Waterant
Senior Member
I wanted to share my solution for Yanmar (and maybe other makes as well) engine smoke, which I have had since I got the boat three years ago.
My setup:
- 2002 Mainship 430
- 2x 200gal tanks
- 2x Yanmar 6LYA-STP 370 hp diesels with ~320 hours on them
- 5gal of new Rotella T3 diesel engine oil in each engine
- The starboard engine has turbo replaced with a brand-new one
- The port engine was completely rebuilt, and the new turbo was installed. ~50 hours after rebuild
- Both engines had injectors replaced with new
- Cooling system was pressure tested
Symptoms:
- Both engines smoked heavily after a cold start while idling in the marina, any RPM, heavy grey smock (I believe it had bluesh tint to it)
- No smoke in gear up to 2100 RPM
- As soon as the turbo kicks in at 2100 RPM and up, heavy grey smoke is on both engines; amount and color are the same on both engines
Cure:
- I added 64 oz bottle of Howes Diesel Treat, Conditioner, and Anti-Gel in each fuel tank: https://www.tractorsupply.com/tsc/product/howes-lubricator-diesel-treat-64-oz
- I removed 2 gallons of oil from each engine, and in each, I added 1 quart of Lucas Heavy Duty Oil Stabilizer
so my oil level is around 50% now - on another forum, I found this being mentioned a few times as a possible cure for the smoke problem. The reason was the uneven installation of the engines in the boats, and the "full" level shown on the stick was for the horizontal installation. So basically, if you have it at the full mark, you overfilled the oil pan.
The result on both engines:
so far, ~10 hours after this was done
- Very little noticeable smoke on idle after a cold start
- No visible smoke at any RPM while running
- Engines sound happy, oil pressure is normal (I have a mechanical pressure gauge installed on each engine to confirm), temperature is normal
That issue bothered me since last summer after the port engine rebuild, and it was puzzling why both engines had the same symptoms even after both turbos were replaced and one engine was completely rebuilt and new injectors installed.
I hope this helps someone.
My setup:
- 2002 Mainship 430
- 2x 200gal tanks
- 2x Yanmar 6LYA-STP 370 hp diesels with ~320 hours on them
- 5gal of new Rotella T3 diesel engine oil in each engine
- The starboard engine has turbo replaced with a brand-new one
- The port engine was completely rebuilt, and the new turbo was installed. ~50 hours after rebuild
- Both engines had injectors replaced with new
- Cooling system was pressure tested
Symptoms:
- Both engines smoked heavily after a cold start while idling in the marina, any RPM, heavy grey smock (I believe it had bluesh tint to it)
- No smoke in gear up to 2100 RPM
- As soon as the turbo kicks in at 2100 RPM and up, heavy grey smoke is on both engines; amount and color are the same on both engines
Cure:
- I added 64 oz bottle of Howes Diesel Treat, Conditioner, and Anti-Gel in each fuel tank: https://www.tractorsupply.com/tsc/product/howes-lubricator-diesel-treat-64-oz
- I removed 2 gallons of oil from each engine, and in each, I added 1 quart of Lucas Heavy Duty Oil Stabilizer
so my oil level is around 50% now - on another forum, I found this being mentioned a few times as a possible cure for the smoke problem. The reason was the uneven installation of the engines in the boats, and the "full" level shown on the stick was for the horizontal installation. So basically, if you have it at the full mark, you overfilled the oil pan.
The result on both engines:
so far, ~10 hours after this was done
- Very little noticeable smoke on idle after a cold start
- No visible smoke at any RPM while running
- Engines sound happy, oil pressure is normal (I have a mechanical pressure gauge installed on each engine to confirm), temperature is normal
That issue bothered me since last summer after the port engine rebuild, and it was puzzling why both engines had the same symptoms even after both turbos were replaced and one engine was completely rebuilt and new injectors installed.
I hope this helps someone.
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