My Account
Shopping Cart

Sierra 118-21752-1 Marine Engine Coupler for OMC Cobra & Volvo Penta

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

118-21752-1
09/12/2036 4:34 AM
Sale Price

$238.18

In Stock (5)

delivery box

Usually delivered within 2 days

free shipping

FREE SHIPPING

Authorize Seller Badge
No Hassle Returns

No Hassle Returns

Live-in-stock inventory

Live-in-stock inventory

Fitment guaranteed

Fitment guaranteed

Product Details

The Sierra 118-21752-1 is a premium aftermarket marine engine coupler designed to connect GM V6 and V8 engines to OMC Cobra and Volvo Penta SX stern drives. This critical drivetrain component features a 17-spline design and is engineered for one-piece rear main seal engines with a 3-inch crankshaft bolt pattern circle.

Key Features:

  • Direct replacement for OMC part numbers 3858437, 984290, 986120, and 3853917
  • Compatible with Volvo Penta part numbers 3853917 and 3858437
  • Engineered to meet or exceed OEM specifications
  • 17-spline design for positive engagement
  • Manufactured from quality materials for harsh marine environments

Engine Compatibility:

  • 4.3L engines (1986-1998)
  • 5.0L engines (1986-1988, 1998)
  • 5.7L engines (1986-1992, 1994, 1996-1998)

Sierra Marine is a trusted leader in aftermarket marine engine parts, delivering quality components backed by comprehensive customer satisfaction warranties. This engine coupler is essential for transferring power from your engine to the stern drive unit.

Very easy traction. Will be ordering again.

Very good service

Thanks

Fast

It was what it should be Thank You Art

As described and rapid delivery.

quick and easy great price

SUPER EASY &amp;amp; great price assuming tires arrive on time as advertised

Wow, the price was unbeatable and the delivery was quick. The props came in perfect condition, couldn't be happier.

Share icon
Return Policy
Returns are easy at Boatplicity

Not happy with a purchase? No problem. We've made returning items as easy as possible. And most purchases can be returned for free for 30 days. Learn more about our Returns Policy