I had a 70hp on a 15' Whaler CC. It was the perfect size for
that boat, as long as I had three or less people aboard. Once
I got to four or more, the boat took much longer to get on
plane, and the engine seemed to strain.

On a 17' CC, I'd want a 90hp minimum.

I assume that we can get a 17-ft boat on plane quite well with a 90hp
motor as long as we only have one or two persons on board. This also
means that 90HP will not be enough for a 17-ft boat if I have four
persons on board. Because of the fact that I like to have three or more
persons on the boat, this means 90HP is not enough then, and I will
have a problem getting the boat on plane. Sound like I will need a
115HP motor, and stop thinking about 75HP, 90HP motors.

OK, 115HP will be IT!!

Thanks for sharing your experience. This surely helps me to narrow down
the selection very quickly.

Jay Chan