Yanmar Engine Mounts 4jh3te

[Tomtom39]

Hi all
Just motored a round trip of around 60 hours and my yanmar could do with some new front mounts. They were due last season but did not get around to doing them. The engine is around 12 years old and done approx 1800 hours. They looked quite corroded and flaky so thought replacing would do!
I have purchased the r&d ones and they are actually like for like so all the holes match up and pretty much the same to look at. I know they are not genuine but the reviews were excellent and they were quite a lot cheaper,
When I removed the old ones I was surprised to see that both the front ones were rated at 200 when normally one side would be 200 and the other side should be 150. The new ones that I have purchased are based on 200 and 150 as per yanmar specification.
They were mounted and the alignment checked but now when I idle the engine I get small vibration but when running the engine up the vibration goes away and the engine runs smoother than ever.
I have tried tweaking the adjustment and it seems to improve when I loosen the top nut on the mount so it is not so tight! Is there any tips that anyone can shed.

The height of the engine is the same as before! So no change there

I believe it is something to do with the tightness of the top nut and maybe the way the bottom nut that the engine sits on is also too tight.

Has anyone got any advice or had similar issues???

Thanks

[Tomtom39]

Just noticed that the yanmar 4jh3te 75hp requires 200 rating all around! This might be the problem as I have put 200 one side and 150 the other

[neilpride]

Thats why Yanmar Mounts are so flexible, to mitigate the vibrations at low and idle , Yanmars dance a lot at idle, nuts need to be tight, could be the r&d ones are a bit tough and at idle you feel the vibrations more than with the yanmar mounts, try to separate the couplings in, prop and trany and see if the vibrations are gone, or tight the nuts really well in all the mounts and check... lag bolts need to be tight to, and if nothing mitigate the vibrations at idle, 1 live with it, or 2 replace mounts for something more flexible....

[YankeePSC34]

[QUOTE="Tomtom39;1302209"]

I believe it is something to do with the tightness of the top nut and maybe the way the bottom nut that the engine sits on is also too tight.
-unquote-

The nuts should be tightened to maintain the alignment of the engine. I understand that you have now two new R&D mounts @ front and two old Yanmar mounts @ aft? Could you explain why you expect less vibrations by this configuration?

[Tomtom39]

Hi Yankee
The front mount had split so needed replaced and the r&d ones are a lot cheaper but have good reviews
The back mounts are in good condition and are genuine yanmar parts

[YankeePSC34]

Hi Tom,
Just thought they have different characteristics.