SeaRay 440 Express BLACK SMOKE in aft deck

[Gibsri]

I cruise at 1500-2000 RPM and at that speed, I get a ridiculous amount of black smoke in aft deck. If i go below 1200. or above 2200, there is mo smoke. I have had a mechanic look at it and they tell me there is NOTHING wrong with injectors, engine etc and it is simply that at that RPM it will smoke. Anyone know any fixes?

 

[BurgundyS24]

I cruise at 1500-2000 RPM and at that speed, I get a ridiculous amount of black smoke in aft deck. If i go below 1200. or above 2200, there is mo smoke. I have had a mechanic look at it and they tell me there is NOTHING wrong with injectors, engine etc and it is simply that at that RPM it will smoke. Anyone know any fixes?

Is it coming from the engine(s) or exhaust? Could it be the "station wagon" effect?


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[Gibsri]

it is coming from exhaust. have had my mechanic check it out and they say I need to run above 2200rpm and there will be no problem. I want to run 1800-2000..... thinking possibly venting exhaust into water, but they say it can not be done

 

[NotHerDecision]

This would be a good question for the folks over at the boatdiesel forum. The short answer is black smoke is unburned fuel, but I'm not qualified beyond that.


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[Boatingnut]

Which Cat engines do you have? I didn't see that anywhere.....

 

[bigcam]

Not to be a smart a--, but you're trying to run the boat at a speed that it doesn't like. I'll bet the nose is high and the wake is huge. Simple solution, slow down or speed up. At that speed the motors are overfueling because turbos are not putting out enough boost. All planning hulls have this problem.

 

[aquadancer]

not allowing turbos to spool up results in excess fuel on a mechanical engine... too much fuel / not enough oxygen results in unburned fuel and black smoke