1974 Ski-Doo Shop Manual, Page 244Get this manual
SPARK PLUG CHART '75
ENGINE TYPEMODEL ELAN 250 (247) 250T (248) 300SS (294) OL YMPIQUE 300 (305) 340 (343) T'NT Fe 340 (343) 440 (440) EVEREST 440 (440) T'NT FA 340 (346) 440 (436) ALPINE 640 (640) ELITE 440 (434)
M175Tl W240Tl W260Tl W240Tl W260Tl W260Tl M260Tl M260Tl W280M2 W280M2 M225Tl M240Tl