Yamaha Marine Outboards F4A/F4 Factory Service Manual, Page 174Get this manual

BREATHER VALVE
SERVICE POINTS
Breather valve inspection 1Inspect: 9Breather valve DamageCrackbend ReplaceBreather route inspection 1Inspect: 9Breather hose (large) CrackLeakDamage Replace9Breather hole Clog Clean9Breather hose (small) CrackLeakDamage Replace

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