How do you change the oil on a Yard Machine 20 inch 3.5 HP push mower?
Unplug the spark plug wire first. Now lift it up. Under near the center you will see a sqaure shaped nut. It can be plastic or metal. Insert a 3/8 racthet end into and turn. I always use an extension. Take the nut out and the oil will come out. Let it completely drain. I usually let it set for ten minutes or so. You want to let any sludgy build up come out. Then when that is done reinsert the nut. Do not over tighten it or it might break or strip out. The lower the mower and open the oil check hole. Fill with oil until it reaches the top just under the threads or whatever method this mower uses. Thats it it now changed. Good luck.
