I really appreciate the detailed explainations and the reference materials.
The link in your reply gives me some confidence that I should be able to get it done with my own skills & tools. The link also gives some good diagnosis tricks to test the results of my efforts. I was also encouraged to know that my set up (prop shaft diameter of 1") is less sensitive than larger shafts.
Just to fill you in on a few things that came up in your response. The boat is older - 1972 NorthStar, repowered with a Universal M4-30 in 1993. The mounts were replaced in '93, so I'll be looking at their condition.
The shaft and coupling were replaced in 1998 due to a miscue by a surveyor that caused the shaft to bend (he tried backing out of the sling before the sling was out of the way on a short haul after a sea-trial - yikes!). So those parts are now solid and true. I also have a dripless stuffing box installed, replacing the hard-to-reach stuffing box. The cutlass bearing looks good and is just 2 seasons old.
Thanks, again for the very informative and helpful replies.