Originally Posted by MustRib
Maybe I ought to get the 25hp Yam and put the hood from the 20hp on top!
Or can you get the cheaper 20HP and uprate it by replacing carbs?
I have the 20HP myself so would be interested to know.
I think you will notice the difference from 15-20HP though (I have no direct comparison as not tried 15 HP on my boat). Its possibly misleading to think of this as adding just 5 extra HP - but rather think of adding 33% extra power.
I don't know how HP varies with throttle on the yam but if it is linear (i.e. 3/4 throttle is 15 HP on the 20HP model) then you WILL notice the difference. On my boat 3/4 to full throttle is at least 5 knots difference in the flat.