1972 Evinrude 9.5 HP, Model 9222:<br /><br />I want to get a spare prop. The prop on the motor now, the "standard" prop listed in the parts list, is an 8-1/8x8.<br /><br />I can get an 8-1/8x8, an 8-1/2x8, an 8-1/4x8-1/2, an 8-1/2x8-1/2, or maybe even some other sizes in this range.<br /><br />I realize the objective is to select a prop size that allows correct RPMs at WOT for the boat size and weight but I don't have any way to check that.<br /><br />Practically, is there much difference in the performance of the above listed prop sizes on the same motor/boat combination?<br /><br />Thanks,