1974 Ski-Doo Shop Manual, Page 128Get this manual
8Rotate magneto counter-clockwise until specified piston position before top dead center is reachedHold advance mechanism centrifugal lever in full advance position (toward magneto rim)Twist breaker points from one side to the other until timing light fluctuates (from dim to bright) or until tone signal is no longer heardRetighten retaining screw at this position If the edge gap is less than specified, loosen armature plate retaining screws and rotate armature plate ass'y counter-clockwise until correct edge gap is obtainedReset the ignition timing and recheck the edge gap If the edge gap is greater than specified, loosen armature plate retaining screws and rotate armature plate ass'y clockwise until correct edge gap is ob tainedReset the ignition timing and recheck the edge gap11Rotate crankshaft approx180 or until PTO piston approaches top dead centerDisconnect timing instru ment wire from blue wire then reconnect it to the black wire leading from engineRemove T.D.Cgauge from magside and reinstall on PTO sideRepeat steps 6, 7, and for PTO side breaker points12Remove TDC gauge from engine, disconnect timing instrument and reinstall previously removed compo nents on engine