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Sierra 18-3424 Water Pump Base for Mercury Marine Outboards

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

18-3424
09/12/2036 8:13 AM
Sale Price

$37.20

In Stock (10)

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Usually delivered within 2 days

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Product Details

The Sierra 18-3424 is a replacement water pump base designed for Mercury Marine and Mariner outboard engines. This component forms the structural foundation of the outboard's raw water cooling pump, providing a precise-fit, drop-in replacement for the original Mercury part number 46-77177A1.

Sierra International is a leading manufacturer of marine aftermarket parts, engineering their components to meet or exceed OEM specifications. The 18-3424 water pump base is built to restore proper cooling system function and is commonly used during water pump service or impeller replacement intervals.

Key Features:

  • Direct OEM replacement for Mercury Marine water pump base
  • Replaces Mercury/Quicksilver OEM part number 46-77177A1
  • Also cross-references with GLM 12030 and Mallory 9-43300
  • Compatible with Mercury and Mariner 2-stroke outboard engines ranging from 35 HP to 70 HP
  • Sold as a single water pump base unit
  • Also available as part of the Sierra 18-3324 complete water pump housing kit

Verify fitment using OEM part numbers before ordering. This part is UPC 808282230449.

Excellent service

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Price was much lower than any other parts dealer. Even with standard shipping, the parts arrived in a couple of days. Would use autoplicity again. Absolutely no problems.

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This is my first time ordering from them, but it certainly will not be my last. They have all the parts I need and the process and ship fast. Great company. And they're prices are awesome.

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Easy to order

Excellent on-line merchant with outstanding customer service and the best prices on equipment and shipping. Highly reccomended!

Placed order on Tuesday late afternoon, item shipped next day. One of the fastest turn around times I expereniced online yet. Thank you

Good. Fast shipping

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