable Yanmar dealer off Cape.

I also joined Boatdiesel.com and posted this question there as well.

Thanks!

 

[jojobee]

Give me a call on Tuesday. I'll get you hooked up with the local sales rep. I'll pm you my number

 

[Mobeach]

Jojo.......

Thank for the quick response and help! I will definitely reach out to you. Would he be able to let me know what it will cost? Never dealt with a manufacturer rep before.

Thanks again!

 

[djmarchand]

Carefully read my response to your question over on boatdiesel. IMO you are asking the wrong question. You should be asking why did this happen and what can I do to keep it from happening again.

David

 

[Mobeach]

Great point and thanks for your response on that site. I posted some additional info there as well. Let me know if you have any additional thoughts based on the additional info I provided.

Thanks again!

Anthony

 

[captainlarry84]

A little black smoke is not unusual. Play in the turbo also comes with time. Are you getting all of your RPMs 3800 @ WOT? If so run the boat for a while I would not be in a rush to do the turbo or the injectors. 1250 hours is just so little time.
One thing about turbos. It is so very important to let the idle after a run. That turbo spins at about 20K and it takes a while to slow down. Turning the motor off quickly stops oil pressure leaving the turbo spinning with out oil. That will wipe out a turbo quickly.
I would hone in a valve adjustment & timing belt which is do about your amount of hours., If the timing belt breaks the valves meet the pistons & your motor is done. It is called a zero tolerance motor.
Lastly if you are not getting your 3800 RPMs that could also explain some black smoke.
Your motor is rated @ 3600 RPMs continuously do not be afraid to run it there.
Great boat perfect power you did well!

 

[delucat2]

A little black smoke is not unusual. Play in the turbo also comes with time. Are you getting all of your RPMs 3800 @ WOT? If so run the boat for a while I would not be in a rush to do the turbo or the injectors. 1250 hours is just so little time.
One thing about turbos. It is so very important to let the idle after a run. That turbo spins at about 20K and it takes a while to slow down. Turning the motor off quickly stops oil pressure leaving the turbo spinning with out oil. That will wipe out a turbo quickly.
I would hone in a valve adjustment & timing belt which is do about your amount of hours., If the timing belt breaks the valves meet the pistons & your motor is done. It is called a zero tolerance motor.
Lastly if you are not getting your 3800 RPMs that could also explain some black smoke.
Your motor is rated @ 3600 RPMs continuously do not be afraid to run it there.
Great boat perfect power you did well!

If it is a LYA it does not have a timing belt..that is on the LP series. Not sure about the LYA2s or 3s.

As for running it at 3600rpms...... I'll bet you a frosty one that you will get a totally different response on Boatdiesel.

Personally, until you see serious fouling of the aftercooler with oil, there is no reason to mess with the turbo.
You will get plenty of info on this and many other topics on Boatdiesel.

Don't let anyone mess with your injectors. These are not old DD injectors that need to be replaced and rebuilt. You should not worry about this till 5,000 hours if your fuel filters are up to snuff. You don't have Racors, do you?

TonyD

2002 Yanamr LHA-240 (a LY 370 less 2 cylinders) 1500 hours.

 

[Mobeach]

A little black smoke is not unusual. Play in the turbo also comes with time. Are you getting all of your RPMs 3800 @ WOT? If so run the boat for a while I would not be in a rush to do the turbo or the injectors. 1250 hours is just so little time.
One thing about turbos. It is so very important to let the idle after a run. That turbo spins at about 20K and it takes a while to slow down. Turning the motor off quickly stops oil pressure leaving the turbo spinning with out oil. That will wipe out a turbo quickly.
I would hone in a valve adjustment & timing belt which is do about your amount of hours., If the timing belt breaks the valves meet the pistons & your motor is done. It is called a zero tolerance motor.
Lastly if you are not getting your 3800 RPMs that could also explain some black smoke.
Your motor is rated @ 3600 RPMs continuously do not be afraid to run it there.
Great boat perfect power you did well!

Larry

Thanks for the response. I hd done lot of homework (including reading many if your posts) before pulling the trigger on this one. i think your right regarding the turbo, based on your post s well as other posts on the boat diesel forum, I think this is premature....outside of some light black smoke, the engine runs flawlessly. Just got concerned when the tech indicated that a failed turbo could wipe the engine out

I seem to recall getting up to 3400 RPM, but bottom has some growth. I'm going to have another marina perform the next service. And will remove the prop to be tuned at the end of the season.

Will also have them look to ensure I'm not taking in any raw water through the exhaust. Diesels are new to me, I'm trying to learn as much as I can. I appreciate the help!

 

[Mobeach]

Delucat2

Thanks for the reply.
Great info on Boatdiesel forum that will save me thousands!!

 

[captainlarry84]

Correct I read your post wrong LY 315 @ 3300 RPMs & LP 315 @ 3800 RPMs, two much different engines. I have never seen a 28 BHM with the 315 LY all of them I have seen had the 315 LP which is the perfect fit for that motor. The 315 LY was only on the market for about 3 years also a great motor. In addition the 315 LY was a tank of a motor. That same block today is up to 480 HP! There are many LY mostly the 370 HP down my pushing 3 & 4 K. With original injectors & turbos. Based on the fact that she is a 315 which could make the motor 13 years or older, I would clean out the cooling system with Rydlime. That is one service limit the boat needs. Also there is a 1000 valve adjustment only & of course no belt.
Any pictures of the motor?

