Tom beat me to it but I spent so time on this so
this is what I can offer.
The cooling system is a pump.
A piston operates from an eccentric on the prop
shaft gear. You’ll find some wear on the bottom
of the piston but unless its extensive you should
be ready to go.
You’ll probably find some pitting on the eccentric.
Someone once told me the pits carry grease
providing lubrication. As most don’t have the
equipment to repair this we just run them as is.
It works for me. If the pitting is really severe
check the bottom of the piston from time to time.
You don’t want to wear a hole in it. You can solder
on a piece of copper or brass as a repair.
Most of us can handle that.
There are 2 check valves that should be looked at
to be sure they are not stuck or dirty. You can just
stick the pump in some water and work the piston
to see if it pumps. If you need to remove the caps
I suggest you clamp them in a vice and twist the
pump to remove them. They are often very tight
and the soft brass is torn up easily.
Tubs.
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.