Aftermarket Thermostat for Yamaha 60HP/70HP 2-Stroke Outboards – Replaces 6H3-12411-11-00
Aftermarket Thermostat for Yamaha 60HP/70HP 2-Stroke Outboards – Replaces 6H3-12411-11-00 is backordered and will ship as soon as it is back in stock.
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Aftermarket Thermostat for Yamaha 60HP/70HP 2-Stroke Outboards – Re...
Aftermarket Thermostat for Yamaha 60HP/70HP 2-Stroke Outboards – Replaces 6H3-12411-11-00 is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket thermostat is designed as a replacement for the Yamaha thermostat used on selected 60HP and 70HP 2-stroke outboards. It helps regulate cooling-water flow so the engine can maintain its specified operating temperature during normal operation.
The primary manufacturer reference is Yamaha 6H3-12411-11-00. Sierra 18-3622 is a related thermostat-kit reference for applications using this thermostat; this listing is for one thermostat only, not the complete Sierra kit.
- Aftermarket replacement thermostat
- For selected Yamaha 60HP and 70HP 2-stroke outboards
- Designed for marine cooling-system temperature regulation
- Rated operating temperature: 60°C (140°F)
Part Number References
Use the references below to compare the thermostat required for your engine. Always verify the complete model designation and year before ordering.
| Brand | Part Number | Reference Type | Notes |
|---|---|---|---|
| Yamaha | 6H3-12411-11-00 | Manufacturer reference | Primary replacement reference for this thermostat. |
| Sierra | 18-3622 | Aftermarket kit reference | Cataloged as a thermostat kit; this listing contains the thermostat only. |
| Yamaha | 6H3-12411-10-00 | Legacy catalog reference | Verify the required reference against the engine model and year. |
| Yamaha | 6H3-12411-01-00 | Legacy catalog reference | Verify the required reference against the engine model and year. |
| Yamaha | 6H3-12411-00-00 | Legacy catalog reference | Verify the required reference against the engine model and year. |
Engine & Model Compatibility
The available catalog information identifies this thermostat family for selected Yamaha 60HP and 70HP 2-stroke outboards. Confirm the exact model code, model year, and required thermostat reference before installation.
| Brand | Model | Rated HP | Stroke | Catalog Year(s) | Thermostat Reference |
|---|---|---|---|---|---|
| Yamaha | 60TLR | 60 | 2-Stroke | 2001–2005 | 6H3-12411-11-00 |
| Yamaha | 60TLRA, 60TLRB, 60TLRC, 60TLRD, 60TLRNC, 60TLRZ | 60 | 2-Stroke | 2001–2005 | 6H3-12411-11-00 |
| Yamaha | C60ELRU, C60TLRU, C60TLRV, C60TLRW, C60TLRX, C60TLRY, C60TLRZ | 60 | 2-Stroke | 1996–2001 | 6H3-12411-11-00 |
| Yamaha | E60MLHT, E60MLHU, E60MLHV, E60MLHW, E60MLHX, E60MLHY | 60 | 2-Stroke | 1995–2000 | 6H3-12411-11-00 |
| Yamaha | P60TLHP, P60TLHQ, P60TLHR, P60TLHS, P60TLHT, P60TLHU, P60TLHV, P60TLHW, P60TLHX | 60 | 2-Stroke | 1991–1999 | 6H3-12411-11-00 |
| Yamaha | 70TLR | 70 | 2-Stroke | 2005–2009 | 6H3-12411-11-00 |
| Yamaha | 70TLRA, 70TLRB, 70TLRC, 70TLRD, 70TLRNC, 70TLRY, 70TLRZ | 70 | 2-Stroke | 2000–2005 | 6H3-12411-11-00 |
| Yamaha | 70ETLD, 70ETLDA, 70ETLF, 70ETLG, 70ETLH, 70ETLJ, 70ETLK, 70ETLN | 70 | 2-Stroke | 1984–1990 | Verify legacy reference before ordering. |
| Yamaha | 70TLRP, 70TLRQ, 70TLRR, 70TLRS, 70TLRT, 70TLRU, 70TLRV, 70TLRW, 70TLRX | 70 | 2-Stroke | 1991–1999 | Verify legacy reference before ordering. |
Technical Specifications
- Product Type
- Engine thermostat
- Application
- Selected Yamaha 60HP and 70HP 2-stroke outboards
- Operating Temperature
- 60°C (140°F)
- Installation
- Replacement thermostat for the original cooling-system location
- Package Type
- Single thermostat
What’s in the Box
- 1 x Thermostat
A gasket, seal, or other installation hardware is not identified as included with this single-thermostat listing. Use a new compatible gasket or seal when required by the engine service procedure.
Installation Notes
- Turn the engine off, allow it to cool completely, and follow the safety instructions in the engine service manual.
- Disconnect the battery if required by the manufacturer's service procedure.
- Locate the thermostat housing and place a suitable drain pan below the work area.
- Remove the housing fasteners and cover carefully. Keep fasteners in their original positions.
- Remove the old thermostat and clean the mating surfaces without damaging the housing.
- Install the replacement thermostat in the same orientation as the original part and fit a new compatible gasket or seal where required.
- Reinstall the housing cover and tighten the fasteners to the manufacturer's specified torque.
- Operate the outboard using the correct water-supply procedure for the model. Check for leaks and confirm normal cooling-water flow.
- Monitor engine temperature during the first run and stop the engine if overheating or abnormal temperature behavior occurs.
Troubleshooting & FAQ
What are common signs of a failing thermostat?
Symptoms may include overheating, slow warm-up, abnormal temperature behavior, or inconsistent cooling-water flow. Inspect the complete cooling system before replacing the thermostat.
What temperature is this thermostat rated for?
The catalog reference for this thermostat kit identifies a 60°C (140°F) thermostat. Confirm the required temperature rating for your exact engine before installation.
Is this a complete thermostat kit?
No. This listing is for one thermostat. Sierra 18-3622 is identified in the catalog as a thermostat-kit reference, but the kit contents are not included in this listing.
Is a gasket included?
No gasket or seal is identified as included with this single thermostat. Use the gasket or seal specified for your engine.
Will it fit an engine that is not listed?
Do not rely on appearance alone. Confirm the exact engine model, year, stroke, and required thermostat reference before purchasing or installing the part.
Is this an OEM component?
This is an aftermarket replacement, not a Yamaha-branded OEM component. Yamaha and Sierra names and part numbers are used only to identify application and reference compatibility.
Safety & Important Information
- Verify the engine model, year, stroke, and original thermostat reference before ordering.
- Do not install a thermostat with a different temperature rating unless the engine manufacturer specifies it.
- Work only on a cool engine and follow the applicable service-manual procedures.
- Professional installation is recommended when the cooling system or thermostat housing is damaged, corroded, or difficult to service.
About Sea Sierra
- Marine Replacement Parts — We provide aftermarket components for common marine service and repair applications.
- Application-Focused Information — Use model, year, stroke, and part-number details to verify fitment before purchase.
- Service Support — Check the product details and your engine service information before installation.
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