Liugong's 50CN throttle speed won't come down.

I would like to ask, "What is the reason why Liugong's 50CN throttle speed can't come down?" The reason why Liugong's 50CN throttle speed doesn't come down is:

1 and Liugong 50CN accelerator's throttle spring is compressed for a long time, and the tension is small, the throttle opening is large, and the fuel supply is increased, which leads to the slow return of the speed pointer.

2. There is something wrong with Liugong 50CN accelerator accessories;

3. Liugong 50CN throttle air inlet will leak.