I let me mower sit all winter with a battery tender on it. Went to start, used some starter fluid...starts right up but won't stay running. I did this several times to see if it was just a matter of getting fuel to the carb. Never would fill the fuel filter so would always die once the starter fluid was consumed. The fuel filter on mine is normally full when running. Now it never seems to have any more than a little bit in the bottom of the filter. Not sure where to start troubleshooting.