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CDI Unit for Yamaha 9.9HP 15HP 2-Stroke Outboard | 6B4-85540-00
CDI Unit for Yamaha 9.9HP 15HP 2-Stroke Outboard | 6B4-85540-00
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Product Overview
Replacement 8-wire CDI ignition unit for compatible Yamaha 9.9HP and 15HP 2-stroke outboard engines.
Designed to replace Yamaha OEM 6B4-85540-00, this CDI module is intended for compatible marine ignition systems using the same wiring, connector configuration, mounting dimensions, and original CDI design.
The unit measures approximately 77 × 59 × 21mm with an approximately 77mm mounting-hole distance.
Before ordering, verify the OEM number, engine model, 8-wire configuration, connectors, mounting dimensions, and original CDI appearance.
Product Compatibility
| Make | Engine | Engine Type | Fitment Notes | OEM Reference |
|---|---|---|---|---|
| Yamaha | 9.9HP | 2-Stroke Outboard | Selected compatible models | 6B4-85540-00 |
| Yamaha | 15HP | 2-Stroke Outboard | Selected compatible models | 6B4-85540-00 |
Important: This CDI should not be selected by horsepower alone. Yamaha used different ignition modules across 9.9HP and 15HP outboard engine families.
Match OEM 6B4-85540-00 and compare the original CDI before ordering.
OEM Cross-Reference Numbers
Yamaha
- 6B4-85540-00
- 6B4-85540-00-00
The extended -00-00 format may appear in Yamaha parts catalogs or dealer listings for the same base part reference.
Specifications
| Specification | Details |
|---|---|
| Product Type | CDI Unit / Ignition Module |
| OEM Reference | 6B4-85540-00 |
| Engine Type | 2-Stroke Outboard |
| Listed Horsepower | 9.9HP / 15HP |
| Wiring | 8-Wire |
| Length | 77 mm / 3.03 in |
| Width | 59 mm / 2.32 in |
| Height | 21 mm / 0.83 in |
| Mounting Hole Diameter | 13 mm / 0.51 in |
| Mounting Hole Distance | 77 mm / 3.03 in |
| Housing Material | ABS |
| Application | Yamaha Outboard Motor |
| Condition | New |
| Package Quantity | 1 CDI Unit |
Key Features
- 8-Wire CDI Configuration: Designed for compatible Yamaha 2-stroke outboard ignition systems.
- OEM-Specific Replacement: Replaces Yamaha 6B4-85540-00.
- 9.9HP / 15HP Application: Intended for selected compatible Yamaha outboard engines.
- Marine Ignition Component: ABS housing provides protection for the internal electronic components.
- Fitment Reference Dimensions: 77 × 59 × 21mm housing and approximately 77mm mounting-hole spacing help confirm compatibility.
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Fitment FAQ
Will this part fit my specific model and year?
This CDI is intended for selected Yamaha 9.9HP and 15HP 2-stroke outboard engines using OEM 6B4-85540-00.
Because horsepower alone does not identify the ignition system, verify your complete engine model and original CDI before ordering.
Do I need to match the OEM part number?
Yes. Matching the OEM number is strongly recommended.
Primary references:
6B4-85540-00 / 6B4-85540-00-00
The OEM number provides a much more reliable fitment reference than simply matching a 9.9HP or 15HP engine.
What models or situations does this part not fit?
Do not assume compatibility with:
Every Yamaha 9.9HP outboard
Every Yamaha 15HP outboard
4-stroke engines
CDI units using a different OEM number
7-wire CDI systems
Modules with different connectors
Applications with different mounting dimensions or wiring
In particular, this 8-wire 6B4-85540-00 CDI should not be confused with the 7-wire 63V-85540-00 CDI used on other Yamaha 9.9HP / 15HP 2-stroke applications.
What should I check before ordering?
Confirm:
Yamaha outboard engine model
Engine type
2-stroke configuration
OEM 6B4-85540-00
8-wire configuration
Connector shapes and terminal arrangement
Approx. 77 × 59 × 21mm module dimensions
Approx. 77mm mounting-hole distance
Original CDI appearance