anyone upgrade their 9.9 to 15hp by buying a new carb? I have read about it, but have a few questions. Is it worthwhile? Is there a substantial increase in power? Would the motor still be as reliable? Any recommendations would be appreciated. I presently have a 1999 Johnson 9.9. My 16' smokercraft goes 15mph when i am by myself. Wondering what I could expect if I upgraded.