"Jim Newell" wrote in message
...
Why are smaller outboard motors water-cooled?



I am thinking 5 - 9 HP engines.



I understand why inboard, inboard/outboard, and larger outboards are
water-cooled; but why are smaller outboard engines water-cooled as well?



Wouldn't air-cooling be simpler?


I think existing design is the biggest reason. Outboard motor design hasn't
(at it's core) changed a whole lot in 70 or 80 years. The 2 glaring things
which dictated water cooling that pop out to me are;

1) weight. Air cooling requires fins. Until (relatively) recently, those
fins would have been a weight restriction.

2) noise. The added covering (while lower weight than fins) reduces noise.

I guess a 3rd thing is the instant access to all that cool water is another
influence. No issues with airflow, just scoop some cool water up and run it
down over the parts that house moving parts.

Ed