So the reason the Kawasaki 6hp can be used successfully on the 30 is the same reason as it was enough on the 26. It is not direct drive like a 21 is. They use spindles and on top of that spindle is a very well calculated pulley that allows the engine to stay in the peak operating range. Now wet thick tall grass will slow it down but it also does so with a 21, 36, 52 or 72. In those conditions you need to slow down like any other mower. The kawasaki 6hp is a great mower and has had test that range from the low 6hp up to almost 8 I believe, need to find that site again. The good thing about Kawi motors is they guarantee the hp they say it is to be the minimum that it will produce.
What ever I do I must do it right!