Engine mountings alignment

[Fender151]

I have  replaced the lock nuts on my engine mounting brackets,  in doing so, I can see that the adjuster nuts are not aligned across the two front mounts, the two at the rear are aligned, and at different settings to both fronts mounts.

I am aware there is a vibration through the boat when in neutral, and I want to see if this is due to the engine alignment.

 Can anybody advise if there is a process to follow to correctly align the mounts.

Thanks,

 

PS, take it as read that I had to replace the nuts.

[mross]

Depending on the flexible between the gearbox output flange and the flange on the propeller shaft, you need to get the two flanges parallel and the shafts at the same height.  The two front mounts should be at the same height.  The two rear mounts should be at the same height but this will be different from the front mounts if the propeller shaft is inclined.  Some flexibles are more tolerant of misalignment.  Do you have the installation instructions for the flexible?  If the two flanges are the same diameter it's much easier

Edited March 21, 2017 by mross
corrected in the case of flanges of differing diameters

[nicknorman]

But surely bad alignment doesn't affect vibration in neutral, only when in gear?

[mross]

I was thinking that the engine is not well supported because one front mount is carrying more weight than the other.  But it's a good point!

Edited March 21, 2017 by mross

[WotEver]

Just now, nicknorman said:

But surely bad alignment doesn't affect vibration in neutral, only when in gear?

Agreed.

Failed mounts can give rise to vibration in neutral. I was amazed at how much smoother WotEver was when I replaced all 4 mounts. 

[dor]

The bane of engine alignment is getting it correct across the diagonals.  If this isn't right, then you can (and do!) get vibration in neutral.