please help!!

The device you see is part of the governor system and is suppose to move back and forth as the engine slows and accelerates. It is not the cause of your problem but the results of your problem.

Have you checked things like fuel flow, electrical problems, blocked air passage ways, etc. When was the last time the tactor was serviced?

If you do not know how to do these things you need to read a basic book on small engine. Failing that you may have to have your local John Deere Dealer look at it. Check the label on one of the new John Deere tractors at Lowes, to find the closes JD Dealer that does repair work. The John Deere Dealer will have all of the technical knowledge and parts to service your mower.

Thanks for reply, It was bad fuel per service man.