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Sierra MP39780 3-Position Ignition Starter Switch 12V 15A 5/8" Shaft

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

MP39780
06/01/2036 3:44 AM
Sale Price

$23.22

In Stock (10+)

delivery box

Usually delivered within 2 days

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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 MP39780 is a heavy-duty marine ignition starter switch designed for reliable operation in harsh marine environments. This 3-position switch (Off-Ignition-Start) features a durable polyester construction that provides maximum corrosion protection and eliminates potential electrical shorts caused by moisture exposure.

Key Features:

  • 3-position operation: Off, Ignition, and Start positions for complete engine control
  • 12-volt system with 15-amp accessory rating and 30-amp solenoid capacity
  • 5/8" shaft diameter with 7/8" mounting hole requirement
  • Polyester housing construction for superior corrosion resistance in marine applications
  • Inner seal between cylinder lock and contact plate prevents moisture intrusion
  • 3 screw terminals for secure electrical connections
  • Conventional mounting design for easy installation

This switch does not include a push-to-choke feature or protective boot. The polyester construction makes it ideal for marine applications where exposure to salt water, spray, and humidity demand components that can withstand constant moisture without corroding or failing. Perfect for replacing worn ignition switches on boats, marine engines, and other watercraft electrical systems.

Products specifications

Type

Switches

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easy ordering

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Wrong size belt. Had to return

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Very detailed list of part fitment. Radiator fits and functions very well. BUT, and this may be no fault of Autoplicity, I received the radiator w/holes punched in the box and some of the cooling fins bent. It wasn't bad enough to warrant a return, thoug

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