48" WB Encore mower, kawasaki 420v with hydrostatic drive. Starts right up, idles fine but will die after some use. Feels like it loads when using the drive controls and will die unless i choke it. I can shut it off and wait a few min and it will start right up again. I have throughly cleaned the carb and blown it out with the same results. I love the mower and have not had any problems since buying it some 4or5 years ago. When the issue begins I feel a slight shudder in the hydro controls. When the change in rpms begins I have disengaged the drive and the blades but the engine still dies. I can only keep it running by choking. I am wondering if the ignition module is failing or perhaps something as simple as a spark plug being faulty. I would appreciate any suggestions or ideas if you have experienced similar issues. Thanks