They are the same as stated already in 1998 they upped the displacement so the later motors make more torque and can get the impeller spinning a little faster. So if you can go for a later 59ci merc. I have 1993 60/40 tiller short shaft mariner same as mercury just different paint currently it has been a good motor no real complaints. But the evinrude/johnson 3 cylinder engines just run a little faster with the jet, I ended up hunting down a deal on a 70hp evinrude tiller with a jet that I'm going to swap once goose/duck season is over here. I really don't have any reason for switching other than that I am partial to omc's. Once I swap I will be selling the mariner which I have the prop lower for, and extra AG outboard jet as well.