Keeping your lawnmower in top condition is crucial in order to keep it working properly despite the abuse it takes during the mowing season. One area of maintenance people often neglect is changing the oil. Many people check the oil but feel that if there is a sufficient amount of oil in the engine it is good enough. Changing the oil in your mower should be done after five hours of use for a new mower and then every 25 hours of use.
Lay your mower on its side.
Find a square bolt head protruding from under the mower engine. Adjust the crescent wrench to the size of the bolt. Turn the bolt counter-clockwise until the bolt comes out and oil begins to drain out.
Grab the square-headed bolt and quickly lay the mower over the oil capture pan. Wait about a minute to allow all the old oil to drain out of the engine.
Prop the mower back on its side and tighten the square-headed bolt back into the oil pan hole on the base of the mower engine.
Return the mower to its upright position. Unscrew the oil dipstick. Read your owner's manual for the proper amount of oil to add. If you no longer have your manual then slowly add the oil to the engine by pouring it through the funnel and into the oil dipstick hole. It usually take 20 ounces to fill a small mower engine, so pour in some oil and check the oil level with the oil dipstick occasionally until the oil is to the FULL line on the oil dipstick. Screw the oil dipstick back in once you have enough oil in the mower engine.