My champion 2000w inverter generator is not running properly. It starts fine in the choked position, but when I rotate the selector to run position, the rpm's run high to the point the engine is rattling out of control. If I put it back in the choke position, the rpms climb back down almost to idle. It won't put out power. Im assuming this is some sort of safety feature? The generator was last fired up in early spring. The fuel has been sitting in the carburetor and tank. I'm thinking I need to pull the carburetor and completely clean it out. What would you guys advise? It was running perfectly last camping trip. I need to figure it out soon as I'm going camping in a week. Thanks for all the help you guys always give.