Re: Prop Questions for my 1999 175hp Evinrude
You asked "how is the boat used?" I spend a lot of time fishing, traveling to and from and we do some leisure cruising, no skiing or tubing. Most of the time my cruise range is 3600 to 4200 rpm. The boat runs at about 28 to 29 mph at the 4200 rpm. I don't know the make of either aluminum prop (I have 2 props) for the 175 hp Evinrude, but I can tell you I suspect the one I'm running right now has most likely been reworked based on the letters/numbers that have been stamped on the prop itself. Some are actually "x"ed out. The only visible difference I see between the two is on the edges of the blades; one is almost twice as thick as the other. They are the same diameter and pitch, and no, I don’t know if they are cupped or not. If we don't go out first thing Sunday morning, I will check the props over for manufacturer’s name. The reason behind getting a stainless prop is that my other boat has a stainless prop (1979 70hp Evinrude on 1963 Starcraft Holiday (18' 4")). It runs about 2mph (33 mph at just under 5000 rpm) over the aluminum prop that I purchased as a backup. I couldn't begin to tell you the difference between diameter and pitch right now without checking, but I think they may have an inch difference in pitch between them. My thoughts were that if a stainless prop helped my 70 hp run a little better, I figured the same would be true for the 175 hp motor. As for my spec for w.o.t. of 5300 to 5800 rpm, that came directly from the owner’s manual. I was thinking that the midpoint of 5500 rpm would be better and would allow the 175 hp to run a little easier, but the 250 rpm difference may not really be that noticeable.
