Corrosion resistance !
Most racing motors only leave the lower unit bare. Well, actually they are bare then clearcoted. I dont see a huge issue with it. Unless its an old alka-seltzer suzuki lol (someone might appreciate that joke).
Yeah, to a point. But who likes dull aluminum? Should I rephrase by saying that paint looks better than dull aluminum?Does it protect from corrosion?
And isn't aluminum oxide basically a tough inert substance?
So aluminum basically is self sealing?
Brett, thanks for the reply. It made sense to me, but it's good to here explanations! ;D
Just to add more confusion to the conversation............ All aluminum is not created equal. I've seen jon boats, dock ladders, chairs, and a host of different aluminum items that lightly oxidize and stay that same dull gray that seems to last forever without further deterioration.
On the other hand, I've seen hardware that "looks" like aluminum form a thick white crust and eventually crack like rusted steel. We referred to a lot of this using the general term "pot metal" in the past as they were aluminum alloy castings - not the extruded/machined aluminum we see in other applications. I'm sure the alloy contains other elements that are not as corrosion resistant - perhaps more magnesium, less aluminum. With some older outboards I've seen the same thick oxidation be the culprit for popping off the paint. I'm not sure what alloy of aluminum is used for outboards, perhaps there are several depending on mfg. and year of build.
I would have great concern over not painting an outboard in the long term.