Mower troubles

This guy wouldn't work at all on Saturday. I wasted a few hours tinkering around with it. I changed the air filter, spark plug, and checked the oil several times. The damned thing just didn't want to work. I took it back to Wal-Mart on Sunday. Exchanged for another new one. I had only just bought the last one. At the beginning of August when we moved into ths house! Oh well. The grass is mowed as of now.