If you spray carburetor spray into carb, and it starts briefly and dies, most likely a fuel related issue.
Possible causes:
Gas cap not venting properly
Fuel pump
Fuel lines clogged
Vapor lock
Anti-afterfire solenoid on carb
Water in fuel
Dirty carburetor
And more…
So you see it is difficult to sometimes diagnose, and is a process of elimination until success is achieved.