Hey guys, been busy at work and got home late last night. Went on bike ride and got home to a call from in law. The JD STX we gave him, blew up?? :dunno: Was told it put out a big flame out pipe and died. I thought the dork ran it out of oil!:bag: Got there and tried to start it, runs,but makes a real loud knock type sound, not rod. The engine is running ok otherwise?? We towed it home with big Toro. I mowed for him first to try our machine out. I wonder what happened? You guys think it might be the valve seat (s) ? We will check other things first, loose bolts, etc. The flame thing makes me think something in head. Even when cranking it, can feel the clunk in frame?? Any ideas??