An adjusting device for adjusting a stop lever coupled with a control device of an internal combustion engine. The adjusting device includes a housing having an electric motor which via a worm gear rotates a gear wheel. An internal thread is provided in an inner bore of the gear wheel and is engaged by the external thread of a spindle. The spindle is joined to an actuating sleeve and on one end has struts extending in the axial direction, which protrude into guide grooves of a short tubular portion of the bottom part of the housing and are displaceable therein in order to secure the spindle against rotation. A feeler is slidably disposed in the actuating sleeve and when the stop lever of the control device is in contact with the feeler, the feeler closes switch contacts which communicate via wiper fingers with contact paths, which are disposed on a protuberance which extends into the spindle.