2003 90 hp 4-stroke on 1976 Mako

[hbillhead]

Need to know if any one knows what Prop I need to run on this boat. I have a 14x18 Prop now and its to small. At 6000 RPMs I am only running about 28 miles per hours and the boat start to porpus. I have been told that I need to go to a 14 x 20 or a 14 x 22 prop to slow down the RPMs and get the top end and speed on this boat. Please Help.

[boats.net]

Propellers are trial and error, however rule of thumb is for every 1 pitch up you will loose about 200-300 rpm's/gain top end and visa-versa for 1 pitch down.

[hbillhead]

2003 90 hp 4-stroke, 1976 17 ft Mako

Thanks for your advice , hbillhead