Based on the model number you provided your mower has a Briggs and Stratton engine.
White smokes indicates there is too much oil in the engine. As per your
,page 2, the engine you have on your mower takes 18 oz. of 30 weight oil.
When you check the oil, pull the dipstick out and wipe it off. Reinsert the dipstick and twist it to lock. Then check the oil, it should not be over the "FULL" mark, if it is drain some oil to bring it down. Always check your oil before starting the engine and keep the oil level at the "FULL" mark. Too little oil could damage the engine, for example it could throw a rod, or lock up. Too much oil can blow out oil seals and make the engine smoke and other problems as well.
I hope this helps.
If I can be of further assistance please feel free to submit any questions you have along with the specifics.
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