Started my third cut with my new X One when the engine started running rough and heavy smoke from exhaust. Inspected the engine and checked oil, all was fine. Restarted and engine would not increase on rpm past idle, which was rough and exhaust smoke. Engine started making loud noise and spitting small metal parts from exhaust. I assumed broken rings and dealer will replace engine. Dealer recommended running 15 hours on break-in oil, but that sounds like a bit too long and suspect that may have been the problem. With the new engine I plan to run break-in oil at half throttle for about 1-2 hours and changing to regular oil. Will welcome any comments and debate.