Outdoor Power Equipment and Small Engines - B&S 15.5 ohv problems - sears rider mower

i was mowing my grandpa's lawn today and all of a sudden blueish smoke started billowing out of the muffler. he had added oil not long before i started. we checked the oil level and it was fine so i continued to use the tractor. i had noticed a significant power loss as blue smoke kept creeping out of the muffler - sometimes pouring out. i kept riding it out to see if the oil burning would stop but eventually the engine stopped :confused: so im looking for advice as to what it might have been. im taking it apart tomorrow but i dont think it was the head gasket because the smoke was intermittant. someone had mentioned the o-ring on the oil dipper and that seemed more appealing to me haha. but any advice would be nice as far as typical causes of this type of problem... just so i know where to look... thanks alot in advance -Derek

Sounds to me like the oil is too full, has gas in the oil, or the head gasket is blown.