I own a 2004 Cub Cadet LT1018. It has a Briggs and Stratton 31Q777-0305 18.5 HP engine in it. Last week, it died. The last time I rode it, I thought it was running out of gas. When I shut it down, it let out a puff of smoke. I noticed that the engine was extraordinarily hot as well. Now, when I...