I'm trying to help 2 of my friends prop their new boats correctly. One has a 2006 115 4 stroke Suzuki on a 19ft. bay boat with a 19 pitch prop & is reaching 6100 RPM's at W.O.T. (39 mph). The other has a 2005 115 4 stroke Yamaha on a 18ft Bay Boat with a 17 pitch prop & is reaching 6000 RPM's (43 mph). I feel that both props are undersized & they could move up 2 inches in pitch & get more mph with less rpm's & better fuel efficiency. Any thoughts?
