Started up mower this season after sitting all winter with fuel in the tank. Engine will start up for a few seconds very robustly and then sputter out. It was running last season, not perfectly but no interruptions.
Replaced spark plug, took apart gas tank, fuel lines, carb, air filter. Used carb cleaner where appropriate. Everything seems to be clear and working properly. The only thing we weren't able to take apart was where the fuel line meets the carb at this little plastic joint that's shaped like an L. We did spray carb cleaner in there though.
Anyway we did all that, still won't run and in fact it wouldn't even start up unless we poured fuel directly into the carb, even with the gas cap off it ran a little longer but still died.