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Sierra 18-3318 Marine Water Pump Kit for MerCruiser I/O Engines

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

18-3318
09/12/2036 9:23 AM
Sale Price

$84.20

In Stock (10)

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Usually delivered within 2 days

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FREE SHIPPING

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No Hassle Returns

Live-in-stock inventory

Live-in-stock inventory

Fitment guaranteed

Fitment guaranteed

Product Details

The Sierra 18-3318 Water Pump Kit is a complete sea water pump service kit designed for MerCruiser inboard/outboard (I/O) engines. This kit provides everything needed to rebuild both plastic 1-piece and 2-piece sea water pump bodies, making routine water pump maintenance straightforward and cost-effective. It directly replaces Mercury Marine OEM part number 47-59362Q08.

Kit Contents:

  • Impeller – Sierra 18-3087 (single flat, compatible with 1-piece and 2-piece pump shaft)
  • Wear Plate – Sierra 18-3350
  • Wear Plate – Sierra 18-3351
  • Water Pump Body Gasket – Sierra 18-0386
  • Water Pump Gasket – Sierra 18-0916

Key Features:

  • Direct replacement for Mercury Marine / MerCruiser OEM part 47-59362Q08
  • Compatible with plastic 1-piece and 2-piece sea water pump bodies
  • Impeller compounds formulated specifically for size and marine application
  • All components engineered to meet or exceed OEM specifications
  • Assembled to Sierra's quality standards for superior marine performance

Sierra is a trusted name in aftermarket marine parts, offering premium-quality replacements engineered to meet or exceed OEM standards. The 18-3318 kit simplifies MerCruiser sea water pump servicing by supplying all critical wear components in a single package. UPC: 808282184544.

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