10-05-2021, 02:30 PM
This was my first year with a power boat, so my "know-it" bank balance is pretty low. I wanted to replace the aluminum prop on my Merc 50 (Tracker Classic XL boat) with a stainless one and all the online prop calculation sites told me I needed to go to a lower pitch due to altitude.
During my motor break-in and before I switched props, the OEM prop did seem to limit both RPMs and speed, but not by much. The replacement SS one gave an immediate boost to both - but that may also be due somewhat to the motor smoothing out as it gets used.
I also throttle back to 4000-4500 after getting on plane, btw. According to my Vessel View monitor, I burn only 2.5 to 3.0 gph at those settings and lose only about five mph from top speed versus 4.5 gph at top end. With Non-ethanol gas costing over $4/gal I consider it a worthy tradeoff.
During my motor break-in and before I switched props, the OEM prop did seem to limit both RPMs and speed, but not by much. The replacement SS one gave an immediate boost to both - but that may also be due somewhat to the motor smoothing out as it gets used.
I also throttle back to 4000-4500 after getting on plane, btw. According to my Vessel View monitor, I burn only 2.5 to 3.0 gph at those settings and lose only about five mph from top speed versus 4.5 gph at top end. With Non-ethanol gas costing over $4/gal I consider it a worthy tradeoff.