Re: Need an idea of value... (Dad isn't too internet savvy)
The Johnson looks to be a run-of-the-mill TD-20, 5hp, built during the late 1940s. They made a LOT of them and many are still in circulation. Nice enough motors, generally not too hard to get them running if they're essentially healthy. With plenty to go around, prices tend to be quite reasonable, from a buyer's standpoint. Really nice ones don't tend to draw much more than $100-$150.
The Sea King looks to be a Chrysler-built 3.5hp, c. 1960s. Air-cooled, design dates back to 1950s West Bend "Shrimp" model. Simple motor, ran pretty well, but not very quiet - kinda buzzy. Not super sought after by collectors, but may have some service value by someone wanting a lightweight kicker for a small tinny. In "as is" shape, probably wouldn't draw much more than $75-$100, if that. If was shown to run, etc., maybe a bit more.