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The Importance of Anodes

Anodes, also called sacrificial anodes, are designed to attract corrosion-causing electrical currents, keeping them away from your boat motor, and therefore, preventing your motor from corroding. There are two located on each engine, one on the lower unit just above the prop, and another below the engine bracket.


When two different metals are physically or electrically connected and submerged in water, they act as a battery, allowing current to flow. This current can escape into the water and corrode any metal in its vicinity. The electricity is attracted to the most reactive metal, therefore Yamaha anodes are made from a blend of high-quality alloys that are specially designed to attract the electricity and prevent it from going into and corroding your motor. Over time, the electricity dissolves the anodes and they need to be replaced. The amount of time it takes for anodes to dissolve depends on several factors including boat usage, location, and the type of water found where the boat is used.


To keep your anodes working properly, never paint or cover them. Each time you flush and washdown your motor brush them with soap and water to prevent scum buildup. When the anodes are about 50% depleted have your dealer replace them.