OMC sounds and tune up

Hey it's boating season again!

I have been reading about the OMC's shifting and posting some myself. I have a '86 4.3L OMC Cobra, that I have some concerns about. What I would like to know now is, should it make some sounds shifting from N to F or N to R when on muffs? I am assuming this is ok, because it is not on load. I don't recall it making any noises while it is in the water, though it has been a while now since it has been swimming. On a slightly different note, what can anyone tell me about compression testing this motor? I just bought a compression test set and timing light. I am getting myself ready to do a total tune up. I have both OEM service manual and a Seloc, but info from people who have done it is great.

Thanks for helping me get my boat out and running smooth!

Re: OMC sounds and tune up

The clunk going into gear on the muffs is normal.
In the water you don't hear it as much. Use a brisk shift into gear.Don't try to ease it in.