Manifold Gasket – Fits Yamaha 6HP & 8HP Outboards (Replaces 6G1-13645-A1-00)
Manifold Gasket – Fits Yamaha 6HP & 8HP Outboards (Replaces 6G1-13645-A1-00) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Manifold Gasket – Fits Yamaha 6HP & 8HP Outboards (Replaces 6G1...
Product Details
This Manifold Gasket provides a reliable seal for the front reed intake on Yamaha 6HP and 8HP 2-stroke outboard engines manufactured between 1984 and 1991. It is designed as a direct-fit replacement, ensuring proper function and preventing intake leaks for models including the 6LJ, 6SJ, 8LN, and 8SN series.
It serves as a direct interchange for Yamaha OEM part numbers 6G1-13645-A1-00 and its predecessor 6G1-13645-00-00, as well as the Sierra aftermarket equivalent 18-99110.
- Installation Method: Direct fit
- Primary Application: Front reed intake manifold
- Fuel Compatibility: Gasoline
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Superseded By | Notes |
|---|---|---|---|
| Yamaha (OEM) | 6G1-13645-A1-00 | Current active part number | |
| Yamaha (OEM) | 6G1-13645-00-00 | 6G1-13645-A1-00 | |
| Sierra (Aftermarket) | 18-99110 | Direct cross-reference |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This gasket is designed for specific Yamaha outboards. Please verify your model is listed before ordering.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. |
|---|---|---|---|---|---|
| Yamaha | 6LJ, 6SJ | 6 | 2-Stroke | 1986 | 6G1-13645-A1-00 |
| Yamaha | 6LH, 6SH | 6 | 2-Stroke | 1987 | 6G1-13645-A1-00 |
| Yamaha | 6LG, 6SG | 6 | 2-Stroke | 1988 | 6G1-13645-A1-00 |
| Yamaha | 6LF, 6SF | 6 | 2-Stroke | 1989 | 6G1-13645-A1-00 |
| Yamaha | 6LD, 6SD | 6 | 2-Stroke | 1990 | 6G1-13645-A1-00 |
| Yamaha | 6MLHP, 6MSHP | 6 | 2-Stroke | 1991 | 6G1-13645-A1-00 |
| Yamaha | 8LN, 8SN | 8 | 2-Stroke | 1984 | 6G1-13645-A1-00 |
| Yamaha | 8LK, 8SK | 8 | 2-Stroke | 1985 | 6G1-13645-A1-00 |
| Yamaha | 8LJ, 8SJ | 8 | 2-Stroke | 1986 | 6G1-13645-A1-00 |
| Yamaha | 8LH, 8SH | 8 | 2-Stroke | 1987 | 6G1-13645-A1-00 |
| Yamaha | 8LG, 8SG | 8 | 2-Stroke | 1988 | 6G1-13645-A1-00 |
| Yamaha | 8LF, 8SF | 8 | 2-Stroke | 1989 | 6G1-13645-A1-00 |
| Yamaha | 8LD, 8SD | 8 | 2-Stroke | 1990 | 6G1-13645-A1-00 |
| Yamaha | 8MLHP, 8MSHP | 8 | 2-Stroke | 1991 | 6G1-13645-A1-00 |
Technical Specs
- Product Type
- Manifold Gasket
- Installation
- Direct fit
- Fuel Type
- Gasoline
- Housing Material
- Paper/Composite material
- Dimensions
- 7.25" L x 6.0" W x 0.63" H
- Warranty
- Manufacturer standard warranty
- Other Technical Attributes
- Front reed intake manifold gasket
What’s in the Box
- 1 x Gasket, Manifold (equivalent to 6G1-13645-A1-00)
Installation Notes
- Disconnect the negative battery terminal and relieve fuel system pressure for safety.
- Carefully detach any hoses, sensors, and linkages connected to the intake manifold.
- Unbolt and remove the intake manifold from the engine block.
- Thoroughly remove the old gasket and clean all residue from both the engine and manifold mating surfaces. Use a plastic scraper to avoid gouging the metal.
- Position the new gasket, ensuring all bolt holes and intake ports are perfectly aligned.
- Reinstall the intake manifold, starting all bolts by hand before tightening them in the sequence and to the torque values specified by the manufacturer.
- Reconnect all previously removed components.
- Start the engine and carefully check for any air or fuel leaks around the manifold before operating the engine under load.
Troubleshooting & FAQ
What are the signs of a failed manifold gasket?
Common symptoms include a rough or unstable idle, engine misfires, poor acceleration, reduced fuel economy, and a hissing sound from the engine bay. These signs point to a vacuum leak caused by a compromised gasket seal.
Can this gasket be reused?
No. Intake manifold gaskets are single-use components designed to crush and create a seal. Reusing an old gasket will almost certainly result in leaks and poor engine performance.
How can I ensure this part fits my specific engine?
The most reliable method is to match your engine's model and year to the compatibility table. Additionally, visually comparing our product images to your old part before installation can help confirm fitment.
Is there a recommended replacement interval?
There is no fixed replacement interval. This gasket should be replaced whenever the intake manifold is removed for other service, or if symptoms of a leak appear.
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.
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