SKU: 99137878108

Ignition Key Switch – Fits Mercury/Mariner DFI, EFI & MPI Outboard Motors (Replaces 87-17009A5)

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Description

Ignition Key Switch – Fits Mercury/Mariner DFI, EFI & MPI Outboard Motors (Replaces 87-17009A5)Ignition Key Switch Fits Mercury Mariner DFI, EFI & MPI Outboard Motors (Replaces 87 17009A5) This panel mounted ignition key switch is a reliable replacement for Mercury and Mariner outboard motor control boxes requiring a 6 wire connection. It is designed for compatibility with a range of DFI (Direct Fuel Injection), EFI (Electronic Fuel Injection), and MPI (Multi Point Injection) engines. This unit is a direct replacement for Mercury part numbers

Ignition Key Switch – Fits Mercury/Mariner DFI, EFI & MPI Outboard Motors (Replaces 87-17009A5)

This panel-mounted ignition key switch is a reliable replacement for Mercury and Mariner outboard motor control boxes requiring a 6-wire connection. It is designed for compatibility with a range of DFI (Direct Fuel Injection), EFI (Electronic Fuel Injection), and MPI (Multi-Point Injection) engines.

This unit is a direct replacement for Mercury part numbers 87-17009A5 and 87-17009A2, as well as Sierra part numbers MP41070-2, MP41070-1, and MP41070.

  • Installation Type: Panel Mount
  • Connection: 6-Wire
  • Package Includes: 1x Ignition Key Switch, 2x Keys

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Brand Part Number
Mercury 87-17009A5
Mercury 87-17009A2
Sierra MP41070-2
Sierra MP41070-1
Sierra MP41070

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Brand Model Rated HP Stroke OEM Part No. Notes
Mercury/Mariner DFI EFI MPI Outboard Motors Various Various 87-17009A5 Suits serial range: 0N001590+, 0G575500+

Technical Specifications

Specification Value
Product Type Ignition Key Switch
Installation Panel Mount
Fuel Type Gasoline
Connection 6-Wire
Housing Material Polyester Anti-Corrosion Housing with Brass Contacts
Dimensions 57 × 37 mm (2.3 × 1.5 in)
Weight 117g (4.1 oz) approximate
Mounting Hole 7/8" Thread Size
Operating Voltage 12V DC
Current Rating Ignition: 15 Amp @ 12V DC
Solenoid: 30 Amp @ 12V DC
Choke: 7 Amp @ 12V DC
Switch Positions 3-Position (OFF - RUN - START)
For Panels Up To 15.87 mm (5/8") thickness
Other Technical Attributes Has return spring for 3 positions

Package Contents

  • 1 × Ignition Key Switch (87-17009A5)
  • 2 × Ignition Keys

Installation Guide

  1. Safety First: Disconnect the boat's battery cables (negative first, then positive) to prevent electrical shorts.
  2. Access the Switch: Open or remove the control box panel to access the back of the old ignition switch.
  3. Label and Disconnect: Before disconnecting, label each wire to ensure correct placement on the new switch. Carefully unplug the 6-wire connector.
  4. Remove Old Switch: Unscrew the mounting nut on the front of the panel and remove the old ignition switch.
  5. Install New Switch: Insert the new ignition switch into the panel, orient it correctly, and tighten the mounting nut until snug. Do not overtighten.
  6. Reconnect Wires: Attach the 6-wire connector to the new switch, ensuring it is fully seated and secure.
  7. Test the System: Reconnect the battery (positive first, then negative) and test all switch positions (OFF, RUN, START) to confirm proper function before heading out on the water.

Troubleshooting & FAQ

Q: How do I confirm this ignition switch fits my specific Mercury engine?

A: This switch fits various Mercury/Mariner DFI, EFI, and MPI outboard motors. The best way to confirm is to match your existing part number to the ones listed in our cross-reference table (87-17009A5, 87-17009A2) or the Sierra equivalents. Also, ensure your system uses a 6-wire connection.

Q: What are the common signs that my ignition key switch is failing?

A: Common symptoms include difficulty turning the key, the engine not cranking or starting intermittently, the engine shutting off unexpectedly, or a loss of power to accessories when the key is in the 'RUN' position. Corrosion on the contacts can also be a visual indicator.

Q: Is this a direct replacement for the Sierra MP41070-2?

A: Yes, this ignition switch serves as a direct aftermarket replacement for Sierra part numbers MP41070-2, MP41070-1, and MP41070, along with the OEM Mercury numbers.

Q: OEM vs. Aftermarket?

A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

Q: How fast do you ship and how much does it cost?

A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

Q: What is your warranty and return policy?

A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

  • Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
  • This product is an aftermarket replacement part and is not an OEM component.
  • Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

  • Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
  • Fast Global Shipping: Free delivery worldwide in 5–15 days.
  • Direct from Manufacturer: Competitive pricing without compromising quality.
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 99137878108

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