Electromagnetic selector valve system

An electromagnetic selector valve system having an electrically conductive coil adjacent a moveable core within a valve body. First, second and third valve passages are in communication with the valve body, and biasing means are adapted to bias the reciprocative core to assume a first position wherein the core permits communication only between the first and third passages. Upon energizing the electrically conductive coil, the core assumes a second position which permits communication only between the first and second passages. In a preferred embodiment, the electromagnetic selector valve is utilized in order to control the spark advance of an engine.