1978 Ski-Doo Shop Manual, Page 221Get this manual
SECTION 04 SUB-SECTION 04, (IGNITION TIMINGl
Full advance position
Rotate magneto clockwise until piston is just before top dead center With gauge in adaptor, adjust roller so that it is parallel with dial faceTighten roller lock nut
Outer ring
Adaplor lock nut
NOTE: Ignition timing can change upon tighteningAlways recheck after tightening
EDGE GAP VERIFICATION
Roller lock nut