 

[Mobeach]

Larry,

Sorry should have clarified that this the engine is a 2002 370 HP.
Will have cooling system serviced. I will also confirm the prior owner completed the 1000 hour service. I'm not going to touch the turbo or injectors at this point based on comments here and boatdiesel forum. I will take some pictures next time I'm there.

Thanks again

Anthony

 

[Raider Ronnie]

Reading this reminds me I'm overdue to do a Turbo Wash.....

 

[captainlarry84]

Wow...that is very big power for your rig. I assumed it at a 315 HP. A 370 is a lot of power I had that motor in the JC. When she sold with 1545 hours the injectors & turbo were all original. She was developing full RPMs which is always the key. The cooling system was cleaned with Ridylime, valves adjusted. It is a very popular motor and I have not heard of any turbo issues.
Are you wheeled correctly? what is your top WOT RPMs?

 

[Raider Ronnie]

How does that 28 go with the 370 ?
I imagine it must cruise 20kts no problem as long as conditions allow.

Larry,

Sorry should have clarified that this the engine is a 2002 370 HP.
Will have cooling system serviced. I will also confirm the prior owner completed the 1000 hour service. I'm not going to touch the turbo or injectors at this point based on comments here and boatdiesel forum. I will take some pictures next time I'm there.

Thanks again

Anthony

 

[Mobeach]

How does that 28 go with the 370 ?
I imagine it must cruise 20kts no problem as long as conditions allow.

Ron,

I typically run it at 2500 RPMs which gives me a 17 kt cruise. If I bring it up to 2800, it gets me to 20 kts depending on conditions.

Anthony

 

[Mobeach]

Wow...that is very big power for your rig. I assumed it at a 315 HP. A 370 is a lot of power I had that motor in the JC. When she sold with 1545 hours the injectors & turbo were all original. She was developing full RPMs which is always the key. The cooling system was cleaned with Ridylime, valves adjusted. It is a very popular motor and I have not heard of any turbo issues.
Are you wheeled correctly? what is your top WOT RPMs?

Larry,

WOT is 3400 RPM's. I believe the specs indicate that WOT to be between 3425-3525, so will have the wheel checked out end of season.

Anthony

 

[captainlarry84]

You are fine at 3400 RPMs. The motor is rated for 3300, but Yanmar like them wheeled at 3400 RPMs, so when fully loaded or with some bottom growth you always get the 3300 RPMs. I found the sweet spot for 370 to be 2800-2900 RPMs. 2500 RPMs the motor is really not working very hard, that could be one of the reason for the smoke. You may just need a turbo wash.

 

[Mobeach]

Wow...that is very big power for your rig. I assumed it at a 315 HP. A 370 is a lot of power I had that motor in the JC. When she sold with 1545 hours the injectors & turbo were all original. She was developing full RPMs which is always the key. The cooling system was cleaned with Ridylime, valves adjusted. It is a very popular motor and I have not heard of any turbo issues.
Are you wheeled correctly? what is your top WOT RPMs?

Larry,

Sorry for dumb question, but what's involved in doing a turbo wash? Is that something that a tech needs to perform or is it pretty straight forward?

 

[captainlarry84]

I would say yes. They run the boat under full load. Next with the turbo filter comes off they pour in the cleaner. The process sounds simple but I would not do it myself. Things like the rate of pour and amount needed should to be gauged by experienced people.

One of the fellows down my way decided to do it on his own. Took the filter off, had his buddy run the boat. 1/2 way through the pouring process with the motor at WOT it sucked a rag out of his pocket & into the turbo.
A done deal for that unit.

Have you changed your impeller yet? That is another hard job. I learned a few tricks doing that.

 

[greg]

The 6lya-stp is a 370, not a 315. The target wot is anywhere above 3400 rpms. The 20% is not an rpm number, it is a pyrometer number.

You shouldn't be cruising that engine at anything above 3000 rpm's, and 2800 would be even better.

Make sure you photo-tach your engine. The yanmar tacjh's are notorious for being wrong. Mine reads 150 rpm's high. So when I set my cruise at 3000 on the tach, the engine is only going 2850 and I get 15 knots there.

My wot is something like 3450 with light load. I'm sure it wouldn''t hit anywhere near that with a canyon load, so I need to be conservative on the rpms on heavy load runs.

I don't have a pyro or boost guage yet, but they are on the list (though I do have an engine exhaust over temp alarm). That way I could set the load to the pyro and semi-ignore the rpms.

This is the engine I have in my boat. Boatdiesel is a great site and has helped me a lot.

Btw, more than one diesel has been done in by water ingestion coming back up the exhaust. Was there any rust or corrosion on the exhaust side or was it a nice grey/black color?

Especially on smaller boats or where there isn't much engine space (like on production sporties with twin diesels) the designers don't add surge tubes or water elevators, and water can come in either via travel lift, or waves hitting from behind.