I have a X738, 2 years old with 60 hrs, which has pushed blue smoke for short period of time at start up. Today it blew blue smoke while mowing. It lasts a couple seconds, occurs about every 5 minutes and blows different amounts of smoke each time. One time it is a puff, next time you think you’re in a ‘76 Gremlin. I looked for a crankcase breather thinking it may be the cause but can’t locate it. Engine oil looks good, no fuel in it. Air filter looks good. The engine doesn’t miss a beat while happening. After an hour of this it stopped doing it. ???