Yamaha inboard diesel

[Photchkiss]

I have a Yamaha ME 432 Hydradrive (315HP) on my coastline RIB and it is suffering with huge turbo lag so much so that occasionally I can barely get 10kts out of the boat. There is a bit of black smoke but apart from that the engine runs very smoothly. I have had the turbo replaced and refurbished and the position seems to have got worse: Any ideas?

[willk]

I'm sure you've checked if the wastegate is stuck open?

[Photchkiss]

Originally Posted by willk

I'm sure you've checked if the wastegate is stuck open?

My engineer says it doesn't have a wastegate.

[beamishken]

How was the turbo refurbished? You can't get repair parts such as turbine shaft & compressor wheels so refurbishing might have consisted of a clean up, sand blast & new bearings & seals. Often the problem with marine turbos is caused by corrosion around the turbine wheel which gradualy wears the wheel down & increases the clearance between turbine & housing resulting in reduced boost pressure. A few companies will alter the housings to accept a garret centre cartridge which cures the problem.
Assuming nothing else has changed, props changed or lots of weight added (flooded below deck etc) and the hull hasnt sat in the water all winter my next step would be to check the boost pressure & ensure there are no boost leaks & the intercooler is clean as they can become badly coked up causing issues.
The fact it smokes under acceleration suggests its fueling up but either overloaded or lacking low end boost rather than a fueling problem

[SoCal Hurricane]

I have to agree that the black smoke is the indicator that it’s most likely a turbo/boost issue and probably not spooling up. We have a Parker with a Volvo coming in later this week with the same exact issue. I’m looking forward to diagnosing and fixing this one!

Good news is that it’s not white smoke! That’s a whole other expensive issue.

I’m more familiar with Cummins, yanmar and Volvo but I can’t imagine that you can’t rebuild it or find a kit that will work.

I would reach out to banks performance, Dave’s auto center in Utah (he’s also on YouTube and top tier diesel guy, and lastly diesel Dave from the diesel Bros (also on YouTube).

[beamishken]

Originally Posted by SoCal Hurricane

I have to agree that the black smoke is the indicator that it’s most likely a turbo/boost issue and probably not spooling up. We have a Parker with a Volvo coming in later this week with the same exact issue. I’m looking forward to diagnosing and fixing this one!

Good news is that it’s not white smoke! That’s a whole other expensive issue.

I’m more familiar with Cummins, yanmar and Volvo but I can’t imagine that you can’t rebuild it or find a kit that will work.

I would reach out to banks performance, Dave’s auto center in Utah (he’s also on YouTube and top tier diesel guy, and lastly diesel Dave from the diesel Bros (also on YouTube).

Same base engine as 6lp but doesnt use the same IHI turbo, afaik Yamaha will sell you a complete turbo or nothing. But there are folk here in the uk who will convert to a Garret cartridge. Last qoute I got was under £1k

[Photchkiss]

Thank you for your detailed message. The answer is I don't know as this was done by the engineer I have and he sent it away for the refurbishment process: I will find out as it sounds very much as if it could be the problem. I have had two turbos fitted and in the first instance apparently only one half (?) was fitted into the housing - this marginally improved things but then matters deteriorated. Then the whole unit was sent away for 'refurbishment' but maybe as you say that might be the issue. The boat has been out of the water all winter has no water in it and no props changed. I guess next step is to check pressures.

[Photchkiss]

Thank you!

[beamishken]

Originally Posted by Photchkiss

Thank you for your detailed message. The answer is I don't know as this was done by the engineer I have and he sent it away for the refurbishment process: I will find out as it sounds very much as if it could be the problem. I have had two turbos fitted and in the first instance apparently only one half (?) was fitted into the housing - this marginally improved things but then matters deteriorated. Then the whole unit was sent away for 'refurbishment' but maybe as you say that might be the issue. The boat has been out of the water all winter has no water in it and no props changed. I guess next step is to check pressures.

I just looked in the manual i have here for the boost pressure but it only gives the 420sti pressure which is probably totally different to the 423

If you can find a helpful Yamaha dealer they have access to all the manuals online Davie here on the forum might help & will supply you any parts you need.

The 420 manual only gives boost pressure at 3800rpm which may not identify your issue as you say it's fine at high rpm. You probably need the pressure reading at 1800rpm ish.

