Thermostat Housing Gasket – Fits Yamaha 60-70HP (Replaces 6H3-12414-A1-00)
Thermostat Housing Gasket – Fits Yamaha 60-70HP (Replaces 6H3-12414-A1-00) is backordered and will ship as soon as it is back in stock.
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Thermostat Housing Gasket – Fits Yamaha 60-70HP (Replaces 6H3-12414...
Product Details
This is a replacement Thermostat Housing Gasket – Fits Yamaha 60-70HP outboards. It is designed to create a reliable seal between the thermostat housing and the cylinder head on specific Yamaha 2-stroke outboard engines ranging from 60 to 70 HP, manufactured between 1984 and 2009.
It directly replaces Yamaha OEM part numbers 6H3-12414-A1-00, 6H3-12414-00-00, 62Y-12414-00-00, 62Y-12414-01-00, and 65W-12414-00-00, and fits like Sierra aftermarket part 18-99124.
- Engineered from high-quality paper material to ensure a durable, leak-free seal.
- Critical for preventing coolant leaks and maintaining proper engine operating temperature.
- This single-use gasket should be replaced whenever the thermostat cover is removed for service.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Notes |
|---|---|---|
| Yamaha | 6H3-12414-A1-00 | Current Part |
| Yamaha | 6H3-12414-00-00 | Superseded by 6H3-12414-A1-00 |
| Yamaha | 62Y-12414-00-00 | Interchangeable |
| Yamaha | 62Y-12414-01-00 | Interchangeable |
| Yamaha | 65W-12414-00-00 | Interchangeable |
| Sierra | 18-99124 | Aftermarket equivalent |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
The following table lists known compatible Yamaha outboard models. It is essential to verify your specific engine model and year for an exact match.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | 70ETLJ | 70 | 2-Stroke | 1986 | 6H3-12414-A1-00 | Crankcase - Cylinder |
| Yamaha | 70ETLF | 70 | 2-Stroke | 1989 | 6H3-12414-A1-00 | Crankcase - Cylinder |
| Yamaha | 70ETLG | 70 | 2-Stroke | 1988 | 6H3-12414-A1-00 | Crankcase - Cylinder |
| Yamaha | 70ETLH | 70 | 2-Stroke | 1987 | 6H3-12414-A1-00 | Crankcase - Cylinder |
| Yamaha | E60MLHX | 60 | 2-Stroke | 1999 | 6H3-12414-A1-00 | Cylinder Crankcase |
| Yamaha | C70TLRZ | 70 | 2-Stroke | 2001 | 6H3-12414-A1-00 | Cylinder Crankcase |
| Yamaha | 70TLRNC | 70 | 2-Stroke | 2004 | 6H3-12414-A1-00 | Cylinder Crankcase |
| Yamaha | 70TLRC | 70 | 2-Stroke | 2004 | 6H3-12414-A1-00 | Cylinder Crankcase |
| Yamaha | E60MLHV | 60 | 2-Stroke | 1997 | 6H3-12414-A1-00 | Cylinder Crankcase |
| Yamaha | 70ETLDA | 70 | 2-Stroke | 1990 | 6H3-12414-A1-00 | Cylinder Crankcase |
| Yamaha | 70TLR | 70 | 2-Stroke | 2009 | 6H3-12414-A1-00 | Cylinder Crankcase |
| Yamaha | 60TLR | 60 | 2-Stroke | 2005 | 6H3-12414-A1-00 | Cylinder Crankcase |
| Yamaha | 70ETLN | 70 | 2-Stroke | 1984 | 6H3-12414-A1-00 | Cylinder Crankcase |
| Yamaha | E60MLHY | 60 | 2-Stroke | 2000 | 6H3-12414-A1-00 | Cylinder Crankcase |
| Yamaha | C60TLRY | 60 | 2-Stroke | 2000 | 6H3-12414-A1-00 | Cylinder Crankcase |
| Yamaha | 70TLRD | 70 | 2-Stroke | 2005 | 6H3-12414-A1-00 | Cylinder Crankcase |
| Yamaha | C60TLRX | 60 | 2-Stroke | 1999 | 6H3-12414-A1-00 | Cylinder Crankcase |
| Yamaha | E60MLHU | 60 | 2-Stroke | 1996 | 6H3-12414-A1-00 | Cylinder Crankcase |
| Yamaha | 70TLR | 70 | 2-Stroke | 2005 | 6H3-12414-A1-00 | Cylinder Crankcase |
| Yamaha | 60TLRA | 60 | 2-Stroke | 2002 | 6H3-12414-A1-00 | Cylinder Crankcase |
| Yamaha | 60TLRD | 60 | 2-Stroke | 2005 | 6H3-12414-A1-00 | Cylinder Crankcase |
| Yamaha | 60TLRZ | 60 | 2-Stroke | 2001 | 6H3-12414-A1-00 | Cylinder Crankcase |
Technical Specs
- Product Type
- Thermostat Housing Gasket
- Material
- Paper
- Condition
- New
- Dimensions
- 6.0 in x 7.25 in x 0.63 in
- Weight
- 0.04 lb (0.018 kg)
- Application
- Yamaha Outboard Marine Engines
- Function
- Provides a seal for the thermostat housing to the cylinder head.
- Manufacturing Origin
- Japan
What’s in the Box
- 1 x Gasket, Cover (Replaces 6H3-12414-A1-00, 62Y-12414-00-00, 65W-12414-00-00)
Installation Notes
- Disconnect the battery and allow the engine to cool completely.
- Drain the engine coolant to a level below the thermostat housing.
- Carefully remove the bolts securing the thermostat housing cover.
- Remove the cover and the old gasket. Note the orientation of the parts.
- Thoroughly clean any old gasket material or corrosion from both mating surfaces.
- Position the new gasket correctly on the cylinder head or housing.
- Reinstall the housing cover and tighten the bolts in a crisscross pattern to the manufacturer's specified torque.
- Refill the cooling system, then start the engine and check for any leaks around the housing.
Troubleshooting & FAQ
How do I know if this gasket will fit my Yamaha engine?
This gasket is designed for specific Yamaha 60-70 HP 2-Stroke models from 1984–2009. The best way to confirm fitment is to check your engine's model and year against the compatibility table on this page. For 100% certainty, cross-reference the OEM part number (6H3-12414-A1-00) with the number listed in your engine's service manual.
What are the signs of a failing thermostat housing gasket?
Common symptoms include visible coolant leaks or dried coolant residue around the thermostat housing, engine overheating alarms, or an abnormally fluctuating temperature gauge. A physical inspection may reveal a brittle, cracked, or compressed gasket that is no longer sealing properly.
Can I reuse my old gasket?
No. This is a single-use gasket. It is designed to crush and create a seal when the housing is torqued down. Once compressed, it will not provide a reliable seal if reused, leading to potential coolant leaks and overheating issues.
What’s the difference between OEM and this aftermarket 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.
How fast do you ship and what does it cost?
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.
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