Yanmar 2GM20 Mounts

xeitosaphil

xeitosaphil

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I think I need to replace my mounts, ( or so the Surveyor said on the sea trial survey ) due to excessive sideways movement. The propshaft oscillates at about 1800rpm. The engine is coming out next week as I want to work on the engine compartment so I should be able to see if the mounts have gone? or whether it is something else, possibly bent Shaft
( probably not as it is 1" S/S and only 1mtr long ), also prop balance, misalignment or cutlass? I intend to replace the cutlass as a matter of course anyway and also considered replacing the mounts while I was at it. I also plan to draw the shaft and have it checked for true, but if I need to replace the mounts, the cost of yanmar replacements ( £600.00 Quoted ) has made me look for other options. It has been suggested to me that I try R&D Super Mounts? ( which are Shear mounts )

I contacted them and they say they have had some good results with yanmar engines with either Compression Mounts or Shear mounts

The cost of 4 mounts complete with flexible coupling is only £200.00, which is a big difference?

Does anybody on the forum have any first hand knowledge of these mounts, or fitted them to a 2GM20?

I have looked at several threads on 2gm20 but don't seem to be able to find anybody that has fitted alternative mounts, with long term results?

I would be interested to hear of any comments or results, so I am to be prepared for the prospect of mounting replacement which I think is going to be on the cards anyway.
 
Standard Yanmar engine mounts are very soft, so if you are used to an engine with harder ones, e.g. a Bukh, you could see a dramatic change. There is an alternative harder Yanmar mount which IIRC is only used for the aft two. This could solve your problem if they prove to be unbroken.

My philosophy is to try the easy things first, then go for the more difficult/expensive if these make no difference. So:
1. Check alignment. There is a strong chance that misalignment is at the root of the problem
2. Check shaft straightness. No need to pull it, put a gauge on it where it is and rotate the prop.
3. Change cutless bearing and examine the shaft carefully for wear. A surprisingly small loss of metal can lead to vibration problems.
4. Lift the engine a little, a small block and tackle or even using a plank as a lever will be enough. If the engine mounts are broken you will be able to see the break. If they are very oily they may have softened, if they feel slimy then you may have to replace them.
 
A common failing on Yanmar mounts is delamination of the rubber from the steel frame, which is not obvious until you take them off.

However, follow the checks suggest above as you are taking the engine out, particulalry alignment as no point in replacing them if the problem is elsewhere.

If you do use new Yanmar mounts make sure you get a set as they are different hardness front and rear on some models. As an alternative consider PolyFlex from Austraia - Southern Cross Marine in Salisbury are the agents. Have heard good reports and the person who bought my Yanmar 1GM is using them in his installation - they look impressive.
 
Yanmar 2gm20 Mounts Update

Hi everyone thanks for your input, I have now got my 2gm20 out which is in the cockpit of the boat as she is still afloat.
The mounts look ok, not delaminated from the steel and in quite good condition I think but?, they do seem quite soft and allow easy movement from side to side with little pressure.Is there any way of checking the amount of movement a good mount should have?
Incidently I do have 75's at the gearbox end and 100's at the waterpump end ( I did wonder if I might have had the wrong mounts or had them fitted at the wrong ends but it would seem they are correct?
As you can see the engine and bearers need some work, I have now removed the steel bearers and intend to replace them with stainless steel so I have no need for future maintenance to them.
I am still in two minds as to whether I should replace the mounts ,as it would be far easier to do it now, rather than go all throught this again later? but am not sure what to replace them with? ( More of the same , R&D , or poly flex as suggested by others )

For now I will get on with cleaning out the engine bay and painting the bilge and organise more engine bearers.

Still open to suggestions at the moment.

Will keep you informed as to the outcome.
 
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It just so happens I have a pair of R&D mounts for a Yanmar 2GM 20.
They are firmer than the Yanmar mounts so you'd need to buy two more,
but still a big saving. PM if you're interested.
I like the wooden "crane"!
 
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Polyflex are still £87.11 +VAT and P&P. so not much cheaper.

If you are interested, you need Y2.5CTF shore rating 50.
 
yanmar mount options

Thanks Full Circle for the info , do you know of anybody that has fitted them?

What I am after is a comparison as to which is best, or if there is a better option than the proper Yanmar mounts which always seem to be problematic?
 
I've done that?

xeitosaphil said:
Thanks Full Circle for the info , do you know of anybody that has fitted them?

What I am after is a comparison as to which is best, or if there is a better option than the proper Yanmar mounts which always seem to be problematic?
Click to expand...

We have a couple of workboats with Yanmar 30's in and we use R&D mounts with very few problems. When the engines were new we used the original mounts but after a couple of seasons they need replacing and we use R&D's. Although R&D say they are an exact replacement that's not quite true because they are a slightly different design and need a bit of work on the holes to get them fitted to the engine bed bolts ~ but once fitted they tend to last better than the original Yanmar one's. As for vibration I haven't noticed any difference.

Peter.
TheBoatman
 
I had polyflex mounts fitted to a 2GM20 in 2005. Vast improvement over the Yanmar mounts and they don't rust. Very pleased...but they were still about £80/mount.
There is an article in PBO May 2009.
 
Yanmar 2GM20 Mounts Update

Hi all,

Thanks to all of you who have taken the time to contribute to my post, I have decided to try the New R&D Super Mounts mounts 800-037 which were recommended for my instalation, as I think most of my problems are mainly due to miss-alignment?

I may also be able to reduce low rpm vibration which effects yanmars by slightly increasing the idle speed a little, it may also help to be aware of not making quick drastic changes in engine revs, which could also contribute to engine vibration?

Time will tell and if needs must, I may have to replace them at a later date?

But for now with a New boat looking at a hefty upgrate to re - rigging, New Roller Reefing and mast compression issues and repair I will give these a try?

I am sure there will be other questions with my ongoing refit , and it never ceases to amaze me how good this forum is with members giving help to others in need for information.
 
Ricd said:
I had polyflex mounts fitted to a 2GM20 in 2005. Vast improvement over the Yanmar mounts and they don't rust. Very pleased...but they were still about £80/mount.
There is an article in PBO May 2009.
Click to expand...

Ressurecting an old old post. sorry. Im now leaning towards getting Polyflex. Which type do i buy for the same engine, 2GM20 (raw water). thank you. (if you know still)
 
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