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Sierra 18-3787 MerCruiser Bravo III Rear Propeller Tab Washer

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

18-3787
07/13/2036 9:15 AM
Sale Price

$26.88

1 left at this price

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Usually delivered within 2 days

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No Hassle Returns

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Live-in-stock inventory

Fitment guaranteed

Fitment guaranteed

Product Details

The Sierra 18-3787 is a replacement rear tab washer designed for MerCruiser Bravo III sterndrive systems. Tab washers are a critical mechanical locking component used to secure propeller shaft fasteners, preventing the prop nut from backing off under load and rotation during operation.

Tab washers work by positioning between the mating surface and the prop nut, with a notch or tab that physically restricts rotation relative to the shaft — providing a reliable, positive-lock retention method without relying solely on friction or torque.

Key Features:

  • Designed specifically as the rear tab washer for MerCruiser Bravo III sterndrive applications
  • Provides positive mechanical locking of the rear propeller nut to prevent loosening under load
  • Manufactured by Sierra International to meet or exceed OEM quality standards
  • Direct replacement for the original MerCruiser tab washer on Bravo III drives
  • Essential component for proper propeller retention and safe sterndrive operation

Sierra International is a leading manufacturer of marine engine replacement parts, delivering components that meet or exceed original equipment specifications. The Sierra 18-3787 tab washer is a straightforward, cost-effective replacement to restore proper propeller security on MerCruiser Bravo III sterndrive-equipped vessels.

So far so good. we will see when package arrives....

Hands down one of the best websites to order from! Their customer service was awesome and the shipping was very fast!

So far so good

Shipping seems a bit high.

Fast and easy

very simple and saved a bunch

Quick and efficient

Great overall experience with competitive pricing

Very easy so far thanks.

You seem to have the best price and your pictures help a lot. HOWEVER -- no place did my order say &quot;Mercury Grand Marquis 2003 *Passenger Side* Glass -- and that has me concerned because I have to go by make/model/yr and then picture alone!

Uhh if I get what I ordered I'll be happy

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