Mercury Anodes & Zincs

Anodes are a critical component for preserving the health of a boat. Whenever two different types of metal (steel and bronze, for example) are in physical contact and submerged underwater, they create a small electrical circuit that causes electrons to transfer from one to the other. The metal that gives up electrons eventually corrodes and crumbles into nothing. An anode prevents this corrosion by introducing a third metal to the circuit that gives up electrons more easily. If you have a Mercruiser engine, it’s critical that you use Mercruiser anodes and zincs.

Anode Materials (Aluminum, Magnesium, Zinc)

The three most common types of metal used in anode kits are zinc, magnesium, and aluminum. Historically, zinc has been the most common for this application, to the point that some boaters and mechanics simply refer to this entire category of parts as “zincs.” However, other types of metal, including aluminum and magnesium, are used as anodes as well.

What type of metal is used depends on what conditions the boat is used in. Magnesium anodes are best used in fresh water, where they enjoy greater longevity and their lighter weight can lead to fuel savings. Zinc anodes, on the other hand, do best in salt and brackish water, where they have a higher density and stronger structural composition, providing significantly higher impact strength. Mercury anodes also come in aluminum.

What is the best anode for saltwater?

Today, many Mercury zincs are actually made from aluminum. This is because aluminum is often cheaper than zinc, meaning you will spend less on maintenance. Another major reason behind the transition from zinc to aluminum anodes is environmental concerns; zinc anodes spread cadmium in the water, which in turn creates health problems for aquatic flora and fauna. As aluminum does not spread cadmium, it is more environmentally friendly. These qualities mean that aluminum is quickly becoming the preferred type of metal for anodes in saltwater and brackish water.

How to replace Mercruiser anodes?

Replacing Mercruiser anodes and zincs is a relatively easy process for both i/o and onboard engines. Whichever Quicksilver Mercury anode you use, it will often come with screws and bolts that secure it in place. This means that in most cases, replacing anode kits is a simple task of unscrewing the old anodes, removing them, and securing the new anodes in their place. When replacing anodes, there are two priorities. First, electrical contact must be made, meaning consistent metal-to-metal physical contact. Secondly, anodes must not be covered with paint. Doing so smothers the anode and makes it useless.

Anode Part Compatibility

You’ll want to follow the first rule whenever you’re shopping for new Mercruiser parts: making sure they’re compatible with your boat’s engine. With our comprehensive inventory of Mercruiser components, we are prepared to help you resolve any boat maintenance or repair issue you may have. All Mercruiser anodes we offer are guaranteed to be OEM-certified, so you can always be sure of the compatibility of whatever anodes you use.