At idle there should be really no visible smoke. A little light gray or very wispy whitish gray during engine warm-up, but nothing resembling bluish/black belching smoke.
Also if you run your motor hard and push your boat into heavy chop or wind, your working your diesel and you will get some black smoke or soot on the transom, no matter how clean your injectors are. Also, any fouling on the prop will cause the motor to work harder and result in more smoke. Any pinhole leaks in your fulel line (air) will add smoke. As long as it isn't noticeable at idle or belching smoke under high load, bluish, very white, or very black smoke, I would n't worry about a little smoke.
05-14-2012 02:10 PM
Re: Diesel Engine Smoke
It's not unusual to see some 'warm water mist' but that's water vapour and should quickly dissapate - and would be more likely in cooler climes.. on a good engine with clean injectors there should be little if any smoke of any sort. I've noticed that since we had our injectors serviced this past winter, the 'soot smudge' on the boat is much reduced even though we never really had any visible smoke to speak of.
But it seems no matter what, when the exhaust blows into the cockpit downwind it still stinks....
05-14-2012 02:05 PM
Diesel Engine Smoke
What is the normal exhaust for a marine engine? Should there be visable exhaust when engine is warmed up and ideling? When the engine is warm and running at high rpm and nearly full output should there be any visible engine exhaust, if so what color. I know black exhaust is bad (overloaded engine) and blue smoke may indicate burning oil, but what is a normal color if any at all? Would you normally see visible water mist from the sea water cooling coming out of exhaust?