There were two dilapidated fiber washers (one each side) between the mounts on the inner transom plate and the mounts on the bell housing. How thick should the be? Can they be replaced with solid washer of same thickness?

Ayuh,..... Get some new ones from Merc, they ain't that expensive,.....

.160 thick

Well, I ordered new ones and they were .200 thick. Put it together and bar hit bottom of coupler. Had to lift front of engine and inch and bump bar around to get it close. So I made aluminum pieces at .160 and put front of engine back down where it had been and with a few minor adjustments had it lined up.
Thanks for the assistance.

Should search your transom assembly sn...there are usually springs or washers inside the fiber washers. ours did Atleast and it depends on the SN.

I found that out yesterday about there being different versions. I have a '90 or '91 Bravo outdrive and transom assembly. Whomever swapped that left the Alpha coupler and engine mount assembly in place. I switched to the Bravo coupler and engine mount. The engine mount I have is the newer style that does away with the springs.