My Account
Shopping Cart

Sierra 18-5605 Outboard Starter for Mercury & Mariner 40-50 HP

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

18-5605
07/13/2036 6:09 AM
Sale Price

$215.78

In Stock (10+)

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 18-5605 is a replacement electric starter for Mercury and Mariner outboard engines. Designed as a direct drop-in replacement for OEM Mercury part numbers 50-73521, 50-73521T, and 50-898265005, this starter delivers reliable cranking performance for 40–50 HP, 4-cylinder outboard applications.

Sierra's 18-56 series starters incorporate several design improvements over standard starters to maximize longevity and ease of installation in demanding marine environments.

Key Features:

  • Enhanced Connectivity: Superior connection between the solenoid and commutator brushes for consistent starting
  • Improved Durability: Updated planetary gear and clutch gear spring to maximize lifespan and reliability
  • Optimized Performance: Updated solenoid design utilizing higher quality materials
  • Easier Installation: Increased battery terminal length for simpler setup
  • Water Resistance: Strategically integrated seals to reduce water intrusion
  • 10-Tooth Drive Gear — 12V, counter-clockwise (CCW) rotation

OEM Cross-Reference:

  • Mercury Marine: 50-73521, 50-73521T, 50-898265005
  • Arco: 5379
  • Mallory: 9-15025

Sierra is the market leader in aftermarket marine engine parts, offering a comprehensive product line backed by an unsurpassed customer satisfaction warranty covering parts and labor.

great company to buy from. called them up to find an AFR gauge set. while the one i had my eye one was no longer available, they worked with me to find another one that fit my application and visual requirements. thanks autoplicity!

Easy and quick!

Good prices. Fast shipping. Fit my 2011 Dodge 3500 Mega Cab Dually perfect. Thanks.

I was asked if the product I was purchasing was needed by a specific date in order to complete a project on time. Autoplicity responded and had the product to me a day earlier than I asked for without additional cost to me. I will order from them again.

easy to find item I wanted and at a good price.

My order for a "Thule" bike rack went thru like silk. Was received (1) day early. Would recommend "Autoplicity" to anyone. Best buy I could find on line.<br><br>Customer in Kokomo, IN

it was quick and easy

QUICK AND EASY

Really wish I wouldn't had paid for two day shipping. It was a totally waste of $25.

Great Price -- Better Than AMAZON ! Great Delivery -- Great email with status of order etc.

Simple and fast checkout

Very cheap place to get name brand parts! Fast shipping!

Best prices of any other online auto parts merchant.<br><br>Communication of the order status and was very prompt and accurate and professional.<br><br>I wouldnt hesitate to do business again with autoplicity -- my go to site next time I need auto parts!

Very quick on shipping, at a great 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