Yanmar 3gm plugged exhaust.

[Grub54891]

Working in a Yanmar 3gm. Did not get the serial numbers yet but it's about 20 years old. The boat came from California to northern Wis. She has been sitting about 4 years. Well the owner want's it running for next season, we pulled it in the shop, removed impeller and fired it up. Not good. Ran terrible. Closed cooling also. Changed all fuel filters, Hooked to remote tank, fresh diesel fuel, still ran poorly. Removed exhaust and checked for a restriction, all clear. Still ran poorly. Removed riser and found turbo completely plugged with carbon, not spinning. Removed the turbo, and fired it up, and it runs fine and rev's up great.
Had anyone had an issue with a yanmar and the cause of a turbo getting so plugged it can't run? We plan on doing compression and having the turbo rebuilt or replaced, I just want to know, as I've never seen this on any Yanmar in the past. Also we will be checking the injectors, timing and and thing's also.
Thanks for any info.

 

[alldodge]

What did the air filter look like, clogged up maybe?

 

[Grub54891]

The air filter is just a screen, I believe it is supposed to have a foam element on there. The screen was clear of obstructions.

 

[alldodge]

The air filter is just a screen, I believe it is supposed to have a foam element on there. The screen was clear of obstructions.

With that if the turbo locked up then it would start over fuel it self and soot up. Hope the compression checks out

 

[Grub54891]

Well that is possible the turbo is shot. That makes sense.Right now it's jammed full of carbon, and what we could clean out didn't free it up. Hunting this week so We'll be looking further into it after thanksgiving. Thank's.

 

[rbh]

Two things come to mind, first alot of idleing will carbon up a small engine like that very fast- EGT cools before it leaves turbo and starts building up.
The next thought is that the turbo bearing seals are shot allowing oil to enter the hot area of the turbo.

 

[Grub54891]

Little update. The turbo itself is toasted. Apparently the po idled the motor a lot as they would anchor out and run the motor to charge the batteries. No genset as it was a racing sailboat. I also removed the exhaust manifold ,heat exchanger and checked it all out,as it was a salt water boat.New turbo ordered!

 

[alldodge]

Will be looking forward to hearing how it does with the new turbo, hope that was the only thing that went out. The diesel should have no issues idling for long periods of time when fuel and air systems are operating correctly

 

[rbh]

Diesel engines are not designed to idle for long periods as they produce a lot of soot, that will clog up turbos and exhaust systems.

 

[alldodge]

Guess someone needs to tell all those truckers in the rest areas.

Either way iboats is a place for opinions

 

[Grub54891]

Well, we won't know till sometime next summer, Currently we have it in the shop, getting hull repairs and paint also. Plus other issues electrical. I'm guessing the lake will be frozen soon and no launches till the spring thaw.:cold: