Lightweight, that 19 pitch sounds like it might not be enough. Do you have access to a friends 21P or 22P that you could try? I have a 2005 NX750 with a 115 Optimax, 5.5" manual CMC jack plate set at 4" below pad, prop is a laser 2 22P with cup added, and i'm hitting 50 mph GPS in the summer (53...