Overhauled carbuerator, changed spark plug, changed air filter changed fuel filter. Started up and ran approx. 30 seconds died and won't start back up

Hi,
Sounds like a fuel delivery problem. Check the carb for an unattached wire to the fuel shutoff solenoid, if so equipped. It can be checked by removing the air filter and pouring a small amount of fuel into the carb to see ifit cranks. Also I will point out that few plugs come gapped correctly at 0.030"
Peace,
Clarke