Motor Mounts - Yanmar 4JH2E

[smokey73]

I think I need to replace the motor mounts and took some pictures. The diesel runs great and there does not seem to any significant vibration but looking at some other pictures of motor mounts installed on these engines it looks like mine have "sagged".

I appreciate any feedback on what I'm seeing. I know when I install new mounts I'll need the engine/shaft aligned and I'll do a bellows replacement on the PSS Shaft seal. I'm considering using the PYI motor mounts.

Any comments on how these mounts look compared to what you have would be appreciated.

 

[smokey73]

Well, looking at other threads these motor mounts may be fine other than the some rust on the metal. I don't have any vibration and the engine purs like a kitten. Its probably about time to replace the bellows on my PSS so when I plan to do that I'll replace the motor mounts and possibly even the cutlass bearing. Might even do the shaft strut too and then have the motor and shaft aligned. I have to check with the previous owner to see when the PSS bellows were replaced but I've had the boat since 2012 and haven't replaced it so we're looking at 5 years right there and I think the recommended interval is 6 years now for maintenance on the PSS shaft seal bellows.

 

[Sailor Sue]

My recollection is that you should be able to fit a 5/16th or 3/8th rod or drill bit between the top metal and the rubber.

 

[SG]

Do you have a vibration isolation connection between the drive shaft and the back of the transmission?

 

[smokey73]

No, there is no vibration isolation. I don't get any vibration though.

 

[SG]

If you are doing okay without vibration under way through the range of RPMs, I would not mess with it.

Some boats are designed to have soft motor mounts. Some are not. If you don't have any issues in a rough seaway while motoring, then I'd not worry. If, when the boat pitches, then things change, that would be different.

That's my advice.

 

[Benny17441]

If it ain't broke, don't fix it. Just keep an eye on them and wait for the first sign of trouble. Like SG suggests the proof would be to see how they behave in a rough seaway.

 

[Bill Roosa]

there is nothing wrong with those motor mounts. That "sagging" is actually a sign that they are relatively new. They are built so there is an angle between the motor and rails halfs to force the two together and compress the rubber. takes the stress off the rubber to metal adheasive

 

[Ken13559]

Given fore-mention of no vib, may I suggest you clean up the rust and paint it neat and call it quit. Buy a bottle of calamie lotion for your hands 'cos sometime "if it ain't broken don't fix it" can cause itchy hands and fingers. I know 'cos occasionally I'm inflicted with this itch