My Account
Shopping Cart

Sierra 18-3714 Brass Castle Washer for Mercury MerCruiser Propellers

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

18-3714
06/01/2036 5:16 PM
Sale Price

$10.30

In Stock (10+)

delivery box

Usually delivered within 2 days

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 18-3714 is a brass castle washer that supports the prop nut and locking tabs on traditional rubber hubbed propellers. This precision-engineered marine hardware replaces Mercury MerCruiser OEM part numbers 12-31211, 12-31211A2, 12-31211A3, and 12-31211Q03.

Compatibility:

  • Fits Mercury/Mariner 135-275 HP (V6, 2-cycle) outboards
  • Compatible with MerCruiser Alpha and Bravo I stern drives without Flo-Torq II Hub
  • Designed for all traditional rubber hubbed propellers
  • Not used with newer style Flo-Torq II or Michigan Vortex style propellers

Key Features:

  • Constructed from durable brass material for corrosion resistance in harsh marine environments
  • Precision-manufactured to meet or exceed OEM specifications
  • Essential component for secure propeller installation and retention

Interchangeable With: GLM 21360, Mallory 9-73902, and various Mercury/MerCruiser part numbers. This genuine Sierra replacement part ensures reliable performance and proper fitment for your marine propulsion system.

This copany shipped my order promptly. I would do business with them again.

very good

Fast shipping, the exhaust fit perfectly and sounds great!

Good experience,east to navigate site,easy checkout,very good price!

They are excellent. They were able to send out my item as early as the next day. I am anticipating my product by early next week. Great!

Nice and quick. Well scripted to take customer info straight from paypal. That was what...4 clicks? Nice!

Very competitive low prices and great product selection. Will definitely look to this vendor when purchasing automotive parts in the future.

Great price & part in stock & was told would ship today !

Item arrived as ordered and they had the lowest price!

One of the best prices on the web for my Bilstein shocks. And super fast shipping! I ordered on a Mon night and they arrived Wed afternoon!!

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