I recently purchased a 1989 16'6 Crestliner with a same year 85 hp Suzuki. The origanl prop was mangled but would trim out at 4500 rpm. A new 13x 17 Hustler prop trims out at 4500 rpm as well. New plugs made no difference. Any suggestions on where to start fiddling around. Will probably use Sea foam to clean the carbs.