I have an 83 Hunter 31 with a 2GM 13 horse engine. The mounts are footed on angle steel of 1/4 inch dia. I have big vibration for 200 rpm range at 1400 to 1600 rpm. I can place my hand on the alternator and calm the vibration. Has anyone tried to cure a similar problem by adding a half inch plate on top of the present mounts, welding, and bracing the mounts underneath. I am looking for a way to cure the problem without making new platforms and buying $400 worth of new mounts. The vibration all but disappears at other rpms. Thanks, Jim McClung, S/V Drum.
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Probably need new mounts.
Jim: It is probably time for new mounts. These are about 25 year old and may have had fuel on them and they do get tired. The 2 cyl. engine is not the smoothest thing in the world either. Assuming that your engine is in alignment and your cutlass are in good shape you may need someone to examine the mounts to see if they are any good. It has been the advise of others on this website that you do not change the mounts out to a different brand (only use Yanmar mounts). This may be due to the fact that the engine is a little jumpy and they need that flexibility. You may also want to check your injectors, shaft and prop balance these are all things that can be problems.
Jim: It is probably time for new mounts. These are about 25 year old and may have had fuel on them and they do get tired. The 2 cyl. engine is not the smoothest thing in the world either. Assuming that your engine is in alignment and your cutlass are in good shape you may need someone to examine the mounts to see if they are any good. It has been the advise of others on this website that you do not change the mounts out to a different brand (only use Yanmar mounts). This may be due to the fact that the engine is a little jumpy and they need that flexibility. You may also want to check your injectors, shaft and prop balance these are all things that can be problems.
New PYI mounts
I just had to replace my mounts (don't ask, long painful story) and the hunter yard recommended the new PYI R&D marine mounts. According to the yard, they have had great experience with them, much sturdier, less vibration and actually a little cheaper than the Yanmar mounts. I haven't had a chance to try them out yet, but I did take a look at them over the week-end and they do look like a heavy duty piece of engineering.
I just had to replace my mounts (don't ask, long painful story) and the hunter yard recommended the new PYI R&D marine mounts. According to the yard, they have had great experience with them, much sturdier, less vibration and actually a little cheaper than the Yanmar mounts. I haven't had a chance to try them out yet, but I did take a look at them over the week-end and they do look like a heavy duty piece of engineering.
Small world, eh?
Jim, My 37 Hunter had a similar engine when new in 1979, and the original owner fought with Hunter for a year to try and fix the excessive vibration problems. He finally gave up fighting and, being an engineer and slightly anal, took out the old/new engine and put in a three cyclinder 3HM which solved the problem and boosted the power. I inherited his fix, which seemed pretty extreme, but I can tell you he never found a cure in the early 80s despite looking hard. He tried replacing the mounts but it did not help. (Doesn't Modesto seem like a thousand years ago???) Cheers Sanders s/v Good News Alameda and Camp Connell
Jim, My 37 Hunter had a similar engine when new in 1979, and the original owner fought with Hunter for a year to try and fix the excessive vibration problems. He finally gave up fighting and, being an engineer and slightly anal, took out the old/new engine and put in a three cyclinder 3HM which solved the problem and boosted the power. I inherited his fix, which seemed pretty extreme, but I can tell you he never found a cure in the early 80s despite looking hard. He tried replacing the mounts but it did not help. (Doesn't Modesto seem like a thousand years ago???) Cheers Sanders s/v Good News Alameda and Camp Connell
Same problem - Resolved
I had exactly the same problem with my 2GM. The mounts appeared fine to me, but the mechanic found one was actually broken. With that replaced (new Yanmar mount) the problem was cured.
I had exactly the same problem with my 2GM. The mounts appeared fine to me, but the mechanic found one was actually broken. With that replaced (new Yanmar mount) the problem was cured.
My new 2YM15 has a similar vibration
Its a bit of a disappointment. After talking with Yanmar I added shim plates under the mounts to make the motor sit lower on the mounts. A lot of work for no results. I seem to be getting used to it, and avoid running at that rpm range.
Its a bit of a disappointment. After talking with Yanmar I added shim plates under the mounts to make the motor sit lower on the mounts. A lot of work for no results. I seem to be getting used to it, and avoid running at that rpm range.
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