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Sierra 18-6243 Zinc Gimbal Housing Anode for MerCruiser Sterndrive 821631Q1

Manufacturer

Sierra

<h3>Sierra: Six Decades of Marine Aftermarket Excellence</h3><p><strong>Sierra</strong> has spent nearly 60 years earning its reputation as one of the most trusted names in the marine aftermarket industry. Originally focused on engine and drive components for boats, the brand has grown into a comprehensive source for nearly everything a boater needs to keep their vessel running at its best — from precision instrumentation to complete engine rebuild hardware.</p><p>Now operating as a brand of Dometic, Sierra manages global aftermarket distribution from a 300,000 sq. ft. facility in Litchfield, Illinois. The Sierra brand today encompasses not only its flagship marine parts line but also well-established marine names like Shields and Moeller, offering boaters a broader catalog than ever before. Whether you own an outboard, inboard, or sterndrive, Sierra's engineering team designs products to meet or exceed OEM specifications.</p><h3>Precision Instrumentation You Can Trust on the Water</h3><p>One of Sierra's most recognized product areas is its marine instrumentation lineup. The brand's <a href="/7570-sierra-gauge-set-1480">gauge sets</a> cover everything from classic analog instrument clusters to advanced digital multi-function displays. Sierra offers packages suited to outboards, sterndrives, and gasoline-powered inboards, with options ranging from coordinated analog kits in styles like Arctic, Eclipse, and Amega to modern touchscreen solutions like the R3 multi-function gauge. Features such as scratch-resistant domed glass lenses, silicone-dampened pointers, and perimeter backlighting make these instruments highly readable in all conditions.</p><p>Behind every accurate gauge reading is a properly calibrated sending circuit. Sierra's <a href="/7570-sierra-gauge-resistor-47908">gauge resistors</a> are a critical part of that chain, ensuring the signals from sensors and sending units are correctly interpreted by your instruments. These components are built to marine-grade standards to resist moisture, vibration, and corrosion — the realities of life on the water.</p><h3>Engine Internals Built to OEM Standards</h3><p>Sierra's history in marine power is perhaps best demonstrated by its deep catalog of engine components. The brand's <a href="/7570-sierra-engine-gasket-set-5404">engine gasket sets</a> cover a wide range of outboard and inboard applications and are engineered to deliver reliable seals in the demanding thermal and chemical environment of a marine engine. For boaters performing seasonal overhauls, top-end rebuilds, or full engine restorations, Sierra gasket kits are a go-to resource trusted by professional marine technicians and DIY boaters alike.</p><h3>A Complete Marine Parts Partner</h3><p>Beyond instrumentation and engine internals, Sierra's catalog spans fuel systems, electrical supplies, steering components, shore power, and more — all covered by what the brand calls an industry-leading warranty. Sierra also maintains a comprehensive parts-finder tool that enables cross-referencing with OEM part numbers from major manufacturers including Mercury, Yamaha, Suzuki, Volvo Penta, and others, making it straightforward to find the right replacement part for virtually any application.</p>

Part Number

18-6243
09/11/2036 2:23 AM
Sale Price

$40.26

In Stock (6)

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Usually delivered within 2 days

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Product Details

The Sierra 18-6243 is a zinc gimbal housing anode designed as a direct replacement for MerCruiser sterndrive applications. This sacrificial anode mounts at the base of the gimbal housing and works by attracting galvanic corrosion away from critical metal components, including shafts, propellers, rudders, and drive components — allowing the anode itself to deteriorate while protecting the surrounding hardware.

Key Features:

  • Zinc construction — ideal for saltwater and brackish water environments
  • Replaces OEM Mercury/MerCruiser part numbers 821631Q1, 821631A1, 821631B1, 97-821631C, 43994A2
  • Mounts at the gimbal housing on MerCruiser R, MR, and Alpha One sterndrive assemblies
  • Fits over the trim line manifold for a secure, OEM-style installation
  • Manufactured to meet or exceed OEM corrosion protection standards
  • Protects shafts, propellers, rudders, and other underwater drive components from galvanic corrosion

Important Note: Zinc anodes are recommended for saltwater and brackish water use. For freshwater applications, a magnesium anode is the preferred material choice.

Sierra marine parts are manufactured to meet or exceed OEM specifications, ensuring reliable, long-lasting corrosion protection for your MerCruiser sterndrive system. Inspect the anode regularly and replace when signs of significant deterioration or pitting are observed.

Thanks

Simple and fast

Great A++

Quick ez process.

if it went any better i could do it in my sleep . it's great doing business with you .

I hope this thing is awesome

It was fast and easy.

Great experience. I would definitely recommend.

Great

Saved me $150 over Mopar brand fan assembly for my 2005 300C 5.7 HEMI. Delivery was extremely quick, the part was a perfect fit, and working as expected. Thank you!!!

Great prices, fast shipping. Would recommend.

Great product and speedy service!

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