3000W Chinese Gensets Info.

I am a new subscriber to the site and I must say I am impressed with the patience and collaborative efforts here. I have been looking around for a generator for quit some time, Hurricane Rita pushed me to make a purchase rather quickly. With this being said, I would like to see if anyone has had a similar problem with their generators. I have a Nokita 3500w, purchased from PeP Boys that ran great for 48 hours then stopped producing power. The motor seems to be running at a slower speed with or without load. When I plug a test device (wall plug tester w/ three lights) into the socket, it only lights when I manually increase the throttle. Could the idle screw have backed off due to vibration? Should the generator produce power at a lower run speed? I may just take it back to see if I can get a replacement but would like to forgo the effort if it's something simple.....gas is not cheap these days!! Any info or assistance would be greatly appreciated.