Re: Why did OMC like the number 8?
I think the later 20hp is just an 18 with a slightly larger carb, isn't it? The carb on the 20 was 379032 and on the 18, it was 278402.
As far as the 28 goes, (1960's) that was basically a re-birth of the 1956 30, with an updated fiberglass cowling. Cubic inch displacement was still the same, but there was a different carb here too.
It looks as though, "de-tuning" was just a form of reducing the venturi size of the carburetion. Kinda like in the 9.9's and 15's of the later era.
