Re: are there that few 89 50's around
Lots of those engines around yet.
Maybe not in Florida, cause the saltwater ate them up.
Many parts are still available fro Mercury.
Most that aren't available from Merc, are available from aftermarket suppliers.
Best manual to get is either a factory manual, or the Clymer Force repair manual.
Best parts sources:
iboats
Merc dealer
mercruiserparts.com
maxrules.com
outboardparts.com
What do you need to know?
What parts do you need?