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 designed for Mercury and Mariner DFI, EFI, and MPI outboard motors that use a 6-wire connection. It features a durable, anti-corrosion polyester housing and brass contacts for reliable performance in marine environments.

It serves as a direct replacement for multiple Mercury and Sierra part numbers, ensuring broad compatibility with applicable outboard engines.

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

Part Number Cross-Reference

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

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.

Technical Specifications

Package Contents

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

Explosion Diagram

Installation Guide

1. Safety First: Disconnect the boat's battery cables to prevent electrical shorts.
2. Access Panel: Gain access to the rear of the dashboard or control panel where the switch is mounted.
3. Label Wires: Before disconnecting, carefully label each wire with tape to ensure correct reassembly.
4. Disconnect Old Switch: Unplug the wire harness connector or individual wires from the old ignition switch.
5. Remove Old Switch: Unscrew the outer retaining nut and remove the old switch from the panel.
6. Install New Switch: Insert the new ignition switch into the panel and tighten the retaining nut to secure it.
7. Reconnect Wires: Attach the wiring connector to the new switch, ensuring it is fully seated.
8. Test System: Reconnect the battery, and test all key positions (OFF, RUN, START) to confirm proper function before starting the engine.

Troubleshooting & FAQ

How do I confirm this switch fits my Mercury engine?
Check that your engine is a DFI, EFI, or MPI model and falls within the serial number ranges 0N001590 and higher or 0G575500 and higher. Always cross-reference the OEM part number (87-17009A5) with your engine's service manual or parts diagram.

What are common signs of a failing ignition switch?
Symptoms include the key feeling loose or difficult to turn, intermittent power loss to gauges or accessories, the engine failing to crank, or the starter continuing to run after the key is released from the START position.

Is this a "push-to-choke" ignition switch?
No, this is a standard 3-position switch (OFF-RUN-START). It does not have an integrated push-to-choke function. Ensure your system does not require this feature before purchasing.

OEM vs. Aftermarket?
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.

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

What is your warranty and return policy?
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.