My Account
Shopping Cart

Sierra 18-2172 MerCruiser GM V6/V8 Engine Coupler Replaces 14505A2

Manufacturer

Sierra

<p>For nearly six decades, Sierra has established itself as one of the marine industry's most trusted names in aftermarket engine and drive parts. Founded as a specialized marine parts manufacturer, Sierra has grown into a comprehensive supplier of replacement components, instrumentation, and accessories for both recreational and commercial boating applications. Operating from their 300,000-square-foot distribution center in Litchfield, Illinois, Sierra serves boat owners and marine technicians worldwide with an extensive catalog of parts engineered specifically for the harsh saltwater environment.</p><h3>Marine Engine Excellence</h3><p>Sierra's reputation was built on delivering precision-engineered internal engine components and drive system parts that meet or exceed OEM specifications. Their <a href="/7570-sierra-engine-gasket-set-5404">engine gasket sets</a> provide critical sealing solutions for inboard and outboard motors, while their <a href="/7570-sierra-engine-complete-assembly-15341">engine complete assemblies</a> offer comprehensive replacement options for major overhauls. Each component undergoes rigorous testing to ensure reliability in demanding marine conditions, from corrosion resistance to temperature cycling performance.</p><h3>Instrumentation and Monitoring Systems</h3><p>Accurate instrumentation is essential for boat operators to monitor engine health and prevent costly breakdowns on the water. Sierra's comprehensive line of <a href="/7570-sierra-gauges-200483">gauges</a> includes everything from fuel pressure and temperature indicators to voltmeters and trim gauges, all designed with marine-grade materials that withstand vibration, moisture, and UV exposure. Their <a href="/7570-sierra-tachometer-gauge-1488">tachometer gauges</a> deliver precise RPM readings critical for optimizing engine performance and fuel efficiency. Supporting these instruments, Sierra's <a href="/7570-sierra-gauge-resistor-47908">gauge resistors</a> ensure proper signal conditioning and accurate readings across various sensor types and engine configurations.</p><h3>Expanded Product Portfolio</h3><p>In 2022, Sierra significantly broadened its scope beyond traditional marine engine parts to encompass a wider range of boating accessories and even outdoor power equipment components. This strategic expansion brought established marine brands like Shields and Moeller under the Sierra umbrella, creating a one-stop resource for marine maintenance and replacement parts. The company now offers fuel systems, electrical components, battery charging solutions, and NMEA electronics alongside their traditional engine parts lineup.</p><h3>Quality Backed by Industry-Leading Warranties</h3><p>What sets Sierra apart in the crowded aftermarket marine parts market is their commitment to standing behind every component they manufacture. Their warranty coverage extends beyond simple part replacement—it includes shop labor, haul-out fees, towing charges, and related incidental costs should a warrantied part fail. This comprehensive protection reflects the company's confidence in their manufacturing processes and quality control standards. For boat owners facing repairs far from shore or mechanics working on customer vessels, this peace of mind is invaluable. Whether you're maintaining an outboard motor, rebuilding an inboard engine, or upgrading your boat's instrumentation, Sierra's decades of marine industry experience and commitment to quality make them a reliable choice for keeping your vessel running at peak performance.</p>

Part Number

18-2172
07/14/2036 2:57 AM
Sale Price

$362.67

3 left at this price

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 18-2172 Engine Coupler is a heavy-duty aftermarket replacement coupler designed for MerCruiser stern drive applications. This coupler serves as the critical mechanical link between the GM inboard engine and the stern drive unit, transmitting power from the engine flywheel to the drive system.

This part is specifically engineered for use during engine upgrades or replacements — it is required when swapping an older GM V6 or V8 engine with a 2-piece rear main seal and a 3-1/2" crankshaft bolt pattern to a newer 1-piece rear main seal engine with a 3" crankshaft bolt pattern. Without this coupler, the bolt patterns of the old and new engine configurations are incompatible.

Key Features:

  • Direct replacement for MerCruiser OEM part number 14505A2
  • Designed for MCM GM V-6 and V-8 engines (305 and 350 cid)
  • Manufactured to meet or exceed original OEM specifications
  • Mounting hardware (studs, washers, and nuts) included
  • Cross-references: GLM 11520, Mallory 9-72500, OMC 775495

OEM Cross-Reference Part Numbers: MerCruiser 14505A2 | GLM 11520 | Mallory 9-72500 | OMC 775495

Sierra is the market-leading brand for aftermarket marine engine parts, offering a comprehensive product line backed by a customer satisfaction warranty covering parts and labor. This coupler is a dependable, cost-effective solution for any Pre-Vortec MerCruiser stern drive engine swap or rebuild.

Good

easy to find and order

Very good

Wow, first time I ordered and they hit a homerun with me!! Shipped same day I ordered AND was the cheapest option I had including shipping. I'll be back. Thanks for the great service!!

easy to order. just kinda bummed i didn't get to use my '30offtshipping' discount i got in my email. it wouldn't accept it. shipping was fast! very pleased with the shopping experience with Autoplicity.com

Shipping took a little longer than quoted

Great Clutch kit I got, did have to contact customer sevice to see if my item shipped but was very nice about it. I would do business with them again. Item shipped quickly. Great price to.

Very friendly site makes shopping an esay experience

Very quick and easy with PayPal..Bought here because they use PayPal

Easy checkout with Amazon

Had what I wanted. Shipped quickly. Very pleased.

Best prices anywhere!!!

Good price.

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