66M-85570-00-00 Ignition Coil for Yamaha F9.9 T9.9 F15 | JLM Marine

Ignition Coil for Yamaha F9.9 T9.9 F15 Outboard Motors

This aftermarket ignition coil is designed for Yamaha 4-stroke outboard engines ranging from 9.9HP to 15HP. It provides reliable spark delivery for smooth engine performance across the F9.9, T9.9, and F15 series motors manufactured between 1998 and 2006.

This replacement ignition coil directly supersedes Yamaha OEM part numbers 66M-85570-00, 66M-85570-01, 66M-85570-02, and 66M-85570-03, as well as Sierra part number 18-23601, ensuring broad compatibility across multiple model years.

• Single ignition coil assembly for consistent spark generation
• Designed specifically for Yamaha 4-stroke outboard motors
• Direct-fit replacement for easy installation

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 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.

Technical Specifications

Package Contents

This package includes the following component:

• 1 × Ignition Coil

Installation Guide

1. Disconnect the battery and remove the engine cowling to access the ignition system. Locate the existing ignition coil mounted on the engine block.
2. Disconnect the spark plug wire from the top of the old ignition coil. Take note of the wire routing for reinstallation.
3. Disconnect the electrical connectors from the base of the ignition coil. Label connectors if necessary to ensure correct reconnection.
4. Remove the mounting bolts securing the ignition coil to the engine using the appropriate socket or wrench. Keep hardware for reuse if in good condition.
5. Carefully remove the old ignition coil from its mounting bracket. Inspect the mounting area and clean any debris or corrosion.
6. Position the new ignition coil in the mounting bracket, aligning the bolt holes. Ensure proper orientation matching the original installation.
7. Install the mounting bolts and tighten to manufacturer specifications using a torque wrench. Do not overtighten to avoid damaging the coil housing.
8. Reconnect the electrical connectors to the base of the new ignition coil, ensuring they click securely into place. Verify connections are firm.
9. Attach the spark plug wire to the top terminal of the new ignition coil. Route the wire following the original path to prevent chafing.
10. Reinstall the engine cowling and reconnect the battery. Double-check all connections before proceeding.
11. Start the engine and allow it to idle for several minutes. Listen for smooth operation and confirm there are no misfires.
12. If the engine runs smoothly without hesitation, installation is complete. If issues persist, recheck all connections and consult a marine technician.

Troubleshooting & FAQ

Q: How do I confirm this ignition coil fits my specific Yamaha engine?
A: Cross-reference your engine's model and year with the compatibility table above. You can also verify the OEM part number stamped on your existing ignition coil matches one of the listed numbers (66M-85570-00, 66M-85570-01, 66M-85570-02, 66M-85570-03, or Sierra 18-23601).

Q: What are the signs that my ignition coil needs replacement?
A: Common symptoms include difficulty starting the engine, misfiring or rough idling, loss of power under load, or the engine stalling unexpectedly. If spark testing shows weak or no spark at the plug, the ignition coil is often the culprit.

Q: How often should I replace the ignition coil?
A: Ignition coils typically last several years under normal operating conditions. Replace the coil if you experience ignition-related performance issues, or as preventive maintenance every 5-7 years or 500-700 operating hours, especially in harsh marine environments.

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?

• 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.