The starter motor solenoid switch is mainly composed of a solenoid mechanism and a motor switch. The solenoid mechanism consists of a fixed iron core, a movable iron core, an attracting coil and a holding coil. The fixed iron core is fixed, and the movable iron core can move axially in the copper sleeve. The front end of the movable iron core is fixed with a push rod, the front end of the push rod is mounted with a switch contact plate, and the rear section of the movable iron core is connected with the shift fork through an adjusting screw and a connecting pin. A reset spring is mounted on the outside of the copper sleeve for resetting the movable parts such as the movable iron core. The arrangement of the starter motor solenoid switch terminals is shown in the figure