Sorry all, I should have been more specific since there are apparently
not too many generic answers to the questions.

Okay, here are the two motors I was thinking about when I posed the
question.

++2008 Tohatsu/Nissan MFS 2.5 hp with 85cc motor.

++2008 Suzuki DF2.5 hp with 68cc motor.

The Tohatsu has a 25% greater displacement yet the Suzuki is rated the
same horsepower (2.5) as the Tohatsu.

-Jay