Wasn't attacking you Joe. No reason too, I did reply to mihe. And this one does also.
mihe, did your engine start easily, always? That would eliminate a bad fit on the timing disk. Pulse port blockage, fuel pump issues.
Did fuel remain in the line after shut down? Always?
Did the engine die suddenly? In level flight? If so it starved for fuel or the ignition died. Bad plug. Klunk stuck forward. etc.

Were you able to turn the engine over after the flame out? Does it still have compression? Did it smell or feel hot?
The diaphram and fork heigth provide the needed fuel reservoir for the engine to draw fuel through the needles. Have you removed the diaphram and inspected those parts? The reservoir meter, high and low needles, and timing all have to be right for good power to be made.
How much clearance does the carb intake have? Not backed up against the firewall?
Have you checked the timing? Ever adjusted it for best opperating location?
Many more questions if these don't seem to point to a cause..