I have a Yanmar 1GM that produces smoke that blackens the transom, and causes low RPM. I have repalced both fuel filters, the entire exhaust system, the fuel, and some of the hoses (The ones that looked like a possible cause). With the new fuel I added a diesel treatment. I was thinking that the fuel pump is the logical next step?? Has anyone seen or experienced similar problems?
- Status
- Not open for further replies.
R
Ray Bowles
Black smoke can be from overuse.
Frank, Black soot can be the result of over working the engine. This can be from extended full power running, a fouled bottom, wrong or fouled prop, fouled injectors. Treatments usually won't clear this up. Mixing elbows etc usually only pass the problem down from the source and can be a costly repair when the problem is upstream. Our 50hp Yanmar will do the same to some extent if I run her at full power when the boat is fully loaded. 25,000# dry vs. 29,000 or more when leaving for the year and my bottom, prop and injectors are perfect. Ray
Frank, Black soot can be the result of over working the engine. This can be from extended full power running, a fouled bottom, wrong or fouled prop, fouled injectors. Treatments usually won't clear this up. Mixing elbows etc usually only pass the problem down from the source and can be a costly repair when the problem is upstream. Our 50hp Yanmar will do the same to some extent if I run her at full power when the boat is fully loaded. 25,000# dry vs. 29,000 or more when leaving for the year and my bottom, prop and injectors are perfect. Ray
R
Ron Vanderveer
Good news and Bad news
Frank My co-owner and I just went through similar problems with our 20 year old 1GM in our Hunter 27. If you have the technical ability and tools to check the compression, that would be my next recommended step. Or get a mechanic out that can do it. Our similar problems turned out to be a cracked head. The mantra on diesels is fuel, fuel, fuel, which I believe is true. However, on a raw water cooled, twenty year old diesel, if you have eliminated the fuel possibilities, it might be a bit more complicated and expensive. See the long version of our story below. Good luck! After 2 months trying to fix what we thought was a fuel problem and becoming very frustrated, we called in the local experts. The first visit resulted in a new mixing elbow and general "tune up", and the engine ran well for about 8 motths after that. But we still were having quite a bit of black soot on the transom, and performance seemed a little less than it should have been. Then we had a fuel tank leak problem, and replaced the tank, which was not related to our engine problems. The reason I mention it is that this reinforced the idea that it was not a fuel issue, at least from a fuel quality standpoint. Not too long after that, the engine began to get picky about starting. Finally, one day, it just wouldn't start (luckily we were in our home slip at the marina that day!). We coaxed it to life with much difficulty, and once it had run for a few minutes it would start again right away. But if we left it for a couple of hours or so, it would refuse to start again. So the mechanic was called again, and he did check everything that you listed in your post. Finally he brought out the compression tester and realized that the compression was low. He removed the head and took it to the shop to be cleaned and tested, and sure enough it had one large crack near where the mixing elbow connected, but also one very critical hairline crack inside, which was causing the compression loss. Bottom line: $1200 repair including labor, but she runs like a dream now! Take care, Ron
Frank My co-owner and I just went through similar problems with our 20 year old 1GM in our Hunter 27. If you have the technical ability and tools to check the compression, that would be my next recommended step. Or get a mechanic out that can do it. Our similar problems turned out to be a cracked head. The mantra on diesels is fuel, fuel, fuel, which I believe is true. However, on a raw water cooled, twenty year old diesel, if you have eliminated the fuel possibilities, it might be a bit more complicated and expensive. See the long version of our story below. Good luck! After 2 months trying to fix what we thought was a fuel problem and becoming very frustrated, we called in the local experts. The first visit resulted in a new mixing elbow and general "tune up", and the engine ran well for about 8 motths after that. But we still were having quite a bit of black soot on the transom, and performance seemed a little less than it should have been. Then we had a fuel tank leak problem, and replaced the tank, which was not related to our engine problems. The reason I mention it is that this reinforced the idea that it was not a fuel issue, at least from a fuel quality standpoint. Not too long after that, the engine began to get picky about starting. Finally, one day, it just wouldn't start (luckily we were in our home slip at the marina that day!). We coaxed it to life with much difficulty, and once it had run for a few minutes it would start again right away. But if we left it for a couple of hours or so, it would refuse to start again. So the mechanic was called again, and he did check everything that you listed in your post. Finally he brought out the compression tester and realized that the compression was low. He removed the head and took it to the shop to be cleaned and tested, and sure enough it had one large crack near where the mixing elbow connected, but also one very critical hairline crack inside, which was causing the compression loss. Bottom line: $1200 repair including labor, but she runs like a dream now! Take care, Ron
Before you do anything drastic...
... please follow Ray's suggestions. Have someone dive your boat and check for something wrapped around the prop shaft.
... please follow Ray's suggestions. Have someone dive your boat and check for something wrapped around the prop shaft.
S
Steve G
Frank
You didn't mention changing the air filter. Did you do that? Also, My 2GM (13 HP in a 33' Hunter) blackens the underside - probably because I have to run it @ 2800 RPM to get 4.5 Kts out of it - Grossly underpowered and definitely used hard.
You didn't mention changing the air filter. Did you do that? Also, My 2GM (13 HP in a 33' Hunter) blackens the underside - probably because I have to run it @ 2800 RPM to get 4.5 Kts out of it - Grossly underpowered and definitely used hard.
F
Frank
Neglected to include...
Yes, I did try the air filter, and the mixing elbow. Sorry I neglected those. If the injectors are fouled and cleaners won't help, what would the next step be?
Yes, I did try the air filter, and the mixing elbow. Sorry I neglected those. If the injectors are fouled and cleaners won't help, what would the next step be?
R
Ray Bowles
Injector repair
Frank, this is Ray again. Injectors can be rebuilt and calibrated fairly easly. The best thing you can do is to talk to a local diesel repair shop in your area. It does not have to be a marine shop so the prices could be much lower with all the automotive diesels today. ask the shop about calibrating your injector pump and rebuilding/cleaning your injectors. They can give you a fairly close price. This is based on your ability to remove/install the parts and bleeding the system. The results could be very impressive. I am assuming that your bottom & prop are clean etc and Compression is good. Since many marine engines are not run on frequent basis they can gum up during long inactive periods and can lead to problems such as yours. Since you say that rpm's are low that eliminates simply running the engine at a lower settings. If I can be of any further help I'm in the Catalina owners directory. Ray
Frank, this is Ray again. Injectors can be rebuilt and calibrated fairly easly. The best thing you can do is to talk to a local diesel repair shop in your area. It does not have to be a marine shop so the prices could be much lower with all the automotive diesels today. ask the shop about calibrating your injector pump and rebuilding/cleaning your injectors. They can give you a fairly close price. This is based on your ability to remove/install the parts and bleeding the system. The results could be very impressive. I am assuming that your bottom & prop are clean etc and Compression is good. Since many marine engines are not run on frequent basis they can gum up during long inactive periods and can lead to problems such as yours. Since you say that rpm's are low that eliminates simply running the engine at a lower settings. If I can be of any further help I'm in the Catalina owners directory. Ray
- Status
- Not open for further replies.