Ignition Coil – Fits Yamaha 40HP Outboard Motors (Replaces 66T-85570-00)
Ignition Coil – Fits Yamaha 40HP Outboard Motors (Replaces 66T-85570-00) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
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Ignition Coil – Fits Yamaha 40HP Outboard Motors (Replaces 66T-85570-00) is backordered and will ship as soon as it is back in stock.
Product Details
This Ignition Coil – Fits Yamaha 40HP Outboard Motors (Replaces 66T-85570-00) provides a reliable spark for Yamaha 40HP 2-Stroke outboard motors manufactured between 1998 and 2017, including E40X and 40X M(W/T)HS/L models.
It serves as a direct aftermarket replacement for Yamaha OEM part number 66T-85570-00, ensuring proper fit and function.
- Engineered for direct, hassle-free installation.
- Provides high reliability and stable ignition performance.
- This package includes a matched set of two ignition coils.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yamaha | 66T-85570-00 |
Engine & Model Compatibility
Confirm your engine model and year in the table below to ensure compatibility.
For Yamaha owners: Please verify your engine's model and year range against this list to ensure proper fitment.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | 40HP | 40 | 2-Stroke | 1998–2013 | 66T-85570-00 | |
| Yamaha | 40X M(W/T)HS/L | 40 | 2-Stroke | 1998–2013 | 66T-85570-00 | |
| Yamaha | E40X M(W/T)HS/L | 40 | 2-Stroke | 1999–2009 | 66T-85570-00 | |
| Yamaha | E40X MHL | 40 | 2-Stroke | 2010–2017 | 66T-85570-00 |
Technical Specs
- Product Type
- Ignition Coil
- Installation
- Direct replacement
- Fuel Type
- Gasoline
- Housing Material
- High-temperature resistant plastic
- Dimensions
- 9.0 x 9.0 x 9.0
- Performance
- High reliability, stable performance
What’s in the Box
- 2 x Ignition Coil (Replaces 66T-85570-00)
Installation Notes
- Disconnect the battery terminals to prevent electrical shorts.
- Locate the existing ignition coils on the engine block.
- Carefully disconnect the spark plug wires and the low-voltage electrical connectors from each coil.
- Unbolt and remove the old ignition coils from their mounting points.
- Mount the new ignition coils securely in the same position.
- Reconnect the electrical connectors and attach the spark plug wires to the correct terminals on the new coils.
- Reconnect the battery terminals.
- Start the engine to test for smooth operation and ensure the issue is resolved.
Troubleshooting & FAQ
How do I confirm this ignition coil fits my specific Yamaha outboard?
This ignition coil set is designed for the Yamaha 40HP 2-stroke models listed in the Engine & Model Compatibility table. The most reliable way to confirm fitment is to match your original part's number to our listed direct replacement, 66T-85570-00.
What are the signs of a faulty ignition coil?
Common symptoms of a failing ignition coil include engine misfires (especially under load), rough idling, difficulty starting the engine, decreased power and acceleration, and increased fuel consumption.
Why does this product include two coils?
The compatible Yamaha 40HP 2-stroke outboards are typically two-cylinder engines, each requiring its own ignition coil. We sell them as a pair because it is best practice to replace all coils at the same time to ensure balanced ignition performance and prevent future issues.
Can I test my old coil before replacing it?
Yes. You can test an ignition coil using a digital multimeter to measure the resistance of the primary and secondary windings. Compare your readings to the specifications in your engine's service manual. If the readings are out of range, the coil is faulty and should be replaced.
Is this an OEM part?
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.
What are the shipping options?
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
What is the warranty and return policy?
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 vs 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.
Payment & Security
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