1. Park the lawnmower on a flat, level surface. Engage the parking brake, and turn off the engine. Allow the mower to cool down if it has been running.
2. Locate the oil drain plug. Consult the lawnmower manual if necessary. The oil drain plug is usually located on the bottom of the oil sump.
3. Place an oil pan under the drain plug to catch the drained oil. Make sure the pan is large enough to hold the entire volume of oil in the sump.
4. Use a wrench to loosen the oil drain plug. Be careful not to drop the plug into the oil pan.
5. Allow the oil to drain completely from the sump. This may take several minutes.
6. Replace the oil drain plug. Tighten the plug securely using a wrench.
7. Locate the oil fill cap. Consult the lawnmower manual if necessary. The oil fill cap is usually located on the top of the engine.
8. Remove the oil fill cap.
9. Use a funnel to add the correct amount of oil to the engine. Consult the lawnmower manual for the recommended oil type and capacity.
10. Replace the oil fill cap. Tighten the cap securely by hand.
11. Start the lawnmower. Let it run for a few minutes to circulate the new oil.
12. Check the oil level. The oil level should be between the "full" and "add" marks on the oil dipstick.
If the oil level is too high, drain some oil from the sump. If the oil level is too low, add some oil.
