I have an MTD Yard Machine. I have changed the battery,spark plug and the air filter--
The mower still won't start. I had the battery rechecked and the technician said the battery was fine. Changed the plug and started mower--it was idling really rough.
Restarted and it died and wouldn't start after that.

How long did the mower sit without use? Always start each season with freshly bought fuel. If this is left over fuel I would dump the tank and empty the carb bowl, start fresh.

Thank you it started wrong spark plug.