I use a pair of diesel bladerunner mowers and I am extremly happy with them! Yesterday a dealer wanted me to try out a zd28 kubota rated a 28hp. It is a pretty nice machine I do not like all the gadgets and it is similar to the zd21 but overall pretty nice. My question is were are they getting this hp rating because it bogged a lot in the heavy leaves? Now I am not only saying that it was underpowered but I have also test drove exmark and encore with the 27hp briggs diesel and they to were very underpowered especially with a 72" deck. Now on the other side I have also test drove a dixie chopper with the 23.8hp engine that they call 26hp and it seemed decent or atleast it had more power than the briggs. I have a 27hp and a 32hp bladerunner and they both have lots of reserve power. So is the hp rating a sticker or do manufactures of these engines just rate them diffrently when they market them to the mower manufacture, or is it the mower manufacture that rates the power such as I beleve is the case for dixie? Or is there just that much diffrence in the diffrent brands of diesel engines? I know it's a lot to digest but just currious as to what gives! Maybe some of the manufactures of these mowers could explain the ratings.