I'm looking at a Hunter 33. When the Yanmar idles, there is a reasonable amount on motor movement on the mounts. Is that normal?
Thanks
Thanks
Engine vibration
- Thread starter taddemilly
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It depends on your meaning of "reasonable". There will be a slight vibration, but if there is a lot of movement, then the engine mounts mat be loose or defective. It could be where the engine bolts to the "mounts" or where the "mounts" are lag bolted into the stringer under the fiberglass. If it's the lag bolts, they may have chewed uo some of the wood in the stringer. If thats the case, you can remove the lag bolts and put in some "Get Rot" epoxy with some oak slivers mixed in with it. Cut some slim oak strips and put 3 or 4 of them into the hole. Then add the "Get Rot" mix into the hole and insert the lag bolt (apter spraying it with "Pam" or some mold release), and bolt it down snug. The oak strips give the lag bolts something to bite into. Give the epoxy time to fully cure, then run the engine. It should be quite secure. If, of course, its the joint between the engne and the mount, you can just tighten it or replace the engine mounts.
I had the severe vibration problem and did the first fix to the lag bolts. Some 4 or 5 years later it is still tight. In my case it was only one lag bolt (Fwd - Port lag bolt).
Hope this is somewhat helpful.
Dick, S/V Puffin 1990 H-33.5
I had the severe vibration problem and did the first fix to the lag bolts. Some 4 or 5 years later it is still tight. In my case it was only one lag bolt (Fwd - Port lag bolt).
Hope this is somewhat helpful.
Dick, S/V Puffin 1990 H-33.5
I'm so new to this, I don't have anything to compare it with. The engine is new to the boat (380 hours) since installed. I did not see any leakage around the packing nut, although the shaft was moving, too.
Thanks again.
Thanks again.
It could still be some where in the engine mount system, or it could be alignment between engine and shaft.. If the engine mounts seem OK, then loosing the mount bolts and realligning the engine to the shaft may be the key. But, I don't have any experience with doing allignment. Many others on this site do though, and can help a lot.
Dick
Dick
What engine is it? The engine in my boat, a 2QM20, has a reputation for vibration. And it does (vibrate). That said, when I'm running my engine, the movement has a null spot at the shaft output from the transmission. I can't visually detect any movement at the shaft.
But the other tips already given are valid. The engine does have to be firmly adhered to the boat through the motor mounts. I also had to repair this when I bought my boat. The fiberglass for the lag bolts connecting the motor mounts into the stringers had stripped and no longer could be tightened firmly. My method, similar to Dick/Navigator97 was to remove the bolts, wrap them with telfon tape, then covered over with an anti-sieze wax to be sure. Then inserted west systems epoxy into the holes with throug a small plastic hose connect to syringe. The screwed in the lag bolts to the point where before they would begin feel they wouldn't grip any further. Still holding tight after 3 years and 250 hours.
But the other tips already given are valid. The engine does have to be firmly adhered to the boat through the motor mounts. I also had to repair this when I bought my boat. The fiberglass for the lag bolts connecting the motor mounts into the stringers had stripped and no longer could be tightened firmly. My method, similar to Dick/Navigator97 was to remove the bolts, wrap them with telfon tape, then covered over with an anti-sieze wax to be sure. Then inserted west systems epoxy into the holes with throug a small plastic hose connect to syringe. The screwed in the lag bolts to the point where before they would begin feel they wouldn't grip any further. Still holding tight after 3 years and 250 hours.
It's a Yanmar 2GM20F. Before (and if) I buy the boat, I'll sure look at the points made. Thank you for your ideas!
Most diesel have a idle vibration that goes away as speed increases. So some vibration is normal. Still the mounts and related hardware need to be checked. Most surveyors should be able to give you an opinion or get a separate engine survey from a reputable mechanic. It could be something as simple as the idle is set to low. Assuming the mounts were new when the engine was replaced 380 hours ago not much chance it is major unless something happened or there was a installation problem. Best bet is have a mechanic look at it if you are not sure.
hmmmm.... Sounds famailiar
I was about to post a question regarding just how much vibration and shaking is considered "allowable". I've got a 2QM15 in a 79 H33 that, by my untrained eye, seems to be shaking a lot.... not just at idle.
I wonder if this could be casuing the thumping noise from the drive shaft as well. I was suspecting theengine was out of alignment, but now I'm thinking it might be time for new mounts as well.
How hard a job is all that, or should I leave it to the mechanics?
I was about to post a question regarding just how much vibration and shaking is considered "allowable". I've got a 2QM15 in a 79 H33 that, by my untrained eye, seems to be shaking a lot.... not just at idle.
I wonder if this could be casuing the thumping noise from the drive shaft as well. I was suspecting theengine was out of alignment, but now I'm thinking it might be time for new mounts as well.
How hard a job is all that, or should I leave it to the mechanics?
The vibration at idle on the GM engines is quite often caused by a low idle speed. You can check this out by just reving the engine 100-200 rpms.
When the boat is surveyed, you should point out ANYTHING that you want to have the surveyor focus on. You should also check out the boat reviews for the model that you are looking at to see if there are any inherent problems with this specific model.
What year/model are you looking at?
When the boat is surveyed, you should point out ANYTHING that you want to have the surveyor focus on. You should also check out the boat reviews for the model that you are looking at to see if there are any inherent problems with this specific model.
What year/model are you looking at?
If you purchase the boat and it needs new mounts DO NOT get tricked into purchasing non-Yanmar mounts. They are specifically engineered for these motors and are different for the forward and aft mounts. As a matter of fact, it may be that the group that installed the new engine may have used aftermarket mounts or installed them in the wrong position.
Had a similar issue on my 82 H-33 with a 2GM yanmar. We tightend the alternator belt and the vibration went away.
GM series mounts are very soft. The engine will move quite a bit. One thing I have seen in engine installations is the installer mixing up the mounts. The front and rear mounts are drastically different in hardness, but look identical. If mixed up, they will cause LOTS of vibration.
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