Re: [Amel Yacht Owners] Black Smoke From Volvo Penta Engine Exhaust

Craig Briggs

Hi Eric,
You bring up an interesting point when you say you had the same carbon build up problem in your genset exhaust elbow, caused by not running at high enough rpm's. Unless you've got a variable speed genset, it always will be running at a high rpm (3000 or 3600 depending on Hertz), so rpm may not be the only issue. Isn't it low load that's the issue? 
So when Yanmar says to run the engine way up, no doubt they're assuming it will be in gear and will present a full load from the propeller. I think the genset analogy would be to load it with not just battery charging, but also get the Admiral to run her hair dryer, make toast, wash clothes and iron your shorts. Not a bad regimen, actually.
Sound about right?
Cheers, Craig SN#68 Sangaris

---In amelyachtowners@..., <kimberlite@...> wrote :


I had his problem with my genset. It is caused by not running a diesel at about 80% of its redline. Diesels like to work hard. Our diesels are not run that hard so is the main engine.

Yanmar suggests to run the engine way up. In my case 3000 rpm for 15 minutes  a few time a day

This blows the carbon out of the turbo and the exhaust system.



The carbon is usually glass hard.

However if the elbow is not perforated due to corrosion, I would try  to break out the carbon.

You might try something like a dremel tool with a hard steel bit, or even better a carbide bit ,or a small cutoff disk. Being that they have ordered a new elbow for you,  you could go Medieval” on the elbow.


On eBay there is a fellow that makes beautiful Yanmar elbows out of stainless steel. They are much better than the factory unit. Possibly he makes elbows for your engine.

Fair Winds


Kimberlite Amel Super Maramu #376



From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Thursday, March 15, 2018 12:16 PM
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Black Smoke From Volvo Penta Engine Exhaust



I removed the elbow in Point-a-Pitre and it was almost blocked with very hard carbon deposits.  I'd guess that it was only 30% open. Even so the engine ran well. The turbo turns freely so is probably OK.  Unfortunately, they don't have the elbow here and must order it.  Will be at least a week.  The mechanic who looked at it said the elbow should be replaced every 3 years. He says that it is not possible to just clean out the carbon, but I don;t understand why not.  It's the first I'd heard about the 3 year removal requirement and saw nothing in the Operating Manual which has all of the routine maintenance identified. Just sending this to close out the question.  Thanks for all the good suggestions.  

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