Mercury Mariner 4 and 5HP 4-Stroke Outboards Service Shop Manual 1999, Page 154Get this manual

CYLINDER BLOCK AND CRANKCASE
2Install the breather tubes and wave washers
aBreather Tube (2)

bWave Washer (2)

3Install the breather cap

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