True North wrote:
If you bought a new boat in the size range he's talking about, the dealer
would try to sell you an outboard in the 100 hp range.
My 25 Johnson was fine on the 14.5 foot Yukon open aluminum boat and my
current 16.5 foot Fish and Ski runs well with the 60 hp Big Foot although
I could have maxed out at a 75 hp.

You probably should not have a Big Foot on a 16.5 boat.