1989 Ski-Doo Repair Manual, Page 377Get this manual

Section 04 ELECTRICAL SYSTEM Sub-section 03 (SPARK PLUGS)
NGK SPARK PLUG TYPE
All models except Elan

SPARK PLUG NUMBERING SYSTEM

• ATV
• Jet Ski
• Outboard Motors
• Personal Watercraft
• Snowmobiles
• Stern Drives