Thermostat Gasket – Fits Yamaha 6–9.9HP Outboards (Replaces 6G8-12414-A0-00)
Thermostat Gasket – Fits Yamaha 6–9.9HP Outboards (Replaces 6G8-12414-A0-00) 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
Thermostat Gasket – Fits Yamaha 6–9.9HP Outboards (Replaces 6G8-124...
Product Details
This Thermostat Gasket – Fits Yamaha 6–9.9HP Outboards (Replaces 6G8-12414-A0-00) is a direct-fit replacement for Yamaha 6HP, 8HP, and 9.9HP 4-Stroke outboards from 1985–2023, ensuring a reliable seal for the cooling system.
It provides a direct interchange for Yamaha OEM part numbers 6G8-12414-00-00, 6G8-12414-A0-00, 60R-E2414-A0-00, and is also equivalent to EMP 27-03305 and GLM Marine 38078.
- Engineered for a direct-fit installation.
- Seals the thermostat housing to the engine block to prevent coolant leaks.
- Constructed from high-quality composite gasket material.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yamaha | 6G8-12414-00-00 |
| Yamaha | 6G8-12414-A0-00 |
| Yamaha | 60R-E2414-A0-00 |
| EMP | 27-03305 |
| GLM Marine | 38078 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Yamaha Outboards: This part is confirmed to fit the specific models listed below. It is crucial to check your engine's model and year to ensure compatibility.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | F6MLHA | 6 | 4-Stroke | 2002 | 6G8-12414-A0-00 | |
| Yamaha | F6MLHB | 6 | 4-Stroke | 2003 | 6G8-12414-A0-00 | |
| Yamaha | F6MLHC | 6 | 4-Stroke | 2004 | 6G8-12414-A0-00 | |
| Yamaha | F6MLHZ | 6 | 4-Stroke | 2001 | 6G8-12414-A0-00 | |
| Yamaha | F6MSHA | 6 | 4-Stroke | 2002 | 6G8-12414-A0-00 | |
| Yamaha | F6M5HB | 6 | 4-Stroke | 2003 | 6G8-12414-A0-00 | |
| Yamaha | F6MSHC | 6 | 4-Stroke | 2004 | 6G8-12414-A0-00 | |
| Yamaha | F6M5HZ | 6 | 4-Stroke | 2001 | 6G8-12414-A0-00 | |
| Yamaha | F8LMHB | 8 | 4-Stroke | 2015–2021 | 6G8-12414-A0-00 | |
| Yamaha | F8MLHA | 8 | 4-Stroke | 2002 | 6G8-12414-A0-00 | |
| Yamaha | F8MLHB | 8 | 4-Stroke | 2003 | 6G8-12414-A0-00 | |
| Yamaha | F8MLHC | 8 | 4-Stroke | 2004 | 6G8-12414-A0-00 | |
| Yamaha | F8MLHZ | 8 | 4-Stroke | 2001 | 6G8-12414-A0-00 | |
| Yamaha | F8MSHA | 8 | 4-Stroke | 2002 | 6G8-12414-A0-00 | |
| Yamaha | F8MSHB | 8 | 4-Stroke | 2003 | 6G8-12414-A0-00 | |
| Yamaha | F8MSHC | 8 | 4-Stroke | 2004 | 6G8-12414-A0-00 | |
| Yamaha | F8MSHZ | 8 | 4-Stroke | 2001 | 6G8-12414-A0-00 | |
| Yamaha | F8SMHB | 8 | 4-Stroke | 2015–2021 | 6G8-12414-A0-00 | |
| Yamaha | F9.9 | 9.9 | 4-Stroke | 1985–2023 | 6G8-12414-A0-00 | Various models including F9.9MLHA, F9.9MLHB, F9.9MLHC, etc. |
| Yamaha | T8ELHA | 8 | 4-Stroke | 2002 | 6G8-12414-A0-00 | |
| Yamaha | T8ELHB | 8 | 4-Stroke | 2003 | 6G8-12414-A0-00 | |
| Yamaha | T8ELHC | 8 | 4-Stroke | 2004 | 6G8-12414-A0-00 | |
| Yamaha | T8EXHA | 8 | 4-Stroke | 2002 | 6G8-12414-A0-00 | |
| Yamaha | T8EXHB | 8 | 4-Stroke | 2003 | 6G8-12414-A0-00 | |
| Yamaha | T8EXHC | 8 | 4-Stroke | 2004 | 6G8-12414-A0-00 | |
| Yamaha | T8PLHA | 8 | 4-Stroke | 2002 | 6G8-12414-A0-00 | |
| Yamaha | T8PLHB | 8 | 4-Stroke | 2003 | 6G8-12414-A0-00 | |
| Yamaha | T8PLHC | 8 | 4-Stroke | 2004 | 6G8-12414-A0-00 | |
| Yamaha | T8PLHZ | 8 | 4-Stroke | 2001 | 6G8-12414-A0-00 | |
| Yamaha | T8PLRA | 8 | 4-Stroke | 2002 | 6G8-12414-A0-00 | |
| Yamaha | T8PLRB | 8 | 4-Stroke | 2003 | 6G8-12414-A0-00 | |
| Yamaha | T8PLRC | 8 | 4-Stroke | 2004 | 6G8-12414-A0-00 | |
| Yamaha | T8PLRZ | 8 | 4-Stroke | 2001 | 6G8-12414-A0-00 | |
| Yamaha | T8PXHA | 8 | 4-Stroke | 2002 | 6G8-12414-A0-00 | |
| Yamaha | T8PXHB | 8 | 4-Stroke | 2003 | 6G8-12414-A0-00 | |
| Yamaha | T8PXHC | 8 | 4-Stroke | 2004 | 6G8-12414-A0-00 | |
| Yamaha | T8PXHZ | 8 | 4-Stroke | 2001 | 6G8-12414-A0-00 | |
| Yamaha | T8PXRA | 8 | 4-Stroke | 2002 | 6G8-12414-A0-00 | |
| Yamaha | T8PXRB | 8 | 4-Stroke | 2003 | 6G8-12414-A0-00 | |
| Yamaha | T8PXRC | 8 | 4-Stroke | 2004 | 6G8-12414-A0-00 | |
