Soot around hull exhaust outlet

[StevieH]

Engine is a 2005 Volvo MD2030, hours unknown (was a refurbed engine PO had installed by an ex Volvo engineer 5 years ago) fitted in a Bavaria 36

Always starts first time, runs well through full rev range both under load and no load, water flow from exhaust is very good, no obvious signs of smoke of any colour but when the wind. is blowing onto the stern quarter you do get a slight 'exhaust' smell. New exhaust elbow fitted 18 months ago.

The only problem is sooty deposits all around the exhaust outlet and I cannot work out what is causing it.

All thoughts on the possible cause would be greatly appreciated.

 

[penfold]

It's a diesel engine, they produce soot even when running right; unless the amount of sooty marks has notably increased it's a case of TADTS.

 

[RAFFY]

Mine does it too. Just clean it whenever swimming from boat and keep polished once a year.

 

[Tamar]

You could always put a short extension pipe out of the exhaust outlet if you are worried so much.

 

[pyrojames]

Genrally, the soot increases as the load on the engine increases. You may get more if the prop and/or hull has fouling, or if you are trying to push to hard. This is normal.

 

[Channel Sailor]

Assuming all the obvious things on an engine are OK, then I suggest it may reduce the issue if you are thorough with air filter maintenance. Saving money by not replacing paper elements or not carefully and regularly cleaning/washing a reusable one I think is a false economy. Just think of that vast amount of air that all has to be sucked through that little element for at least a 100 hours.

Another one to watch out for is not enough fresh air getting into the engine compartment. I owned a boat once with very poor air intake arrangements. My current little yacht engine has two large hoses going directly to transom mounted external air intakes.

Fouling on the hull and propellor increases the smoke on my yacht.

As other have said, some deposits are normal. If it starts easily on the button then that is one good sign that nothing serious is wrong,

 

[Tranona]

The engine in a Bav 36 operates in a very clean environment and the 2030 air "filter" is just a piece of foam rubber. I ran one for several thousand hours and the filter never got clogged and was only changed because it started to fall apart. While lack of air can cause incomplete fuel burn, highly unlikely in this instance.

 

[tillergirl]

When were the injectors serviced? I had that. No trouble at all with the engine but soot on the transom. Injector service was due so took them to Colchester Fuel Injection. They said they were 'hosing'. Inspection free, service £40 an injector, ready next day. Sooting was sigificantly reduced.

 

[Refueler]

My transom gets this when I run at high revs, even with a short extension .... and unfortunately I stained a few fenders that were hanging from pushpit !!

It cleans off transom with good domestic cleaner or toilet cleaner. But the Fenders resist all efforts !

 

[TernVI]

When were the injectors serviced? I had that. No trouble at all with the engine but soot on the transom. Injector service was due so took them to Colchester Fuel Injection. They said they were 'hosing'. Inspection free, service £40 an injector, ready next day. Sooting was sigificantly reduced.

Similar here.
Another thing that can help is an extra muffler in the exhaust, which can make more of the soot come out as dirty water instead of airborne soot.
Changing the engine oil can help too.

 

[StevieH]

Thanks for all the helpful replies. Seems my concerns are unfounded so will settle for cleaning off the soot and just keep an eye on the engine.