I have one in a Ferris 3100, it is carbureted. I learned of the valve problems, but also learned of the upgrades Kawasaki has done. I got both cylinder head assemblies and the cam shaft replaced for free.
I think it is a great engine. This engine on my 61 inch deck is real mowing machine. I mow a reforestation project, so I cut lengths much greater than any residential mower would ever see.