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Sierra 18-6437 Outboard Starter Motor Counter-Clockwise Rotation Mercury Mariner 25HP 4-Stroke

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

18-6437
06/04/2036 1:44 PM
Sale Price

$183.34

In Stock (10+)

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Usually delivered within 2 days

free shipping

FREE SHIPPING

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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 18-6437 is a high-quality outboard starter motor engineered specifically for 25 horsepower 4-stroke Mercury and Mariner outboard engines with counter-clockwise rotation. This marine-grade starter is designed to withstand the harsh marine environment while providing reliable starting performance.

Key Features:

  • Counter-clockwise rotation design for proper engine operation
  • Double-sealed housing with high-quality brushes for extended service life
  • High-quality magnets and field coils deliver superior starting torque
  • Powder-coated housing provides enhanced corrosion resistance
  • Meets SAE J1171 and ISO 8846 marine ignition protection standards
  • 100% load tested for reliability

Application:

  • Fits Mercury/Mariner 25HP 4-Stroke outboard engines (Serial Number 0G760300 and up)

OEM Cross-Reference Numbers:

  • Mercury Marine 50-888151T
  • Mercury Marine 50-830308T
  • Mercury Marine 50-859169T
  • Mercury Marine 50-893886T
  • Arco 5364

Sierra is a trusted name in marine replacement parts, offering products that meet or exceed OEM specifications. This starter motor is backed by Sierra's customer satisfaction guarantee, ensuring quality and performance you can depend on for your outboard motor.

Products specifications

Compatibility

Fits 25HP 4 Stroke 0G760300 & Up. Replaces Mercury 50-888151T50-830308T50-859169T50-893886T.

Type

Starters

Quick and easy

Thanks, that was easy

Quick and easy so far

Great easy to work with

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Ordered Monday afternoon & it was here Wednesday! Can't get any better than that. Called prior to order & they were very helpful & without a long wait time either. I bookmarked them & will be sure to buy auto parts from them again. Thanks again.

After placing my order, my item was shipped out the next business day as promised. Great service and great products, what more could you ask for!!

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