Solenoid Relay – Fits Mercury 40HP-250HP (Replaces 89-817109A1, 18-5834)

Product Details

This Solenoid Relay fits Mercury outboard motors from 40HP to 250HP, covering a wide range of 3-cylinder, 4-cylinder, and V6 configurations including 2-stroke, 4-stroke EFI, Optimax, DFI, and Verado models. Compatible with Force motors (40–120HP, 1996–1999) and Mercury engines with serial numbers OD082000 and newer, this relay ensures reliable electrical starting and operation across multiple engine families.

Direct replacement for Mercury 89-817109A1, 89-817109A2, 89-817109A3, and Sierra 18-5834, plus cross-references including Arco SW109, Arrowhead SMR6010, J&N 240-22131, and WAI 67-731.

• Designed for rubber-mount and fixed-mount solenoid applications
• Compatible with both carbureted and fuel-injected systems
• Fits engines with 5/16-18 starter terminals and updated terminal configurations

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Engine & Model Compatibility

Confirm your engine model/year in the table below.

Technical Specs

Application

Solenoid Relay / Starter Relay

Fits Brand

Mercury Marine, Force

Horsepower Range

40HP–250HP

Engine Configurations

3-cylinder, 4-cylinder, V6

Fuel Systems

Carbureted, EFI, DFI, Optimax

Replaces OEM

89-817109A1, 89-817109A2, 89-817109A3

Aftermarket Cross-Reference

Sierra 18-5834, Arco SW109, Arrowhead SMR6010, J&N 240-22131, WAI 67-731

Terminal Type

5/16-18 and updated configurations

Mount Type

Rubber mount and fixed mount

What's in the Box

• 1 × Solenoid Relay

Installation Notes

1. Disconnect the battery negative terminal before beginning work to prevent electrical shorts.
2. Locate the existing solenoid relay on your outboard motor and photograph wire connections for reference.
3. Label or note each wire terminal position before disconnecting them from the old relay.
4. Remove mounting hardware securing the old solenoid and carefully extract it from the engine.
5. Compare the new solenoid relay with the original unit to confirm terminal layout and mounting holes align.
6. Position the new relay in the mounting bracket and secure with factory hardware or equivalent fasteners.
7. Reconnect wiring harness terminals to the new solenoid, matching your reference notes or photo.
8. Ensure all connections are tight and corrosion-free; apply dielectric grease to terminals for moisture protection.
9. Reconnect the battery negative terminal and test engine start function.
10. Listen for a solid click from the solenoid when the key is turned; verify the starter engages smoothly.
11. Check for any loose wires, unusual heat, or abnormal sounds during initial operation.
12. Confirm all electrical connections remain secure after the first test run.

Troubleshooting & FAQ

How do I know if my solenoid relay is failing?

Common symptoms include a clicking sound when turning the key but the engine doesn't crank, intermittent starting issues, or no response at all when attempting to start. Electrical burning smell or visible corrosion on terminals also indicate relay failure.

Will this fit engines with rubber-mount solenoids?

Yes, this relay is compatible with both rubber-mount and fixed-mount solenoid configurations, specifically covering Mercury engines with serial numbers OD082000–OG303045 that use rubber mounts, as well as newer fixed-mount designs.

What's the difference between 89-817109A1, A2, and A3?

These are sequential OEM revisions. The A2 supersedes A1, and A3 is the latest Mercury update. All three part numbers are functionally interchangeable and this aftermarket relay replaces all versions.

Can I use this on a Force outboard from the 1990s?

Yes, this relay fits Force 40, 50, 75, 90, and 120HP models from 1996–1999 with serial numbers E138600 and newer. Confirm your engine serial number against the compatibility table before ordering.

Do I need to replace any wiring when installing this relay?

In most cases, no. The relay uses the existing wiring harness and terminals. However, inspect all wire connections for corrosion, fraying, or damage, and replace any compromised wiring before installing the new solenoid.

How often should a solenoid relay be replaced?

Solenoid relays typically last several years under normal conditions. Replace when you experience starting problems, notice corrosion or heat damage, or as part of a comprehensive electrical system service. Marine environments accelerate wear due to moisture and salt exposure.

OEM vs. Aftermarket?

This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.

Shipping speed & cost

We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.

Warranty & returns

Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.

Safety & Important Info

• Verify images/specifications against your original part. If anything differs—even if your model appears compatible—do not purchase.
• This is an aftermarket replacement, not an OEM component.
• Professional installation is recommended for safety and performance.

About Sea Sierra

• Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
• Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
• Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.