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Sierra 18-1157 Forward Gear Inner Bearing for Mercury Marine & Honda 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

18-1157
09/12/2036 6:27 AM
Sale Price

$17.19

1 left at this price

delivery box

Usually delivered within 2 days

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No Hassle Returns

No Hassle Returns

Live-in-stock inventory

Live-in-stock inventory

Fitment guaranteed

Fitment guaranteed

Product Details

The Sierra 18-1157 is a Forward Gear Inner Bearing designed as a direct replacement for Mercury Marine and Honda outboard lower unit gearcase assemblies. This aftermarket bearing is manufactured to meet or exceed the original equipment specifications it replaces, ensuring a proper fit and reliable performance in the marine environment.

Key Features:

  • Direct OEM replacement forward gear inner bearing
  • Meets or exceeds original equipment specifications
  • Designed for use in lower unit gearcase assemblies
  • Compatible with a wide range of Mercury/Mariner, Mercruiser, and Honda outboard applications from 30–250 HP
  • Manufactured by Sierra, the market leader in aftermarket marine engine parts

Replaces OEM Part Numbers:

  • Honda: 91057-ZW1-003
  • Mercury Marine: 31-30895, 31-30895T

Sierra International is a trusted supplier of aftermarket marine parts, providing comprehensive coverage across all major engine brands with an unsurpassed customer satisfaction warranty covering parts and labor.

Great place. Wish some idems had more detailed descriptions.

It took over 30 min to place this order. your pay site has problems.

the service is #1 they keep you inform of the status of your order the prices are lower than those e internet sites<br>they go against the best and come out winning.<br>

Exactly what I ordered for the best price and fast, too!

Ordered Sunday and recieved product Tuesday .. What more can u ask for? Great Seller!

so far so good

Your site looks professionally constructed and has an easy to understand interface.

Tank You!! Thank you very much

Very easy system. I hope the shipping is fast too.

Quick and to the point. No signing up for email newsletters and all that junk. Great shipping rates as well

Simple checkout process

Best price on the web (order#10369). Fast order and they had the products I wanted. Will recommend and purchase again from them.

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