Starter Solenoid – Fits Yamaha & Mercury Outboard Engines 20–90 HP
This 12-volt starter solenoid is engineered to replace failed or worn relays on a wide range of Yamaha and Mercury Marine outboard engines from 20 HP to 90 HP. Designed with an isolated base and four terminals (two 1/4"-20 and two 8-32), it ensures reliable starting performance across multiple model years and horsepower ratings.
Direct replacement for: Yamaha 65W-81941-00-00; Mercury Marine 89-818997A1, 89-818997A2, 89-818997T1, 89-818998A1, 89-818998A2, 89-850187A1, 89-850187T1.
- Four-terminal configuration for straightforward installation
- Isolated base prevents unwanted grounding
- Compatible with both Yamaha and Mercury Marine outboards
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
| Brand |
Part Number |
| Yamaha |
65W-81941-00-00 |
| Mercury Marine |
89-818997A1 |
| Mercury Marine |
89-818997A2 |
| Mercury Marine |
89-818997T1 |
| Mercury Marine |
89-818998A1 |
| Mercury Marine |
89-818998A2 |
| Mercury Marine |
89-850187A1 |
| Mercury Marine |
89-850187T1 |
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.
For Yamaha owners, here's a guide to help you identify your engine's serial/model: Yamaha Serial Number Guide. You can also review exploded diagrams to verify part numbers: Yamaha Parts Diagrams & Catalog.
| Brand |
Model |
Rated HP |
Years |
| Mercury Marine |
Outboard |
20 HP |
1987–2003 |
| Mercury Marine |
Outboard |
25 HP |
1990–2005 |
| Mercury Marine |
Outboard |
40 HP |
1989–1998 |
| Mercury Marine |
Outboard |
45 HP |
1995 |
| Mercury Marine |
Outboard |
50 HP |
1990–2003 |
| Mercury Marine |
Outboard |
55 HP |
1996–1997 |
| Mercury Marine |
Outboard |
60 HP |
1991–1998 |
| Mercury Marine |
Outboard |
65 HP |
1990–1994 |
| Mercury Marine |
Outboard |
70 HP |
1998 |
| Mercury Marine |
Outboard |
75 HP |
1990–1998 |
| Mercury Marine |
Outboard |
80 HP |
1992–2000 |
| Mercury Marine |
Outboard |
90 HP |
1999–2003 |
Technical Specifications
| Specification |
Value |
| Voltage |
12 Volts |
| Number of Terminals |
4 Terminals |
| Terminal Sizes |
(2) 1/4"-20 Terminals (2) 8-32 Terminals |
| Base Type |
Isolated Base |
Package Contents
Installation Guide
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Disconnect the battery: Remove the negative cable to prevent electrical shorts during installation.
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Locate the old solenoid: It is typically mounted near the starter motor on the outboard engine.
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Label and disconnect wires: Tag each wire before removal to ensure correct reconnection.
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Remove the mounting hardware: Unscrew the bolts or screws securing the old solenoid.
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Install the new solenoid: Position it in the same orientation as the original and secure with mounting hardware.
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Reconnect all wires: Attach each wire to the correct terminal—two 1/4"-20 terminals and two 8-32 terminals.
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Double-check connections: Ensure all terminals are tight and wires are properly seated.
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Reconnect the battery: Attach the negative cable and test the starter operation.
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Test the engine: Turn the ignition key to confirm the starter engages smoothly. If the engine does not crank, recheck all connections.
Troubleshooting & FAQ
Q: How do I confirm this solenoid fits my engine?
A: Cross-reference your original part number with the numbers listed above (Yamaha 65W-81941-00-00 or any Mercury number listed). Also verify your engine model, HP, and year in the compatibility table.
Q: What are the signs that my starter solenoid has failed?
A: Common symptoms include a clicking sound when turning the key, the starter not engaging at all, or intermittent starting issues. A failed solenoid often causes the starter motor to receive no power.
Q: Can I install this solenoid myself, or do I need a mechanic?
A: If you have basic mechanical skills and can safely disconnect the battery and label wires, you can perform the installation. However, professional installation is recommended to ensure safety and optimal performance.
Q: Will this aftermarket solenoid perform as well as the OEM part?
A: Yes. This solenoid is built to OEM specifications using comparable-grade materials in an ISO9002-certified facility, ensuring reliable starting performance that matches or exceeds the original part.
Q: Is this an OEM part or an aftermarket replacement?
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?
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Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
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Fast Global Shipping: Free delivery worldwide in 5–15 days.
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Direct from Manufacturer: Competitive pricing without compromising quality.