Most Kohlers need to be shut down at half throttle or above to prevent backfires. Says right in the owners manual. I think the big reason manufacturers do things like this is Kawasaki will keep giving discounts. The more engines you buy, the less they cost. Kohler has like a few set numbers. For example you get this price for 100, another for 1000 and another for 5000. But after you are over the highest there is no more discount.