Needle Valve Assembly – Fits Yamaha 40HP Outboard Engines (Replaces 6F5-14390-21)
Needle Valve Assembly – Fits Yamaha 40HP Outboard Engines (Replaces 6F5-14390-21) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Product Details
This Needle Valve Assembly – Fits Yamaha 40HP Outboard Engines (Replaces 6F5-14390-21) is designed for consistent fuel regulation in Yamaha 2-Stroke 40HP outboard engines, including the E40G, E40J, K40, and 40J series. As a critical component of the carburetor, it ensures reliable engine performance by precisely managing fuel flow.
It serves as a direct interchange for Yamaha OEM part numbers 6F5-14390-21, 6F5-14390-21-00, 6F5-14390-20, and 6F5-14390-12, offering a seamless fit and function.
- Installs directly into the carburetor without modification.
- Engineered for use in marine environments with gasoline fuel systems.
- Includes the complete needle valve assembly for a full replacement.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yamaha | 6F5-14390-21 |
| Yamaha | 6F5-14390-21-00 |
| Yamaha | 6F5-14390-20 |
| Yamaha | 6F5-14390-12 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This component is verified to fit the following Yamaha outboard models.
| Brand | Model | Rated HP | Stroke | OEM Part No. |
|---|---|---|---|---|
| Yamaha | E40G | 40 | 2-Stroke | 6F5-14390-21 |
| Yamaha | E40J | 40 | 2-Stroke | 6F5-14390-21 |
| Yamaha | K40 | 40 | 2-Stroke | 6F5-14390-21 |
| Yamaha | 40J | 40 | 2-Stroke | 6F5-14390-21 |
Technical Specs
- Product Type
- Carburetor Needle Valve Assembly
- Installation
- Direct replacement
- Fuel Type
- Gasoline
- Connection
- Direct mount to carburetor
- Housing Material
- Metal (brass)
- Housing Color
- Silver/brass
- Dimensions
- 9.0 × 7.0 × 1.0 in
- Weight
- 10g (0.35 oz)
- Fitting Type
- Direct fit
- Other Technical Attributes
- Critical component of fuel regulation system
What’s in the Box
- 1 x Needle Valve Assembly (6F5-14390-21)
Installation Notes
- Shut off the fuel supply and disconnect the engine's battery.
- Carefully remove the carburetor assembly from the engine.
- Disassemble the float bowl on a clean surface to access the old needle valve and float pin.
- Remove the old needle valve assembly. Clean the valve seat area of any debris.
- Install the new needle valve, ensuring it is seated correctly and the float moves freely.
- Reassemble the carburetor float bowl and reinstall the carburetor onto the engine.
- Reconnect the fuel line and battery, check for leaks, and test engine operation.
Troubleshooting & FAQ
How do I know if the needle valve needs replacing?
Common signs of a failing needle valve include fuel leaking from the carburetor, a flooded engine, rough idling, or difficulty starting. These symptoms indicate the valve is no longer seating correctly to regulate fuel flow.
Will this fit my specific engine serial number?
This part is confirmed to fit Yamaha 40HP models E40G, E40J, K40, and 40J. Because precise serial number compatibility data is not available, we strongly recommend verifying your required part number against the references in the Part Number Matrix.
What is the function of the needle valve?
The needle valve works with the carburetor's float to control the amount of fuel entering the float bowl. As the fuel level rises, the float pushing the needle into its seat, stopping the flow. This maintains the correct fuel level for consistent engine operation.
Is any adjustment needed after installation?
This is a direct-fit component and typically requires no adjustment. However, it is always best practice to check and, if necessary, adjust the carburetor float height during installation to ensure optimal fuel levels.
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 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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