I have a 1989 50hp 2cyl on a Tracker 17' deep V. At full throtle I dip into the red line,(5500 on the tach), to 5800 rpms. I have a 11.5 X19 prop (which I damaged today on a rock. I would like to know if I should make a pitch adjustment when I buy a new prop? ANY Advice greatly appriciared...