1. Park the mower on a flat, level surface.
2. Turn off the engine and allow it to cool down.
3. Disconnect the spark plug wire to prevent the engine from starting accidentally.
4. Tip the mower on its side so the oil drain hole is facing down.
5. Locate the oil drain plug. It is usually located on the bottom of the oil pan, near the front of the mower.
6. Place an oil drain pan under the oil drain plug to catch the oil.
7. Use a wrench to loosen the oil drain plug and allow the oil to drain out.
8. Once the oil has drained completely, replace the oil drain plug and tighten it securely.
9. Dispose of the old oil properly by taking it to a recycling center.
10. Refill the mower with the recommended type and amount of oil.
11. Check the oil level and add more oil if necessary.
12. Reconnect the spark plug wire and start the mower.
