my yanmar 16 will trigger the overheat alarm if I rev above 2300rpm ,should that be a concern??? If I run it @2200-2300 it'll run all day w/o alarm.
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Tom Long
Overheating
We had a similar problem a few years ago. It turned out to be the heat exchanger, which was suffering from mineral buildup. We had it cleaned and have had no problems since. The Yanmar should easily run all day at 3200 rpm.
We had a similar problem a few years ago. It turned out to be the heat exchanger, which was suffering from mineral buildup. We had it cleaned and have had no problems since. The Yanmar should easily run all day at 3200 rpm.
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hp
It could be other things
There is all kinds of advice in the Archives on this. Could be low on coolant even if your overflow tank looks good. Could be a bad impeller. Could be the mixing elbow is coked up, which happens a lot on Hunters.
There is all kinds of advice in the Archives on this. Could be low on coolant even if your overflow tank looks good. Could be a bad impeller. Could be the mixing elbow is coked up, which happens a lot on Hunters.
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Les Andersen
Overheat
Steve, An easy check on the elbow, which I will bet is your problem, is to just remove the hose and clean out the fitting with a nail or other similar tool. Costs you nothing. It won't fix the problem permantly but will work until it cokes up again. There have been literally hundreds of posts on this over the past years. Good Luck Les s/v Mutual Fun
Steve, An easy check on the elbow, which I will bet is your problem, is to just remove the hose and clean out the fitting with a nail or other similar tool. Costs you nothing. It won't fix the problem permantly but will work until it cokes up again. There have been literally hundreds of posts on this over the past years. Good Luck Les s/v Mutual Fun
I v ote for the mixing elbow too!
I'd vote for the mixing elbow too. But you really need to check out the impeller and the heat exchanger too. I think that you easily remove the front cover on the heat exchanger. Then get some long q-tips and run them thru the exchanger. This should give you an idea if it needs to be cleaned out. To check out the mixing elbow you really need to R/R the unit.
I'd vote for the mixing elbow too. But you really need to check out the impeller and the heat exchanger too. I think that you easily remove the front cover on the heat exchanger. Then get some long q-tips and run them thru the exchanger. This should give you an idea if it needs to be cleaned out. To check out the mixing elbow you really need to R/R the unit.
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Rich Wallace
Help with the mixing elbow
Steve, I posted a note on the big boat forum a couple of weeks ago which may also be of interest to you. If the Yanmar has a cast elbow that is threaded into a nipple that threads into the exhaust manifold, read on. The thread from the nipple to the elbow is left handed. You have to turn in clockwise to loosen it rather than counter clockwise. The thread from the nipple to the manifold is a right handed thread. I have not figured out exactly why it was manufactured this way (I think is was so the outlet of the elbow could be lower than the manifold casting) but it caused me to do a lot of extra work until I discovered the problem.
Steve, I posted a note on the big boat forum a couple of weeks ago which may also be of interest to you. If the Yanmar has a cast elbow that is threaded into a nipple that threads into the exhaust manifold, read on. The thread from the nipple to the elbow is left handed. You have to turn in clockwise to loosen it rather than counter clockwise. The thread from the nipple to the manifold is a right handed thread. I have not figured out exactly why it was manufactured this way (I think is was so the outlet of the elbow could be lower than the manifold casting) but it caused me to do a lot of extra work until I discovered the problem.
Thanks Rich.
Rich: I posted an article in the Photo Forum about changing out the Mixing Elbow on my H'31. One of the things that I had pointed out was that there was a reverse thread on the coupling. I think the reason for this is the fact that when you are putting the thing together, you needed to have a way to adjust the angle of the elbow in relationship to the manifold. I do not think (that is what my wife says anyway) that you would be able to adjust this angle of the coupling had the same thread on boat sides. (this is just my best guess)
Rich: I posted an article in the Photo Forum about changing out the Mixing Elbow on my H'31. One of the things that I had pointed out was that there was a reverse thread on the coupling. I think the reason for this is the fact that when you are putting the thing together, you needed to have a way to adjust the angle of the elbow in relationship to the manifold. I do not think (that is what my wife says anyway) that you would be able to adjust this angle of the coupling had the same thread on boat sides. (this is just my best guess)
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