I have a simplicity mower (1998) with a 16hp vertical shaft vanguard v-twin engine (303777 1111-51). Yesterday, after running the mower with turbo bagger attachment (a little extra load on the engine), for about 20 minutes, I idled back the engine and it began belching large clouds of blue/white smoke. The engine appeared warmer than normal. Plenty of heat and vapors when I removed the oil dipstick to check the oil level. The oil level was at the lower edge of the "OK" level. I let the engine cool and changed the oil. (It was about time, 23 hours of use). I restarted the engine and it appeared fine. Smooth idle, normal power, etc. I finished the lawn w/o the bagger but can still make it blow some smoke when the engine is hot, if I quickly move the throttle from wide open to idle. Will not blow smoke if the transition from wide open to idle is made slowly. The engine has approx 270 hours of use with regular oil changes.
Any thoughts..?