1983 Ski-Doo Shop Manual, Page 204Get this manual
SECTION 04 ELECTRICAL SUB-SECTION 02 (IGNITION TIMING)
To adjust, remove rewind starter assembly and starter pulleyLoosen the armature plate screws, move the plate in the appropriate direction
Back-off (rotate counter-clockwise) piston to: 464 engine type: 2.52 mm (0.099") BTDC 534 engine type: 1.75 mm (0.069") BTDC BTDC: before top dead centerLook through inspection hole and check if flywheel and magneto housing timing marks alignIf the marks do not correspond to the specifications, scribe new mark on the magneto housing
'-""Marks should align
Tighten armature plate screws CAUTION: Make sure armature plate screws arewell securedReassemble starter pulley and assemblyRecheck engine timing (make sure engine is cold)
Stroboscopic timing light
NOTE: Timing can be checked using stroboscopic timing light (Electro Specialty 978, Snap-On MT 212 or equivalent)The ignition components are affected by temperature variation, therefore, timing must be checked when engine is cold