Not vapor lock.
Your carburetor likely needs to be rebuilt. Float stuck/float set too high/needle valve not seating /accelerator pump leaking, etc. are possible problems.
After the engine is hot and idling, look down the throat and see if fuel is dribbling into the venturi
When it's shut off, look down the throat and see if there is fuel pooled on the intake runner. Check this hot and cold.
What type of fuel pump are you using? Test the fuel pump pressure at the carburetor. It should be 2psi-4psi. If it's greater than that, the pump could be forcing the needle valve open and flooding the carburetor.
