Mercury – Quicksilver Trim Tab Anode | Freshwater Corrosion Protection & Steering Aid | Cast Magnesium | 31640T6

Overview

If you boat exclusively in freshwater, the Mercury Marine 31640T6 Quicksilver Magnesium Trim Tab Anode offers the best possible protection for your engine and drive. Designed for Mercury and Mariner outboards (35HP and above) and MerCruiser sterndrives (except Bravo), this anode shields vital components from galvanic corrosion while also helping balance steering torque. Made from high-purity magnesium, it sacrifices itself to protect your engine’s metal parts — keeping your gearcase clean, smooth, and protected year after year.

Key Features

• Purpose: Prevents galvanic corrosion in freshwater by protecting gearcase and drive components.
• Material: Made from cast magnesium, offering the most effective corrosion protection in low-conductivity water.
• Design: Functions as both a trim tab and an anode, reducing steering torque and improving handling.
• Performance: Meets or exceeds MIL-A-21412(SH) military standards for magnesium marine alloys.
• Installation: Fits easily using existing hardware; check for propeller clearance before use.
• Compatibility: For Mercury and Mariner outboards (35HP and up) and MerCruiser sterndrives, excluding Bravo models.

Engine & Boat Compatibility

• Fits Mercury and Mariner outboards 35HP and larger.
• Works with all MerCruiser sterndrives except Bravo drives.
• Best suited for freshwater boats — pontoons, fishing rigs, runabouts, and sport boats.
• Designed specifically for freshwater corrosion protection, not for salt or brackish water use.

Performance & Practical Benefits

The 31640T6 magnesium anode is your engine’s first line of defense in freshwater. Magnesium is more active than aluminum or zinc, making it ideal for the low-electrolyte conditions of lakes and rivers. It sacrifices itself to corrosion, sparing your lower unit, prop, and hardware from damage.

The hydrodynamic shape doubles as a trim tab, helping offset prop torque and improve steering control. It installs quickly with standard tools and begins working immediately, giving you visible peace of mind each time you inspect your gearcase.

Why Buy OEM

Mercury’s Quicksilver 31640T6 is a genuine OEM anode, engineered for exact fit and proven performance. Aftermarket anodes may not meet military specifications for magnesium composition, meaning they wear unevenly or don’t provide full protection.

Mercury’s manufacturing standards ensure each anode provides consistent corrosion prevention, a clean fit, and steady steering assistance. It’s the smart choice for boaters who rely on Mercury performance and want long-term peace of mind in freshwater conditions.

FAQ

Q1: Where should this anode be used?
It’s designed for freshwater only — not recommended for saltwater or brackish environments.

Q2: Which engines and drives does it fit?
It fits Mercury and Mariner outboards (35HP and up) and MerCruiser sterndrives, excluding Bravo.

Q3: What material is it made from?
It’s made from high-purity cast magnesium, meeting MIL-A-21412(SH) standards.

Q4: How does it help steering?
The trim tab shape reduces steering torque, making handling easier and smoother.

Q5: How often should it be replaced?
Inspect the anode a few times each season and replace when it shows pitting or about 50% wear.

• Supersessions
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