Re: 3 blade or 4 blade ?
In the most basic comparison with all other things being equal, a 4 blade should produce more bottom end punch than a 3 blade and the 3 blade should produce a bit more speed. The 3 blade has less drag and the 4 blade has more surface area to grab the water. On a motor that size and the application that you're using it, I don't think you really need to worry about either. Buy the cheaper one and buy something else you can enjoy with the extra money.