Place a drip pan or other container on the side of the mower with the filler. Carefully tilt the mower so oil drains out and into the pan. Discard the spent oil into a proper disposal vessel. Now slowly pour fresh oil into the mower. For the specific type of oil you need check your instruction manual. Make sure to add only as much as your particular model requires. Remember to let the mower sit undisturbed for a few minutes so the oil settles properly inside the engine.
The Sun Joe MJ104E has more than 1250 five-star reviews on Amazon. Buyer Jim has had his Mow Joe for more than a year and left it in the weather and abused it otherwise. He is happy with how it has performed. He cautions against buying the 16-gauge extension cord recommended by Amazon. Instead choose 12 gauge for 100 feet or more and 14 gauge for under 100 feet.
The Greenworks 20-inch 12 Amp Corded Lawn Mower has a lot of features that can make your mowing experience enjoyable. Since it is corded you dont need to stop to recharge a battery or gas up. It is a three-in-one that has mulching side discharge and rear bagging capabilities. There are seven cutting height positions ranging from 1.5 to 3.75 inches and you can adjust the height with a single lever. Plus the 10-inch rear wheels 7-inch front wheels and 56-pound size make it easy to push around the yard.