The spring of motorcycle carburetor bounces up and presses it to install. Why is the throttle still loose?

Check whether the cable is installed correctly, whether one end is hung on the accelerator and whether the handle is hung in the slot!

There is also whether the throttle is low. If it is installed backwards, the spring will be pressed down and the throttle will be more than 60% open, so the handle will have a long free stroke.