James Sweet wrote:
I had thought about powder coating the prop from my '69 Johnson V-115
but then I found it contains a rubber insert where it fits on the shaft
and I'm thinking the 400 degree curing bake would probably damage the
rubber. Is it possible to non-destructively remove that or is it bonded
in place?

It is pressed in only! A shop with a good sized arbor press could do it
for you, but I would replace the rubber if it is disassembled.

Are any of the off the shelf aerosol paints durable enough to hold up
reasonably on a prop?

No. Unless you move into a 2-part urethane or epoxy finish. Then it
still will wear off eventually.

I know some are readily dissolved by gas and oil.

The least of your worries. The action of the prop will take the paint
off faster than solvents it might encounter.

Rob