Your moped is probably idling low. There should be a thick flathead screw, colored silver or gold on the side of the carburetor. Turn that clockwise about a turn to two turns or until the moped idles. This should make your moped idle without needed the throttle pulled.

See that brass screw near the base of the carburetor? Good, now give it two turns clockwise. Start it up and see if it needs a little more one way or the other. Should idle at about 1400 rpm

Idle circuit jet in float bowl area may be plugged up.A wire from a wire brush or compressed air may clear it to work again.Carburetor may need adjustment,engine compression may be bad.

Adjust the idle screw.