Removing the exhaust elbow & looking into the exhaust area might give you a clue the turbine wheel needs to be tight in the housing similar to this picture, what you often see is a buildup of corrosion which wears away the turbine wheel then flakes off removing material, further increasing the gap reducing the efficiency

[beamishken]

I recently came across this site https://en.impex-jp.com/
Based in japan they do a huge range of yamaha diesel parts & do actually list individual turbo parts which is something uk turbo rebuilders didnt seem to be able to get hold of. Possibly your turbo guy has been obtaining parts from them, doesn't help your current issue but may be handy if you do need any parts in futue, a complete replacement turbo is listed as quite a good price

[SoCal Hurricane]

OK, just finished up about an hour ago. The turbo was fine! The culprit was a valve adjustment. I would suggest pulling the valve covers off and re-adjusting both the intake and exhaust valves.

As long as you can turn a wrench, this is very doable on your own.

Think of it this way, if someone took a big puff from a cigarette and blew it right in your face, do you think you’d be able to run at full speed? My assumption is that your engine is choking on exhaust gas.

[Photchkiss]

Thank you for all your comments.

A bit of progress and more understanding. Two years ago I had a new turbo core (PS I'm not an engineer so forgive if I get terminology wrong). 3 months ago a new refurbished turbo with garret cartridge and stainless liner. When tested today we were getting 3400 revs in neutral so not fuel pump problem (I am told) but under load there was no pressure from the Turbo at all with pressure gauge after the turbo.

I am trying to get another turbo of a working engine to see if the turbo is the problem and if so I will buy another one. Any ideas where I could buy one?

[Photchkiss]

Thanks I will take a look to see if I can get replacement turbo

[beamishken]

Originally Posted by Photchkiss

Thank you for all your comments.

A bit of progress and more understanding. Two years ago I had a new turbo core (PS I'm not an engineer so forgive if I get terminology wrong). 3 months ago a new refurbished turbo with garret cartridge and stainless liner. When tested today we were getting 3400 revs in neutral so not fuel pump problem (I am told) but under load there was no pressure from the Turbo at all with pressure gauge after the turbo.

I am trying to get another turbo of a working engine to see if the turbo is the problem and if so I will buy another one. Any ideas where I could buy one?

The garret turbo conversion should have cured it its the got to fix for those turbos, unless theres something faulty with the turbo repair. The engine should make roughly 4150 high idle (wot with no load) thats roughly where the governor is set so its not making full rpm even without load. But no turbo pressure says theres something amiss turbo wise
This company have the turbo listed at under 1700 euros the site is in jpy but will calculate in euros but not £'s
Even factoring freight & duty thats cheap
https://en.impex-jp.com/

[Photchkiss]

Originally Posted by beamishken

The garret turbo conversion should have cured it its the got to fix for those turbos, unless theres something faulty with the turbo repair. The engine should make roughly 4150 high idle (wot with no load) thats roughly where the governor is set so its not making full rpm even without load. But no turbo pressure says theres something amiss turbo wise
This company have the turbo listed at under 1700 euros the site is in jpy but will calculate in euros but not £'s
Even factoring freight & duty thats cheap
https://en.impex-jp.com/

Thank you - looks like a new turbo!

[beamishken]

I'm assuming you've checked the intercooler & air filter are clear? If you remove the air intake can you spin the turbo compressor wheel with your fingers or observe it spinning when its running? The conversion you had done is a good repair but nothing is foolproof but might be a relatively easy fix, a straightforward turbo repair would only be a few hinderd & your garret cartridge conversion means service parts are readily available.

[Easedalenovice]

Originally Posted by beamishken

I'm assuming you've checked the intercooler & air filter are clear? If you remove the air intake can you spin the turbo compressor wheel with your fingers or observe it spinning when its running? The conversion you had done is a good repair but nothing is foolproof but might be a relatively easy fix, a straightforward turbo repair would only be a few hinderd & your garret cartridge conversion means service parts are readily available.

What do you mean by a few hinderd see above

[tinker]

Think its supposed to be a hundred, same fat fingers as me lol.

Great thread BTW, some cracking information on deisels inboards, wonder if I could fit one in my aerotec.......