Try running it without the fuel tank cap on and see if it cuts out then. If not then you have a breather blockage in the fuel system causing a vacuum- thus impeding the fuel flow after it has been running for a short while.
pleasant, September 2008
First change the plug (again) it's not unknown for a new plug to be flakey.
If that doesn't work, suspect a coil fault. They can fail when hot.
