My Yanmar is starting to blow a little smoke which is most noticable when I gun the engine in reverse to stop the boat at the dock. There is also an light oily film being deposited on the surface of the water when this happens. Any advice on cause and remedy would be most appreciated.
- Status
- Not open for further replies.
B
Bill O'Donovan
Depends what color
Black means you're burning oil, white means you're burning water. I forget what the third color is. If it goes away, not to worry. In a related matter, the best advice I ever got on keeping the mixing bowl clear was to gun the engine to 3000 rpm for a few seconds upon straightening out of the slip. This blows out built-up carbon and lets the engine breathe better. Then be sure to come back down so you're not zooming out of the pier lanes.
Black means you're burning oil, white means you're burning water. I forget what the third color is. If it goes away, not to worry. In a related matter, the best advice I ever got on keeping the mixing bowl clear was to gun the engine to 3000 rpm for a few seconds upon straightening out of the slip. This blows out built-up carbon and lets the engine breathe better. Then be sure to come back down so you're not zooming out of the pier lanes.
C
Colin
Black smoke
It is black smoke that is being blown out. Going on Steves reply I guess this means I am burning fuel and if so, how do I correct this?
It is black smoke that is being blown out. Going on Steves reply I guess this means I am burning fuel and if so, how do I correct this?
E
Ed Schenck
Oil in water?
Black smoke is usually a cheap fix, probably a mixing elbow full of carbon. But that is not normally accompanied by oil in the exhaust. I would employ a mechanic.
Black smoke is usually a cheap fix, probably a mixing elbow full of carbon. But that is not normally accompanied by oil in the exhaust. I would employ a mechanic.
K
Kobi Maru
Mine was too
Mine began putting out black smoke while running at 3200 rpms. I asked the diesel mechanic and he said it is probably nothing to worry about. He thought it was the burning out and exhausting of the buildup in the exhaust system. He said most people tend to run diesels at too low an rpm. My 27 hp Yanmar is supposed to run at 2800 to 3200 rpm. If it has been operated much below this, it will tend to build up in the exhaust. When you operate at the higher rpm, the operating temperature is higher, and it burns the old buildup out. He said to be sure to run any diesel at the correct rpm. I hope this helps you out.
Mine began putting out black smoke while running at 3200 rpms. I asked the diesel mechanic and he said it is probably nothing to worry about. He thought it was the burning out and exhausting of the buildup in the exhaust system. He said most people tend to run diesels at too low an rpm. My 27 hp Yanmar is supposed to run at 2800 to 3200 rpm. If it has been operated much below this, it will tend to build up in the exhaust. When you operate at the higher rpm, the operating temperature is higher, and it burns the old buildup out. He said to be sure to run any diesel at the correct rpm. I hope this helps you out.
B
Bruce Hill
Black smoke
As mentioned, black smoke is fuel/carbon. You do not mention age/size of engine in your post. As mentioned in previous posts, this is OFTEN caused by carbon buildup in the elbow. This tends to be a sailboat malady due to the fact that we start our engines, drive out of the harbor at low RPMs, set the sails and shut it off. I can't comment on the sheen on the water, might be worthwhile getting somone to look at it. But any good mechanic will tell you that you periodically have to drive the crap out of it (literally) to get carbon out. A good 2hr run at 80-90% of max keeps mine clean. I am not a mechanic!
As mentioned, black smoke is fuel/carbon. You do not mention age/size of engine in your post. As mentioned in previous posts, this is OFTEN caused by carbon buildup in the elbow. This tends to be a sailboat malady due to the fact that we start our engines, drive out of the harbor at low RPMs, set the sails and shut it off. I can't comment on the sheen on the water, might be worthwhile getting somone to look at it. But any good mechanic will tell you that you periodically have to drive the crap out of it (literally) to get carbon out. A good 2hr run at 80-90% of max keeps mine clean. I am not a mechanic!
How hard do you run the engine.
Colin: How hard do you run the engine (normal cruising RPM)? You have your boat in freshwater, correct? The mixing elbow is really not a big problem in that environment like it is in salt water.
Colin: How hard do you run the engine (normal cruising RPM)? You have your boat in freshwater, correct? The mixing elbow is really not a big problem in that environment like it is in salt water.
C
Colin
Thanks to all!
Thanks to all for the great comments. I will run the bag off my Yanmar as I do tend to run it light just to clear the harbour and hoist sails before shutting it off. Failing that I will get a mechanic to investigate.
Thanks to all for the great comments. I will run the bag off my Yanmar as I do tend to run it light just to clear the harbour and hoist sails before shutting it off. Failing that I will get a mechanic to investigate.
B
Brian Peyton
Old diesels vs new diesels
There is a lot to be said for using an engine in the way it was designed. A lot of old diesels were designed to operate at low rpms. Many large generators still run at 1800 rpm. Some of the old large displacement single cylinder diesels would run at such a slow speed you could almost count the rpms. Newer motors are designed differently. When you pass an arrow-board on the highway and hear that little diesel buzzing along, it may be running at 3600rpm. It will do that day in and day out for months. Most of those are little Lombardini air-cooled diesels making about 7 hp. The power/torque curve on newer diesels with rated rpm of 3600 usually converges about 2600 to 3000 rpm. In other words they like to be run there. So go out an run the pants off that diesel! Maybe we should set up some round the bouys power races for sailboats! More cruisers would win and we'd have a good excuse for running the diesel at max rpm for a while!-)
There is a lot to be said for using an engine in the way it was designed. A lot of old diesels were designed to operate at low rpms. Many large generators still run at 1800 rpm. Some of the old large displacement single cylinder diesels would run at such a slow speed you could almost count the rpms. Newer motors are designed differently. When you pass an arrow-board on the highway and hear that little diesel buzzing along, it may be running at 3600rpm. It will do that day in and day out for months. Most of those are little Lombardini air-cooled diesels making about 7 hp. The power/torque curve on newer diesels with rated rpm of 3600 usually converges about 2600 to 3000 rpm. In other words they like to be run there. So go out an run the pants off that diesel! Maybe we should set up some round the bouys power races for sailboats! More cruisers would win and we'd have a good excuse for running the diesel at max rpm for a while!-)
- Status
- Not open for further replies.