Small Engines (Lawn Mowers, etc.): KIPOR model KGE 3000 TI problems

Question
I have a Kipor Sinemaster KGE 3000 TI generator. It is about 6 years old and has always run perfectly. Now runs ok at idle speed or small (1000 watt ) draw.  As soon as a large draw occurs the engine dies.  Also sometimes, not all the time after approximately 15 minutes even at idle speed the engine will quit.  I have replaced the carb, spark plug, and cleaned the fuel tank.  No change.  Any suggestions.  What about the stepping motor?

Answer
Did you check the resistance of the stepping motor per the service manual page 26?

Service manual URL:

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0CCwQFjAC&url=http%3A%2F%2Fwww.generatoremporium.com%2Fpdf%2FIG3000-service.pdf&ei=hjYFVPKBCYbPggTCtYCgBw&usg=AFQjCNGTei7Vhcea11qpirQWQxbgUj5BCQ&sig2=UjQCUtrniwauWOGDPZkIXg

Eric