WHITISH SMOKE

[keller]

YANMAR 3 CYLINDER SMOKES AT HIGH RPM (2700) BUT OK
LOWER ---ANY SUGGESTIONS???

Check this thread first
http://cruisersforum.com/showthread....&threadid=2811
If no answers there, how about some more details. Hours on the engine? Operating temp at that RPM? that sort of thing.

[keller]

FEW HOURS, TEMP UNKNOWN LIGHT WARNING NO GAUGE
WARNING DOES NOT POPUP OR LIGHT. IN ALL REPECTS BUT FOR THE SMOKE RUNS WELL AND STARTS GOOD

If it was a Perkins, I would say it was normal, but I have never had a Yanmar do this at that RPM. The checks you should do are outlined in the aforementioned thread. I strongly recommend installing a temp guage, as the guage will tell you in advance of developing problems. Slight differences in average operating temp can mean an impeller is going well before it quits.
So in your case, it could be any number of things. what diagnostics have you done so far?

[Alan Wheeler]

Hi Keller, two things. Could you repost this up in the Marine engines subject heading. There are some experianced guy's here that could help and they may overlook this heading on electrical.
Plus, is it possible the White smoke is just steam from the wet exhaust?

Wheels, I was going to make the same suggestion, but it occurs to me that if it is not smoking at lower RPM the only way it would produce steam at the higher RPM is if the engine temp is increasing. This would indicate another problem. The engine should not get appreciably hotter at this RPM unless there is a problem. This could be as simple as the boat being over proped, or the impeller being in the early stages of failure. I think some additional diagnostics are definitely in order.

[Alan Wheeler]

Low RPM is simply not going to produce enough hot exhaust to evapourate the cooling water. As the RPM increases, so does the exhaust gases and the exhaust heatand what's more, the engine is now getting rid of more internal heat and so adding to the temperature of the cooling water. Thus you tend to see more steam at higher RPM than lower.

This engine produces about 25hp at 2500 RPM, and approx 26 at 2700RPM. The torque curve starts to drop at anything over 2500 RPM. The continuous rating is 3489 RPM, where it produces 27.1 hp. As it is operating at only about 80% of it's horsepower, and 80% of it's operating RPM, it is unlikely that you would see any appreciable change in operating temp between 2500 RPM and 2700 RPM. Going by the information that was provided, I am working on the assumption that the engine does change at 2700 RPM + or - 50 RPM. If the boat is over proped, it is posible that when the torque begins to drop off above 2500 RPM, the engine may be producing more heat. The specific reference to the higher RPM is what leads me to believe that this is not simply condensation. Condensation will produce steam at lower RPM, in the range of 1500, and would not change visibly between 2000 and 2700 RPM.

[Alan Wheeler]

I am not actually suggesting a change as such. What I am suggesting is that for other reasons like more exhaust gas pressure/volume, angle of boat, Venus aligning with Jupiter etc etc, it is just being more visual at the higher RPM. Hence it was just a suggestion. Much more info is required and also, hence why I suggest this goes up to the engine department. One, there is a lot on this subject up there already and two,if it truns out to be something different than what is already written up there, then it will be sad if this gets lost down here.

Point taken.

[keller]

REFFERING TO THE YANMAR WHITISH SMOKE ONE OF FOUR THINGS MAY BE TAKING PLACE ( OR A COMBINATION) 1.- WATER IN THE COMBUSTION CHAMBER. 2.- JUST PLAIN STEAM AS A PRODUCT OF HIGHER RPM OPERATION. 3. BROKEN OR FROZEN OIL PISTON RING & 4.- FUEL DELIVERY PROBLEMS BE IT AT THE INJECTOR OR PUMP LEVEL.

OF ALL THE ABOVE MY MAIN WORRY IS WATER INSIDE THE COMBUSTION CHAMBER. MY YANMAR 3GM30 IS RAW WATER COOLED, APART OF SUGGESTIONS ON ALL POINTS IS THEIR ANY WAY I CAN DETERMINE IF THE SMOKE IS WATER VAPOR?

[Alan Wheeler]

Hi Tony, firstly, would you mind turning your "CapsLock" off. Typing in Captal letters is like yelling on the internet.

Up in the "engine" topic, this subject has been discussed many times before. Take a look through that area.
But just to overview some of what you will find up there. It is most unlikely you have a problem unless there are other factors involved. Like hard to start. When it starts, one cylinder will not fire for awhile. Lack of power and not making max RPM. Blue smoke issues. Black smoke issues. Deisel on the water surface.
Engine overheating.
If you have none of these issues, then chances are, it is just plain steam.
Don't panic. Deisels tend to go or not go. There are very little "inbetween" issues with Deisel. A fault has a huge factor on combustion with a Deisel. There are many questions to pose. But I suggest you go take a read of some really good advice given by some clever people on here. Then feel free to ask further questions if you need.

[keller]

wheels, will do
tony

[Talbot]

My first thought with white smoke is that you may have a blocked inlet pipe (crustaceans, weed debris etc.) or that the impellor is damaged. Both relatively easy to check.

[keller]

Apparently white smoke may be excess diesel which differs from partially burned diesel (black smoke). However, talbot's suggestion is right on the money white smoke, if water vapor, could be a product of evaporation once engine temp. increases through water starvation. Tomorrow I'll give it a run.

Defnitely a temp. gauge should be installed. How's that to say the obvious.