| Yamaha | T8PXRZ | 8 | 4-Stroke | 2001 | 6G8-12414-A0-00 | |
| Yamaha | T9.9 | 9.9 | 4-Stroke | 1985–2023 | 6G8-12414-A0-00 | Various models including T9.9ELH, T9.9ELHA, T9.9ELHB, etc. |
| Yamaha | FT9.9 | 9.9 | 4-Stroke | 1985–1990 | 6G8-12414-A0-00 | Various models including FT9.9ELD, FT9.9ELF, FT9.9ELG, etc. |
Technical Specs
- Product Type
- Thermostat Cover Gasket
- Installation
- Direct fit
- Housing Material
- Gasket material (paper/composite)
- Dimensions
- 11.0" L x 7.0" W x 0.5" H
- Warranty
- Manufacturer standard warranty
- Other Technical Attributes
- Seals thermostat housing to engine block
What’s in the Box
- 1 x Thermostat Gasket (6G8-12414-A0-00)
Installation Notes
- Ensure the engine is completely cool and disconnect the battery for safety.
- Locate the thermostat housing and place a container underneath to catch any residual coolant.
- Carefully remove the bolts securing the housing cover. Note their positions if they are different lengths.
- Gently pry the cover off. Remove the old thermostat and gasket.
- Thoroughly clean both mating surfaces on the engine block and the housing cover. All old gasket material must be removed for a proper seal.
- Place the new gasket in position on the housing.
- Reinstall the housing cover and tighten the bolts in a crisscross pattern to the manufacturer-specified torque. Do not over-tighten.
- Refill the cooling system, then start the engine and carefully check for any leaks around the housing.
Troubleshooting & FAQ
How do I know if my thermostat gasket needs replacing?
Common signs of a failing gasket include visible coolant leaks around the thermostat housing, engine overheating alerts, or discovering cracks and brittleness during a visual inspection.
Will this fit all Yamaha 9.9HP engines?
This gasket fits a very wide range of Yamaha F9.9 and T9.9 4-stroke models from 1985 to 2023. However, due to the large number of sub-models, it is essential to check your specific engine model against our compatibility table or contact us with your engine's full model number to confirm fitment before ordering.
What is the main cause of thermostat gasket failure?
Gaskets can degrade over time due to constant heat cycles and exposure to coolant chemicals. Improper installation, such as uneven bolt torque or unclean mating surfaces, can also cause premature failure.
Can I reuse my old gasket?
No. Thermostat gaskets are single-use components designed to crush and seal. Once removed, they will not provide a reliable seal and must be replaced.
Is this an OEM part?
This is an aftermarket replacement part, not an original equipment manufacturer (OEM) component. It has been engineered to meet or exceed OEM specifications for fit, form, and function.
What if I can't find my exact model in the compatibility list?
If your model is not listed, please do not assume compatibility. Contact our support team with your engine's full model and serial number, and we will help you verify the correct part.
What is the difference between OEM and aftermarket parts?
This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials and manufactured in an ISO 9002 facility, with batch inspections for consistency.
How fast is shipping?
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free, and expedited options will appear at checkout if available for your location.
What is the warranty and return policy?
This part is covered by a 1-year warranty against manufacturing defects under normal use. If an issue arises, contact our support with your order details. Returns are accepted within our standard window for unused items in their original condition. Please see our full policy page or reach out for instructions.
Safety & Important Info
- Verify images and specifications against 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 quality control.
Payment & Security
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