We just completed our first year with our 1991 37.5 Legend. I have read many of the comments on this web site regarding mixing elbow maintenance. We have experienced infrequent engine overheating at cruising RPM's (approx 2750) and have had black soot build up on the transom - both are possible indicators of a clogged mixing elbow. One of the things we have learned to do is to let the engine idle for several minutes and then run up to 3000 RPM's just before turning it off. This seems to help minimize the soot build up. Before undertaking the replacement of the mixing elbow, I am interested in finding out whether a boat that has spent its entire life in the great lakes and is generally on the hard with anti-freeze in the fresh water cooling system for 6-7 months per year, should have the same mixing elbow maintenance as a salt water boat. Does anyone have any experience here?
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Get a gasket and check it out.
Steve: Why don't you just get a gasket and remove the elbow for the peace of mind. I would have to agree with you that it is doubtful that you are going to find much build up. One of the main reasons for the build up is the presense of seawater (salt) and the hot exhaust gases. This is what really causes the coking effect. If you check it out, you will be able to eliminiate that as a potential overheating problem.
Steve: Why don't you just get a gasket and remove the elbow for the peace of mind. I would have to agree with you that it is doubtful that you are going to find much build up. One of the main reasons for the build up is the presense of seawater (salt) and the hot exhaust gases. This is what really causes the coking effect. If you check it out, you will be able to eliminiate that as a potential overheating problem.
Not sure.
But when I first began reading of the problem about five years ago I decided to check. It was not that difficult to remove the elbow from my 20 year old Yanmar. It also has always been in the Great Lakes and it was clean as a whistle. In the archives you will find a lot of information about cleaning it. If you find that too difficult you are close enough to Torresen to go pick up a new one.
But when I first began reading of the problem about five years ago I decided to check. It was not that difficult to remove the elbow from my 20 year old Yanmar. It also has always been in the Great Lakes and it was clean as a whistle. In the archives you will find a lot of information about cleaning it. If you find that too difficult you are close enough to Torresen to go pick up a new one.
I'd go through the whole cooling system
At that age it wouldn't hurt and it isn't much more work. Also take off the end of the heat exchanger to check that there is no debris there. (An impeller can shed vanes into it if you ever lost one or more.) The smoke and overheating may be unrelated. The injectors may need cleaning. Good luck. At least you have your's out of the water in the winter for all these projects;^ Rick D.
At that age it wouldn't hurt and it isn't much more work. Also take off the end of the heat exchanger to check that there is no debris there. (An impeller can shed vanes into it if you ever lost one or more.) The smoke and overheating may be unrelated. The injectors may need cleaning. Good luck. At least you have your's out of the water in the winter for all these projects;^ Rick D.
did it this year
I have an 1989 Legend 35.5 with a 3GMF Yanmar. I took the two day course at Mack Boring in NJ. Larry Berlin, the instructor, told me that since the boat was purchased used and there was no information regarding the mixing elbow replace the elbow. It turned out that it was pretty clean and I had no problems. However, the thought was to be sure rather than have an unpleasant surprise at the least opportune time. Overall cost was $300 for the elbow, connector,gasket and stainless bolts. Good luck.
I have an 1989 Legend 35.5 with a 3GMF Yanmar. I took the two day course at Mack Boring in NJ. Larry Berlin, the instructor, told me that since the boat was purchased used and there was no information regarding the mixing elbow replace the elbow. It turned out that it was pretty clean and I had no problems. However, the thought was to be sure rather than have an unpleasant surprise at the least opportune time. Overall cost was $300 for the elbow, connector,gasket and stainless bolts. Good luck.
Replaced mine this past spring
I have a 1992 37.5, and after experiencing some overheating during the 2001 season, we replaced our mixing elbow last winter while we had her out of the water for the winter. The elbow was pretty coked up. I do not know if fresh water would have resulted in less coke, but your symptoms sound pretty similar to the ones we were experiencing.
I have a 1992 37.5, and after experiencing some overheating during the 2001 season, we replaced our mixing elbow last winter while we had her out of the water for the winter. The elbow was pretty coked up. I do not know if fresh water would have resulted in less coke, but your symptoms sound pretty similar to the ones we were experiencing.
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