How do you change oil in a Craftsman 625 series lawnmower?

The oil drain plug for the Craftsman 625 series lawnmower is located on the bottom of the mower, just above the blade. Tip the mower back. The plug is round and threaded with a square head. Using the square head of a ratchet extension, twist the plug counterclockwise and remove. The oil will start draining. Once it has drained, replace the plug and tighten clockwise until snug. Replace with new lawnmower oil or SAE-30 weight oil.