Can someone tell me a ratio between pitch and prop diameter? Here the deal.... I have an '89 SeaRay 200 with a 4.3LX Mercruiser Alpha One. The boat weights 2300lbs. It has an 13.75 diameter x 21 pitch prop. I tore the motor coupler out running 5500 RPM at 45mph. Since then I've found out that engine needs to operate between 4200 and 4600 RPM. I found a 14.5 x 21 prop in hopes that it will cut down the RPM's but have not tried it out yet. Any help would be apreciated!
