How to Change the Oil in a Yard Man Lawn Mower Model 12AV829C755

Start the lawnmower and let the engine to run for five minutes to allow the engine oil to warm up. Turn the engine off. Remove the spark plug wire from the spark plug. The spark plug is located on the front middle of the engine. Tilt the lawn mower upward, so that the air filter and spark plug are facing upward. Set a jack stand beneath the mower deck to stabilize the mower during this project.

Place newspapers and a drain pan beneath the deck and the engine. Insert a 3/8-inch-drive ratchet with a 3-inch extension onto the head of the drain plug on the bottom of the engine. Turn the drain plug counterclockwise to remove it. Allow the engine oil to drain for five to seven minutes. Install the oil drain plug and tighten it snug, using the ratchet and extension.

Remove the stand from beneath the mower deck, and lower the mower to its normal position. Remove the oil fill cap, which should have two prongs sticking up at the top. Use a flat-head screwdriver or pliers to loosen the cap if needed. Insert a funnel into the oil fill hole.

Add 1/2-quart of HD-30 motor oil to the fill hole to start. Check the oil level. Add oil in small amounts until the oil level shows full on the dipstick. Insert the oil fill cap and dipstick and tighten the cap snug by hand. Replace the spark plug wire back onto the plug. Wipe any spilled oil off of the mower deck and oil fill areas to avoid a potential fire hazard.