Demo'd the Super Z again today and saw a sizeable amount of blue smoke at startup from the motor. It cleared fairly quickly but I hadn't noticed it before nor have I noticed it from other 27 HP Kohlers I've demo'd. Was it a fluke? The mower is a demo unit with 50 hours on it. Is this normal for 27 hp Kohler Command Pro's to puff and occasional blue smoke at startup? Then, after the demo when I shut it off, the motor wanted to sort of keep running, then it backfired and quit. The dealer blamed it on the lean settings in the carb - again, is this normal?