Mercury Mariner 8/9.9HP 4-Stroke Factory Service Manual, Page 21Get this manual
Corrosion Control Anode The anode (a) requires periodic inspection especially in salt water which will accelerate the erosionTo maintain this corrosion protection, always replace the anode before it is completely erodedNever paint or apply protective coating on the anode as this will reduce effectiveness of the anodeIMPORTANT: DO NOT paint or place protective coating on anode (or the contact surface on the drive) or corrosion protection is lost
2Attach water hose to the flushing attachmentTurn on the water and adjust the flow so water is leaking around the rubber cup to ensure the engine receives an adequate supply of cooling water
3Start the engine and run it at idle speed in neutral shift positiona 4Adjust water flow (if necessary) so excess water continues leaking out from around the rubber cup to ensure the engine is receiving an adequate supply of cooling water
5Stop engineTurn off waterRemove flushing at-