I believe that year takes the universal grip and
a reproduction grip is available as well as decals.
Lubriplate 105 or John Deere Corn Head Grease
should be used in the lower unit.
With that better than average gas tank I would
think if you offered that motor for sale, asking
$ 80.00, at a club swap meet it would go pretty quickly.
Here is a link to an earlier thread that may answer
some of your other questions.
Tubs.
https://www.aomci.org/forums/topic/1929-johnson-model-j-25-plug-wire/
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.