The Johnson/Evinrude's are good motors. Should be easy to get parts for.
You might have trouble getting a shop to work on a older motors, but if you can do it yourself that wouldn't be a problem.
It (85 HP) would have enough power to pull skier or tubers, and get about mid 40's for top speed.
If your motor has tilt & trim that would be a huge plus.
Do you know the year built ? If not post the serial number ...
If you like to work on stuff .. old motor is cool.
If you want something reliable and don't like messing with stuff, you might want something newer or rebuilt / running.