Yet another white smoke question!

[David W]

This is not my video but it represents what I see from my 1978 2QM15:
http://www.youtube.com/watch?v=iCaEQb888gY&feature=youtube_gdata_player

The exhaust elbow and manifold were recently replaced. I'm considering a valve adjustment and either new or rebuilt injectors to see if the amount of smoke can't be reduced a bit.

Thoughts?
Many thanks,
David

 

[kloudie1]

Dunno, David; Looks more like steam/ water vapor from hot exhaust and cooling water meeting cooler outside air and water.. ..seems to have plenty water flow .. doesn't look like un-burned fuel.. if the outside air temp is around 40F (4.4C) or below, I'd say that is normal.

 

[Bill Roosa]

Hey David
What ya gots there is that exhaust "smoke" that comes from the fact that diesel fuel burnt with oxygen produces water and CO2. The water is in the form of water vapor and is initially very hot. As it travels down the exhaust tube it cools and when it hits the cold air outside the boat it condenses. If you look carefully you will note that this "smoke" does in fact disappear (evaporates in to water vapor again) and not go drifting off over the water dissipating, but not disappearing as it goes.
This is the same stuff you get out of your car tailpipe on cold mornings.
To convince yourself this is not a problem take note of the weather and when you get the most "smoke" You get on cool damp mornings (like your car) but not on sunny hot dry afternoons.
Having a small engine and a long exhaust tube cooled by water only makes the effect more pronounced.
Don’t worry, be happy.
BTW we get this type of post (you guessed it) every spring when the weather is cool and damp. Welcome to the club and when are you considering biting the bullet and entering the ranks of the Frostbite series participants.