Problem with grey & black smoke occassionally coming out of Yanmar 3G30 first time out this year. Two weeks ago, I move it 15 minutes slowly to another marina and had no problem. This weekend five minutes out, had problems during full throttle, and occassionally blew plums of smoke. Engine performs and sounds OK. Turned right around and back into the slip. Yanmar manual suggets fowled fuel? What else should I also look for?
Smoking Yanmar
- Thread starter nick - rock hall
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Sounds like the exhaust elbow is plugged
Always check it first. Stock one - just remove the hose and unbolt (four) retaining bolts. Look for coke inside. Chip it out with a screwdriver, look for cracks, and replace if necessary. The Yanmar price will vary considerably depending on who you call, so check around with several places. I was quoted prices from $160 to $480. I now have one made from black iron pipe which is better (less restrictive for more power), much cheaper (under $20 for all new parts), and simpler to check out.
Always check it first. Stock one - just remove the hose and unbolt (four) retaining bolts. Look for coke inside. Chip it out with a screwdriver, look for cracks, and replace if necessary. The Yanmar price will vary considerably depending on who you call, so check around with several places. I was quoted prices from $160 to $480. I now have one made from black iron pipe which is better (less restrictive for more power), much cheaper (under $20 for all new parts), and simpler to check out.
It isn't just the prop
Nick, I had the same problem on an 81 H30. Turned out that it wasn't just barnacles on the prop, it was barnacles on the hull, prop, etc. The boat was in Florida waters and I hadn't sailed in a couple of months, hence lots of growth. It can also be weeds, etc, like you get in SC coastal waters. Anything that causes a lot of drag will cause a diesel to overload and smoke +a lot+. I've been told it doesn't hurt the engine (can anything hurt a Yanmar?), but it sure does slow you down. Hauling out and writing a check for a thousand or so will fix the problem. Hope this helps. Dave...
Nick, I had the same problem on an 81 H30. Turned out that it wasn't just barnacles on the prop, it was barnacles on the hull, prop, etc. The boat was in Florida waters and I hadn't sailed in a couple of months, hence lots of growth. It can also be weeds, etc, like you get in SC coastal waters. Anything that causes a lot of drag will cause a diesel to overload and smoke +a lot+. I've been told it doesn't hurt the engine (can anything hurt a Yanmar?), but it sure does slow you down. Hauling out and writing a check for a thousand or so will fix the problem. Hope this helps. Dave...
Whats the engine temperature?
A cold diesel engine will smoke if run at full throttle and before the combustion chamber comes up to full operating temperature. Check your temp. gage and if its reading well below the 'normal' operating range, then check to see if the themostat is sticking in the 'open' position. Since the bay water temp. around Rock Hall MD is in the low 60s, it will take longer for the engine to come up to operating temperature. Also the 3GM30 was designed when the 'cetane' number of diesel fuels was much higher than is now delivered. You might want to try a 'cetane' booster in your fuel ... will also help retard the smoking.
A cold diesel engine will smoke if run at full throttle and before the combustion chamber comes up to full operating temperature. Check your temp. gage and if its reading well below the 'normal' operating range, then check to see if the themostat is sticking in the 'open' position. Since the bay water temp. around Rock Hall MD is in the low 60s, it will take longer for the engine to come up to operating temperature. Also the 3GM30 was designed when the 'cetane' number of diesel fuels was much higher than is now delivered. You might want to try a 'cetane' booster in your fuel ... will also help retard the smoking.
Mixing Elbo
The mixing elbo needs to be cleaned every year or replaced but very easy to clean with a pointed pick unless its too far gone than replace it. If the engine is running good and bottom and prop is all clean than its the mixing elbo very easy to check just four bolts and its off. nick
The mixing elbo needs to be cleaned every year or replaced but very easy to clean with a pointed pick unless its too far gone than replace it. If the engine is running good and bottom and prop is all clean than its the mixing elbo very easy to check just four bolts and its off. nick
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