1974 Ski-Doo Shop Manual, Page 211Get this manual
SYMPTOM: Firing on one cylinder only
Before checking circuit, make sure high tension wires and spark plugs are in working orderCDCheck cut-out button by disconnecting junction block G)and by starting engineIf both cylinders are firing, replace defective cut -out buttonIf not, proceed with following test00isconnect violet and blackviolet wiles from timing box and check pick-up coil (MAG by connecting an ohmmeter between violet and blackviolet wiresRepeat procedure for PT .0pick-up coil (BlacklYellow and VioletlYellow wires)Readings must be between 55 to 60 ohmsIf not, armature plate assembly should be replaced