[C320-list] Transmission Reduction Ratio for Perkins M30

[Jeff Smith]

Can anyone tell me how to determine the transmission reduction ratio for a Perkins M30? Watching the conversion about the right prop, I emailed PYI to find out what pitch I should set for my prop and to confirm my settings. They said it is a function of prop diameter and the reduction ratio. My manual says Perkins M30 has either 2.05:1 or 2.73:1. I believe I have the latter but I want to confirm before I haul the boat to change the prop pitch. The Max-Prop Classic has two settings and I now think I missed each setting by one tooth, causing my prop to have a 14 degree pitch instead of the recommended 24 degree pitch.

Thanks,
Jeff
’94, #121