How new is you mower...if it has the small electrical device on the bottom of the carb check for gas in the oil and cylinders..it may have failed allowing the gas to flow back through the carb and into the engine ANOTHER FAILED EPA REQUIREMENT ..when this happens you motor will not turn over due to the cylinders being filled with gas..has happened to my Husky I added a fuel shut off and shut it off every time the motor is not running even for just a min or so....this is a DEFECT. you can replace the device but WILL FAIL AGAIN.......IF THIS IS THE CASE JUST CHANGE THE OIL AND FILTER AND TAKE THE PLUG OUT AND TURN THE ENGINE OVER TO BLOW OUT THE CYLINDER JUST REMEMBER TO COVER OR TAPE THE SPARKPLUG TIP TO AVOID. SPARKING.....I FORGOT. AND WHOA......LOL....WAS LUCKY......TAKE A LOOK AND GOOD LUCK.. How new is you mower...if it has the small electrical device on the bottom of the carb check for gas in the oil and cylinders..it may have failed allowing the gas to flow back through the carb and into the engine ANOTHER FAILED EPA REQUIREMENT ..when this happens you motor will not turn over due to the cylinders being filled with gas..has happened to my Husky I added a fuel shut off and shut it off every time the motor is not running even for just a min or so....this is a DEFECT. you can replace the device but WILL FAIL AGAIN.......IF THIS IS THE CASE JUST CHANGE THE OIL AND FILTER AND TAKE THE PLUG OUT AND TURN THE ENGINE OVER TO BLOW OUT THE CYLINDER JUST REMEMBER TO COVER OR TAPE THE SPARKPLUG TIP TO AVOID. SPARKING.....I FORGOT. AND WHOA......LOL....WAS LUCKY......TAKE A LOOK AND GOOD LUCK..