Mercury Mariner 4 and 5HP 4-Stroke Outboards Service Shop Manual 1999, Page 107Get this manual

CYLINDER HEAD
Adjustments
Valve Clearance
IMPORTANT: Make all valve adjustments while engine temperature is coolNOTE: Inspect cover gasket for cuts or tearsReplace gasket if damaged57252

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