1992 Mercruiser 4.3L D612478
Alpha one gen 2 OD576546
Removed engine, to replace spun coupler. Upon removal noticed the engine flywheel cover housing was setting flat down on the transom plate. No double wound lock washer or fiber washer. Bought a coupler and yoke from local marina and inquired about the other components. They said by their parts diagram it should have the double wound lock washer and the fiber washer but the fiber washer wasn't real important, just a cushion, wouldn't affect ability to align engine. In my research I see there is a new style rear mount with serrations on the bottom which does not require the double wound washer. My rear mounts have a smooth bottom edge.Having difficulty getting alignment exactly perfect, it's very close. Alignment tool goes in smooth and easy to about the last 1/2 -3/4 inch, and I can't seem to get it any better. Any one have experience with this(yes or no on double wound washers)? Should I still be able to get alignment correct? Side note: this boat has had "repair" done to right side stringer/motor mount area.

put the alignment tool in all the way and smack it side to side with a rubber hammer to get it aligned with the gimble bearing.do this with the transom bolts loose

I have knocked the alignment tool left right up down to center the gimbal bearing. Which transom bolts are you referring to? Rear engine mounts?

yes you need to leave the rear bolts loose, the long ones that go through the bell housing, this works for me

Then put the drive on and tighten

Never been told that before. Thanks for your help.
My concern was that the stringer repair was causing my problems, but did not know how to diagnose it.(maybe I just suck at engine alignment) Just know alignment tool is not as smooth and easy on this boat as it is on mine.

Di you install the new style Bushings,,or use your old ones.
I just pulled a 2006 525 efi. that had new style bushings,,and,,it had the spiral wound lockwasher under it,, which the instructions say to leave out,, alignment was perfect with this combination.

Adjusting mounts need to be even amount of turns up or down IF (big if) they were level with the rear mounts to begin with.

If unsure, attach a hoist to the thermostat housing, rear mounts just snug. Lift the front of the motor just enough so there is a gap under both adjusting nuts. Now turn the nuts up so they just touch with even force on the underside of the motor mounts. Once done lower motor and you can now adjust up/down evenly on both sides

Could also get a tool 91-863372 which will show which way the mounts need to move

253 : I did not replace the bushings. They had the old style smooth bottom edge. I installed the double wound washer which was missing when I removed the engine.
All Dodge: the mounts looked very even, but I followed your directions and they were off slightly. Evened them up.
F-2 after getting alignment close as I could I followed your tip and that seemed to put it where it needed to be. Smooth enough going in and out I was confident in alignment.
Last question, I hope, when installing a coupler do you guys always check run out or just torque it down evenly and go with it.
Thanks

the key to coupler alignment is you have to use the shouldered bolts like the stock Merc ones, and I put blue lock tight on the threads, torque it down and run it

The forward mounts do not have to be even. The engine needs to be square and aligned to the transom assembly. If the bracket the adjustable mount is bolted to is not even to the other side, one mount will be lower or higher than the other.