I just bought a brand new 1999 Merc 150 EFI that did not have a lower unit. I found a guy in Long Island that had 2 different lower units for this motor. One has a 1.87:1 and the other a 2:1 ratio. I have a 23' Mako and he suggested the 2:1, so I bought that one. Is the 2:1 the "standard" gear ratio, and if not, how will this effect the pitch of the prop I need ? I am definately going with the Alpha 4 aluminum 4 balde prop, but have no idea where to start as far as dia and pitch. Any suggestions would be great, remember Mako is a pretty heavy boat and this one is a 73'.
Koolwav, I would start somewhere around a 14x17 pitch for your rig.Diameter may vary slightly+-.The four blade is unnecessary in my view for a Mako boat(fishing).In general,a prop with less blades is usually more effecient than more.Fewer blades get a cleaner bite in the undisturbed water.You may get on plane faster w/a 4 blader though.Not sure which gear ratio is standard on your new Merc.