Originally Posted by
John Grinder
I recently bought a 2005 Classic 18. Mercruiser 5.7L 300hp, Alpha One stern drive. At 5000 rpm I am going 60mph. At full throttle I am approaching 5400 and 65mph. I do not want to run over the red line of 5200, but I would like to be able to operate at full throttle with maximum speed.
the prop is a 3 blade stainless. The only markings on the prop are the numbers 9170 and 21. There are no manufacturer markings I can locate. I don't want to invest in a new prop of higher pitch without some confidence with what I am doing. Any advice you could offer would be appreciated.
For a deep drive like yours I would borrow and try a Mercury Rev4. It's a through hub 4 blade which you can get with PVS vents which I would suggest as an option.
1972 16 OB - C16B-63 - "Surface Tension" Resto Project
1974 16 OB - DMR16106017-B - "The Mule"