1970-1979 Ski-Doo Snowmobiles Service Manual, Page 28Get this manual

PERIODIC MAINTENANCE AND TUNE-UP

SPARK PLUG CONDITIONS

NORMAL USE

OIL FOULED

CARBON FOULED

OVERHEATED

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