Thermostat Kit – Fits Mercury/Mariner 75-150 HP 4-Stroke EFI (Replaces 892864T06, 892864A06)
Thermostat Kit – Fits Mercury/Mariner 75-150 HP 4-Stroke EFI (Replaces 892864T06, 892864A06) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
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Thermostat Kit – Fits Mercury/Mariner 75-150 HP 4-Stroke EFI (Repla...
Thermostat Kit – Fits Mercury/Mariner 75-150 HP 4-Stroke EFI (Replaces 892864T06, 892864A06) is backordered and will ship as soon as it is back in stock.
Product Details
This complete Thermostat Kit – Fits Mercury/Mariner 75-150 HP 4-Stroke EFI Outboards is a direct-fit aftermarket replacement for a range of 4-strokeEFI engines from 75 HP to 150 HP (2001–2014). It is a critical component for regulating engine temperature, ensuring optimal performance, longevity, and fuel efficiency. This assembly is designed to fit models within specific serial number ranges, so verification is essential.
It provides a direct interchange for Mercury part numbers 892864T06 and 892864A06, which are superseded by 8M0090819. It also cross-references with aftermarket equivalents like Sierra 18-3635-K and JLM Marine AM892864T06.
- Engineered as a direct-fit OEM replacement for a hassle-free installation.
- Comes as a complete kit including the housing, thermostat, O-ring, and clamp.
- Maintains a factory-specified 48.8°C/50°C (120°F) operating temperature.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Superseded By | Notes |
|---|---|---|---|
| Mercury | 892864T06 | 8M0090819 | OEM Part |
| Mercury | 892864A06 | Alternative OEM Part | |
| Sierra | 18-3635-K | Aftermarket cross-reference | |
| JLM Marine | AM892864T06 | Aftermarket cross-reference |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Mercury/Mariner outboards, it is critical to verify your engine's serial number against the specified ranges to ensure proper fitment.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | EFI | 75 | 4-Stroke | 2001–2009 | 892864T06 | Serial range: 1B366823-2B094995 |
| Mercury | EFI | 80 | 4-Stroke | 2001–2009 | 892864T06 | Serial range: 0P459572-2B094995, 1B366823-2B094995 |
| Mercury | EFI | 90 | 4-Stroke | 2001–2009 | 892864T06 | Serial range: 1B366823-2B094995 |
| Mercury | EFI | 100 | 4-Stroke | 2001–2009 | 892864T06 | Serial range: 0P459572-2B094995, 1B366823-2B094995 |
| Mercury | EFI | 115 | 4-Stroke | 2001–2009 | 892864T06 | Serial range: 1B366823-2B094995 |
| Mercury | EFI | 150 | 4-Stroke | 2001–2014 | 892864T06 | Serial range: 1B905505 & Up |
Technical Specs
- Product Type
- Thermostat Kit with Housing Assembly
- Installation
- Direct-fit OEM replacement
- Fuel Type
- Gasoline
- Housing Material
- Marine-grade metal alloy
- Dimensions
- Approximately 100 mm × 90 mm × 150 mm
- Operating Temperature
- 48.8°C/50°C (120°F) rated temperature
- Other Technical Attributes
- Complete assembly with housing, thermostat, O-ring and clamp
What’s in the Box
- 1 x Thermostat Assembly with Housing (892864T06/8M0090819)
- 1 x O-ring Seal (8M005958)
- 1 x Clamp (888988008)
Installation Notes
- Disconnect the negative battery cable before beginning work.
- Allow the engine to cool completely and drain the engine's cooling system.
- Locate the thermostat housing on the engine block or cylinder head.
- Disconnect any hoses attached to the housing and remove the mounting bolts.
- Carefully remove the old housing assembly. Note the orientation of the old thermostat.
- Thoroughly clean the gasket mating surfaces on the engine to remove any old sealant or corrosion.
- Install the new thermostat into the housing, ensuring it is oriented correctly.
- Place the new O-ring or gasket onto the housing and position the assembly on the engine.
- Install and tighten the mounting bolts to the manufacturer's specified torque. Do not overtighten.
- Reconnect all hoses and secure with clamps.
- Refill the cooling system with the appropriate coolant.
- Reconnect the battery, start the engine, and carefully check for any leaks. Monitor the temperature gauge to ensure it reaches and maintains the correct operating temperature.
Troubleshooting & FAQ
How do I know if my thermostat is failing?
Common signs of a faulty thermostat include engine overheating, the engine failing to reach normal operating temperature (running too cold), erratic temperature gauge readings, and coolant leaks from the housing area.
Will this fit my engine if it's not listed?
If your engine's model, year, and serial number are not listed in the compatibility chart, this part is likely not correct. Using the wrong thermostat can cause engine damage. Always verify fitment before purchasing.
What is the difference between a 120°F and a 143°F thermostat?
This is a 48.8°C/50°C (120°F) rated thermostat. Different engines require different temperature ratings for optimal performance, especially depending on whether they are used in freshwater or saltwater. Always use the temperature rating specified for your engine model.
aopCan I reuse my old O-ring or housing?
No. This kit includes a new housing, thermostat, O-ring, and clamp. It is critical to replace all these components together to ensure a proper seal and prevent leaks or future failures.
When should I replace my thermostat?
Thermostats are a routine maintenance item. It is best practice to inspect them annually and consider replacement every 3-5 years or in accordance with your engine's service manual, particularly for boats operated in saltwater.
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
p>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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