I had a 1648 and put a tiller 1998 Suzuki 25hp on it. Loaded it would go 26 mph gps, and by myself it would go 30mph. Those older Suzuki 3cylinders were fast. If the new 25 and 30 hp motors are equal priced go with the 30. If there is a big price difference I would be happy with the 25, not sure...