Yamaha Outboard Motors Factory Service Manual F6 and F8, Page 134Get this manual

GENERAL GENERAL CHECKING THE ANODE
Check: Anode (engine side) Anode (lower unit) Scales CleanOilgrease CleanExcessive weardamage

Replace
CAUTION:

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