I redid my tohatsu head recently. Stripped as much off it as possible (throttle links, carbs, coils, cdi unit etc) used brake cleaner to remove salt and grease then removed all loose paint with a flat head screw driver and rag.
I used black hamerite spray can then cleaned all the parts off before refitting. Looked good as new and has held up perfect!
I also re sprayed the gearbox using a some outboard marine paint from eBay. Colour matched pretty well! No primer needed just removed the water intake guards.
Always wax my engine to help the salt water bead off too.