If this has the MTD made in China engine something else you may want to check is the air gap clearance on the ignition to flywheel. The gap is .008-.016 and you may have to adjust it a .001 at a time until it will start with the electric start. Had one a few years ago that would start manually but wouldn't start with the electric unless the air gap was .012. Wouldn't work at .011 or .013. This was after trying a new carb, ignition module and spark plug.