Riding lawn mowers require a bit more maintenance than the push variety. As high-performance machines, they use a higher-quality oi, and require frequent oil-filter and oil replacements. The oil typically requires changing every 50 hours of running time. When the oil is changed, the filter requires replacement as well. Make sure you check your mower's maintenance manual for specifics on which oil and filter should be used with your model.
Warm the mower engine for 5 minutes to get the oil running freely throughout the engine.
Turn off the engine, remove the oil-filter cap, and locate the oil tank's drain plug, which is under the oil crankcase.
Position the oil pan underneath the drain plug, and remove the plug. Allow the oil to drain completely. Your mower might require a drain hose and siphon to drain the oil completely. If so, slide the drain hose over the drain valve, point the end into the drain pan, turn the hose slight counterclockwise, grip tightly, and pull to release the oil.
Replace the oil plug and cap once the oil is finished draining.
Remove the oil filter by attaching the filter wrench around the filter, and turn it counterclockwise to unlock the filter. Remove the filter by hand, and replace it with a new one. Run a small amount of oil over the new filter's seal on the bottom to create an airtight seal.
Fill the crankcase with oil, and start the mower to get the running through the system.