Gordon, question on Yanmar rear engine mount...

[Ernie Rodriguez]

I have noticed that the rear engine mounts for my Yanmar 3GMD (1982 Hunter 36) are mounted on a level surface while the front engine mounts are at an angle. This results in less clearance between the two metal parts of the mount at the rear of the mount compared to the front of the mount. Is there some advantage for installing the mount this way, or would it be better to have the rear mounts at the same angle as the front mounts? Or maybe the front mounts should also be mounted on a level surface, but higher than the rear ones?Would appreciate your comments on this.

 

[Gordon Torresen]

Engine mounts

The Yanmar engine mounts have always been attached to the engine in the same plane. The engine beds built into the boat should be in one plane, parallel to the prop shaft and level athwartship. If I recall correctly, some of the earlier Hunters had angles bolted to the engine beds upon which the engine mounts sat. If you have this configuration, maybe one of the angles has moved. Anyway, the mounts work best if installed as designed.

 

[Ernie Rodriguez]

Thank you, Gordon....

you have confirmed what I suspected. In my case, there are angles added to the engine bed for the front mounts, but the rear mounts do not have any angles, so the front and rear mounts are not on the same plane like you mentioned they should be. This helps to explain the knocking noise I hear when the engine is vibrating at low engine speeds of around 850 rpm. The top and bottom pieces of the mounts are hitting each other because of the small clearance.