Twin I/O's engine alignment question
 

Completing annual maintenance on my twin. Alignment on the port motor was off a smidge. Alignment bar went in with some force, and didn't bottom nice. Grease indication was on the bottom. Ended up raising that motor in the front approximately 1/8" or more. Alignment is pretty good now. Bottoms out nice, and shows grease marks about 3/4 around it. I did not crank motor and check at every 90 degrees. Didn't know about that method until I had the drive back on.

Starboard motor was off on alignment as well. Same thing, bar went in with some grunt, and did not bottom out well. Showed grease indications on the top. When I went to adjust this motor mount, i noticed that the engine mount threads showing on the top of the lock nut was quite different than the port. Looked like almost 1" different. Is it abnormal to see twins with different locations on the front mount? Just due to irregularities between the stringer height or rear transom cut out? In general, it looks like the stbd engine is tipped down in the front, compared to the port.

I ended up lowering the front of the stbd engine even more, a little at a time and got to about 1/4" change and stopped. It made the alignment better, but not as great as i would like. I checked at 90 degree changes of the crank, and got varying results. I ended up coming back up about 1/16" or so. Bar goes in ok, and bottoms ok now. But curious when 90 rotations are different? I'm guessing the coupler must not be perfectly straight. Maybe the rubber takes a set?

Just second guessing what i'm doing actually helped anything.

Thanks for the insight.

No idea what your boat is or how old it is, but major changes to engine alignment don't tend to just happen on their own... The difference from port to starboard could be normal, hard to say, but one thing I would be thinking about is maybe drilling some test holes in the stringers and down low on the transom and checking for any signs of rot... The transom can become soft and compress and the stringers can do the same if there is any rot going on.. Hopefully thats not the case, but might be worth checking, unless of course you have composite stringers and transom... if you do decide to drill some test holes.. if all checks out okay, just fill the holes back in with thickened epoxy or some 5200 or something just to make sure water doesn't get in there.

Honestly, this is the first time i've checked this boat since owning it for 3 years. So i have no frame of reference in the past for alignment. Will going forward though......