Cant get generator engine to keep running.?

I bought a small 1500 watt generator with a 2.8 hp. overhead valve gas 4 stroke engine (made in china). Filled crankcase with oil and filled tank with gas. engine started first pull of starter rope. I let run for approx 10 minutes. I then plugged in (2) 100 watt lamps and a small box fan. Generator ran great. After about 5-6 minutes I unplugged all. Generator was running with no load for approx 5 minutes and then just quit like it had been turned off. Would not restart just hit every once in awhile. Replaced spark plug and ignition spark module. It started then immediatly quit again. Replaced carburator, it started and ran good for approx 5-6 minutes and quit again.

Is there any other ignition component in there that could develope a open circut after warming up?