In my Husqvarna riding lawn mower with the 21hp Kohler Courage engine. First of all, if you see a leftover mower with a Kohler courage engine in it, don't buy it. It's a lousy engine. It's severely critcized in the lawn mower repair videos. Mine had 64.5 hrs of operation when the rod started knocking. I installed a new engine short block and it's back to cutting the grass. I know a lot more about lawn mower engines now that I didn't really care to learn but I was too cheap to throw it away and buy a new mower with a crappy engine. May as well just buy a new crappy engine.