I have a 1990 18 with a 2001 Mercury 90 2 Stroke. Pushes the boat 34mph with a 15 pitch prop at 6000rpm. I cruise at 4000rpm. She is great on fuel. It is a little underpowered when I have 4 people on the boat, however, it still will run 32mph. Getting ready to put a jackplate and hydraulic...