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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4.6 ★★★★★
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Reviewed in the United States on June 1, 2026
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I ordered these shelves to display my figures and dolls, and I love the way they look! I ordered 2 sets of the 4 pack in black with black hardware. After looking at reviews, I took the jump and bought them and don't regret it! TL;DR: Listing is accurate, don't use the paper measurement thingy, quality is what you'd expect for the price, doesn't come pre-drilled, easy enough to put together, over all worth it if you're looking for smaller, decent quality, decent price shelves especially if you display figures or dolls. 1. Listing: They are accurate to the measurements! They're only 5.5 inches deep, so there isn't much (if at all) any room for layering. They do feel small, but the listing is accurate!! Mine are paired next to each other to create a "longer" shelf. DO NOT use the paper measurement thingy. Another review mentioned it was un-even, and after holding it to mine, yeah, it was off. I'd highly recommend a stud finder, small leveler, and a white gel pen or marker to mark where to drill if you do. 2. Assembling & Mounting: The shelves didn't come with pre-drilled holes for the mounting options because it was easy enough to screw into. I will warn you that the small screws only came with a singular extra, so be careful about losing them in case it's the same for you... I'd highly recommend doing this on a FLAT surface. I stood the shelves on the side that would be flat against the wall and set the brackets against it. I put one screw in on each side (both brackets have 1 screw to hold them where I want) then I laid it on its top and tightened and added the other screw. I may have done more work than needed, but none of mine are leaning forward or backward super far. I used the "load bearing" mount simply because I like the look but if you intend to put books, I would do the "no drop" design and possibly get some other L brackets for more support since books can get heavy. PLAN WHERE YOU WANT THE BRACKETS if you intend on doing the "load bearing" design or adding any more brackets. 4. Quality: I kind of expected the wood to be a bit thicker/more sturdy feeling, but upon realizing they didn't come pre-drilled, it made more sense. THEY CHIP AND SCRATCH EASILY. If you're like me and don't really care as long as you cant see/don't notice it, then this isn't any concern but they may come damaged cause some of our mail couriers aren't the best. If you stick them in the corner like I did, please be careful about it slipping! I accidentally dropped the second one from a 21-inch TV stand after adding brackets, and the corner chipped (yes, I measured). The hardware is standard screw quality, and the brackets could be better. After reading the broken bracket reviews plus the price, I honestly wasn't expecting much, but they aren't too bad! You can always replace them with another one you like! 5. Overall: I'd say these are worth the price and I see why "customers usually keep this item"! They were easy enough to mount, even if you aren't the handiest man out there. I'd definitely recommend these if you're looking to display anime figures or dolls like I do! They're nice for adding vertical space without sticking out of the wall too much! Definitely good for smaller spaces! I'm very happy with this product and will more than likely return to this listing if I want some decent and affordable shelving! Thank you for reading my review, Im usually hesitant to buy online so I hope it helps you decide if you wanna buy these shelves as well! (Also, in case anyone is wondering the layout, the longest shelf will be 1, the middle length will be 2, the shortest length will be 3. It's the last image of the review!)
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Reviewed in the United States on August 8, 2025
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Isabel Hernandez
Los Angeles, US
★★★★★ 5
Stylish, Sturdy and Perfect for Small Spaces
Color: A. Black Board & Black Brackets, Number Of Shelves: 4, Size: 16-inch, Color: A. Black Board & Black Brackets, Number Of Shelves: 4, Size: 16-inch
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Reviewed in the United States on May 5, 2026
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Ash Wallace
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Pirate ship shelves bathroom - perfect!
Color: C. Rustic Brown Board & Black Brackets, Number Of Shelves: 4, Size: 16-inch, Color: C. Rustic Brown Board & Black Brackets, Number Of Shelves: 4, Size: 16-inch
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Reviewed in the United States on May 23, 2026
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J23
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★★★★★ 4
Amazing little shelves
Color: G. Black Board & Gold Brackets, Number Of Shelves: 4, Size: 16-inch, Color: G. Black Board & Gold Brackets, Number Of Shelves: 4, Size: 16-inch
I love them! I use them in my nail room for clients and to hold my product. They are sturdy enough to put phones, keys, and their water bottles on. Being able to hang them in different ways is awesome for different aesthetics.4 different sizes. Easy to put together it came away with all the hardware you need. My only complaint is that the wood fills rough so not really able to dust them. I have to fix that
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