My old Grasshopper 721d had more power than my new 722d. My new unit has 70 hours on it now and i would like to turn the injection pump up. What I dont know is how much of a turn on the screw I can go. I am sure the pump on the 721 was turned up as I purchased it from a commercial firm and like I said, it has way more power. (The 721 is rated at 21 hp and the 722 is at 22) I had two dealers to chose from when I purchased my 722. THe one dealer, a smaller one who sold out of his farm barn said he could turn the pump up and get more HP out of it. He also wanted about $1900 more for the unit than the dealer I got it at. The Deere dealer though, doesnt seem to know or want to do it. It is a 3 cylinder Kubota engine.