I don't know if you have a fuel solenoid on the carb. If it does, next time it die turn the key off and back on to see if the solenoid clicks or not. If no click replace solenoid. If it clicks, then try to restart, if it restarts run until it dies again, but this time try to restart without turning the key off. if it doesn't start , then turn key off then back on to see if it starts then. If it restarts then, remove the fuel solenoid, and if it has the plastic plunger tip, gently pull on the plastic tip and see if it comes off. If it slids off, you can either replace the solenoid, epoxy the tip on, or run the mower without the tip.
If you find no problems with the solenoid, then next time it dies, quickly clamp off the fuel line, and let the engine cool. Then remove the fuel bowl to see if it has fuel in the carb. If empty then you have a fuel delivery problem someplace between the tank and the carb bowl. Could be dirt in tank plugging outlet, to a sticking float needle valve.
