Exhaust soot

[EASLOOP]

When first starting my Bukh DV10 - ie from cold - an amount of black stuff blows out of the exhaust. it settles on the water rather like black soot. After about 30 to 45 seconds it goes away never to return until the next cold start on a following day.
Does anyone have an idea of what might be happening. It's not oil or diesel as that would spread out very qucikly. this stuff just floats there.
Looking forward to your replies
Rgds
John

 

[savageseadog]

It's just partially burnt fuel from poor combustion of the first few firings of the engine. Some engines use fuel enrichment as a starting aid which worsens it, don't know about the Bukh.

 

[EASLOOP]

Thanks. I am glad you said that. I had an idea it was something like that - if I load my wife's diesel car under hard acceleration it spurts out quite a bit of smoke/soot etc, even from new. My engine does not use enriched fuel - though having said that i'm not sure!?
Thanks again

 

[Impaler]

My Yanmar GM10 does exactly the same and I've been told not to worry about it, so I just have a beer.

 

[savageseadog]

[ QUOTE ]
Thanks. I am glad you said that. I had an idea it was something like that - if I load my wife's diesel car under hard acceleration it spurts out quite a bit of smoke/soot etc, even from new. My engine does not use enriched fuel - though having said that i'm not sure!?
Thanks again

[/ QUOTE ] A diesel engine is increased in power simply by increasing the amout of fuel metered by the injection pump. If you try to change speed (power) by increasing the fuel there will be a period during which the engine will accelerate up to the new speed it can do. During that period the engine won't draw enough air in to completely burn the amount of fuel you've pushed into the cyliders. As the engine reaches the new speed the burn will be more and more efficient, hence the puff of black smoke then going clean. It's basically the same situation as when you start the engine.

 

[Poignard]

I have a BUKH DV10 and it's the same. The engine doesn't smoke or use any oil and pushes the boat along at almost 6 knots with no effort. The only problem is the black stain on the transom.