Small Engines (Lawn Mowers, etc.): craftsman lawn mower, craftsman lawn mower, cycle oil

Question
My sister has a craftsman 4 cycle mower and her grandson put 2 cycle oil in it. This was not a gas mix in the fuel tank but 2 cycle oil in the oil spot. It started smoking and they shut it off. Can she just drain the oil and replace it with 4 cycle or is there something else she should do?

Answer
Just drain the 2 cycle oil and refill with SAE-30 oil.  It will probably be alright but might smoke until all the two cycle oil is burned through the engine and muffler.  I would have a new spark plug on hand as the burning two cycle oil may cause the spark plug to foul.

Eric