I spent 6 days this past week sailing the Chesapeake bay and had a great time except for some engine problems. Every day after the first day I had the same thing happen. After mtoring along at moderate rpm's (2400-2800) I had the sudden onset of the engine running rough and off white smoke coming out of the exhaust. On each occasion I throttled down the engine and the problem went away immediately. The engine did not overheat. On each occasion I was able to continue at a lower rpm with no problem. After it happened a few times I would lower the rpms, the problem would go away and would then go back up on the rpms and hav e no problem- at least for a good while. I called my mechanic who suggested that there was water in the fuel and to empty the bowel on my racor fuel filter. I did that but did not see any water. I also added some water absorber and filled the tank up. It happened several more times after doing that. On the last day that we were out it happened two more times but did not seem as bad. The last time it happened I did not do anything and it lasted just a short time and went away without changing the rpms. I also noted a small oil leak from the oil pan seal and a small water leak at one of the hose fittings. The oil level was a little on the high side. I did note that the fresh water tank was a little low and filled it. Whe I ran the engine the next time after it warmed up some water squirted out of the vent on the overflow tank. I had trouble with my engine overheating last year and replaced the mixing elbow, thermostat, water tank pressure cap and cleaned the cooling tubes and exhaust manifold. The raw water flow seems to be good. My mechanic said he did not think it was the head gasket because it was not overheating. My engine is a yanmar 3GM30F-1987 vintage with regular maintenance. Any help would be appreciated.
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Try this forum for marine diesel engines
The link below is a really good forum for yanmar engines. I know the issue of white smoke has been discussed there (link below). You might want to go there and do a search for "white smoke".
The link below is a really good forum for yanmar engines. I know the issue of white smoke has been discussed there (link below). You might want to go there and do a search for "white smoke".
A word about water absorption additives.
Several guys here have said do not use water absorption additives. The stuff will hold the water in suspension and let it get past your filter/separator. Then when it reaches the pump and injectors, well, bad things happen. I would guess that most of the bad stuff happens after shut down when the boat is unused. You should be fine though because no water was in your filter, but I wouldn't use the stuff again. Makes too much sense.
Several guys here have said do not use water absorption additives. The stuff will hold the water in suspension and let it get past your filter/separator. Then when it reaches the pump and injectors, well, bad things happen. I would guess that most of the bad stuff happens after shut down when the boat is unused. You should be fine though because no water was in your filter, but I wouldn't use the stuff again. Makes too much sense.
white diesel smoke
white smoke diesel smoke should be black! If you have white smoke, that's a sign of water getting into your combustion chamber. When your engine acts up like you said it did I would suspect you have a blown head gasket. Have someone do a compression test and that should tell you something.
white smoke diesel smoke should be black! If you have white smoke, that's a sign of water getting into your combustion chamber. When your engine acts up like you said it did I would suspect you have a blown head gasket. Have someone do a compression test and that should tell you something.
Thanks for your input. My mechanic said that he did not think it was the head gasket because it was not over heating, it went away quickly when I decreased the rpms and went away the last time without doing anything. Whot do you think? wht about a clogged injector? Thanks.
The white smoke indicates that you have a one way head gasket leak. Your mechanic should inspect it before saying that it is not a head gasket leak. This is a common problem on this type engine. When was the last time the head was retorqued down? The head bolts do strecch on these engines and requires that they be retorqued down as a normal amintenance item. You may be able to retorque it down and it will go away. If it were a clogged injector the engine would miss and lose power. Have more than thirty years experience with marine engines. From very large to small. Check it out before it blows all together. Joe Dougan
White smoke could be steam from the elbow
I know you replaced the elbow last year, but won't hurt to check it again. It sure sounds like a U-elbow problem, or a head gasket. White smoke could be the water in the U-elbow turning into steam because the elbow is plugged with carbon. Maybe there is just enough of a path for some water to get through at low RPM, but at high RPM, the path is just not big enough and can not keep up, and the engine overheats, and the water turns to steam. How about trying this. Remove the hose from before the heat exchanger and after the u-elbow. You should be able to blow through it without any restrictions. It may take some effort initially in order to empty out the existing water in the exchanger tubes.
I know you replaced the elbow last year, but won't hurt to check it again. It sure sounds like a U-elbow problem, or a head gasket. White smoke could be the water in the U-elbow turning into steam because the elbow is plugged with carbon. Maybe there is just enough of a path for some water to get through at low RPM, but at high RPM, the path is just not big enough and can not keep up, and the engine overheats, and the water turns to steam. How about trying this. Remove the hose from before the heat exchanger and after the u-elbow. You should be able to blow through it without any restrictions. It may take some effort initially in order to empty out the existing water in the exchanger tubes.
water
Along with white smoke (really steam)symptoms of a head gasket leak could include having to add water/coolant because it is leaking from the water jacket into the combustion chamber. Also bubbles or pressure in the cooling system which might cause water to squirt out of the overflow tank. If you have a radiator pressure tester you could put it on and see if the pressure goes up when the engine is started which could indicate a leak between the combustion chamber and coolant. Also, if your oil level was high, as you mentioned, that could indicate water getting into the oil. Is the oil at all milky looking on the dip stick? Just some thoughts.
Along with white smoke (really steam)symptoms of a head gasket leak could include having to add water/coolant because it is leaking from the water jacket into the combustion chamber. Also bubbles or pressure in the cooling system which might cause water to squirt out of the overflow tank. If you have a radiator pressure tester you could put it on and see if the pressure goes up when the engine is started which could indicate a leak between the combustion chamber and coolant. Also, if your oil level was high, as you mentioned, that could indicate water getting into the oil. Is the oil at all milky looking on the dip stick? Just some thoughts.
The oil did not appear milky. I think I will try torquing the head gasket bolts. If I open the pressure cap on the water tank and start the engine would bubbles indicate a problem with the head gasket? Thanks again.
You need to be sure...
if it is steam or smoke. Steam will rise and dissipate quickly once it hits the cooler outside air, smoke will tend to linger. Each represents a different type of problem. "White smoke usually occurs when there is not enough temperature to burn the fuel. The unburned fuel particles are then exhausted usually by a rich fuel smell. In cold weather it is not uncommon to get white smoke until engine temperature builds up. Low engine cranking speed can also create an excessive amount of white smoke. If the problem persists after the engine is up to operating temperature several other things should be checked. A faulty injector can cause white smoke. Timing is often a factor when white smoke is excessive. Low engine compression can cause the problem and the injection pump can also have problems that result in white smoke. Air in the fuel system can also result in white smoke. Lastly steam cause by a head gasket or other water leak into the combustion system can disguise itself as smoke. Steam will dissipate rapidly being once it hits lower temperature ambient air while smoke will persist and hand in the air."
if it is steam or smoke. Steam will rise and dissipate quickly once it hits the cooler outside air, smoke will tend to linger. Each represents a different type of problem. "White smoke usually occurs when there is not enough temperature to burn the fuel. The unburned fuel particles are then exhausted usually by a rich fuel smell. In cold weather it is not uncommon to get white smoke until engine temperature builds up. Low engine cranking speed can also create an excessive amount of white smoke. If the problem persists after the engine is up to operating temperature several other things should be checked. A faulty injector can cause white smoke. Timing is often a factor when white smoke is excessive. Low engine compression can cause the problem and the injection pump can also have problems that result in white smoke. Air in the fuel system can also result in white smoke. Lastly steam cause by a head gasket or other water leak into the combustion system can disguise itself as smoke. Steam will dissipate rapidly being once it hits lower temperature ambient air while smoke will persist and hand in the air."
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