Thermostat Kit 120° – Fits Mercury/Mariner 6-25 HP 2-Stroke (Replaces 14586A3, 75692A9)
Thermostat Kit 120° – Fits Mercury/Mariner 6-25 HP 2-Stroke (Replaces 14586A3, 75692A9) 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 120° – Fits Mercury/Mariner 6-25 HP 2-Stroke (Replac...
Thermostat Kit 120° – Fits Mercury/Mariner 6-25 HP 2-Stroke (Replaces 14586A3, 75692A9) is backordered and will ship as soon as it is back in stock.
Product Details
This Thermostat Kit 120° – Fits Mercury/Mariner 6-25 HP 2-Stroke (Replaces 14586A3, 75692A9) is designed for a range of Mercury and Mariner 2-stroke outboard engines from 6 HP to 25 HP, covering models manufactured between 1986 and 1998+. The kit provides a 120°F (49°C) thermostat and the necessary gaskets for a complete cooling system service.
It serves as a direct replacement for multiple OEM and aftermarket part numbers, including Mercury 14586A3, 75692A9, Sierra 18-3549, and Mallory 9-43052, ensuring broad interchange compatibility.
- Engineered for direct replacement installation.
- Maintains optimal engine temperature at 120°F (49°C).
- Includes all essential gaskets required for a complete thermostat service.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 14586A3 |
| Mercury | 75692A9 |
| Mercury | 75692A10 |
| Mercury | 75692A11 |
| Sierra | 18-3549 |
| Sierra | 18-43052 |
| GLM | 13121 |
| Mallory | 9-43014 |
| Mallory | 9-43052 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Mercury and Mariner models, it is crucial to verify your engine's serial number to ensure correct fitment, as specified in the 'Notes' column.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | Standard | 6 | 2-Stroke | 1986–1998 | 14586A3 | Serial Range: 0A197112 & Up (USA) |
| Mercury | Standard | 6 | 2-Stroke | 1986–1993 | 14586A3 | Serial Range: 9461526 & Up (BEL) |
| Mercury | Standard | 8 | 2-Stroke | 1986–1998 | 14586A3 | Serial Range: 0A197112 & Up (USA) |
| Mercury | Standard | 8 | 2-Stroke | 1986–1993 | 14586A3 | Serial Range: 9461526 & Up (BEL) |
| Mercury | Standard | 9.9 | 2-Stroke | 1986–1998 | 14586A3 | Serial Range: 0A197112 & Up (USA) |
| Mercury | Standard | 9.9 | 2-Stroke | 1986–1993 | 14586A3 | Serial Range: 9461526 & Up (BEL) |
| Mercury | Standard | 15 | 2-Stroke | 1988–1998 | 14586A3 | Serial Range: 0B292414 & Up (USA) |
| Mercury | Standard | 15 | 2-Stroke | 1988–1993 | 14586A3 | Serial Range: 9542620 & Up (BEL) |
| Mercury | Sea Pro | 15 | 2-Stroke | 1994–1998 | 14586A3 | Serial Range: 0G044365 & Up (USA) |
| Mercury | Sea Pro | 15 | 2-Stroke | 1997–1998 | 14586A3 | Serial Range: 9927000 & Up (BEL) |
| Mercury | Super | 15 | 2-Stroke | 1988–1998 | 14586A3 | Serial Range: 0B238464 & Up (USA) |
| Mercury | Super | 15 | 2-Stroke | 1988–1998 | 14586A3 | Serial Range: 9507381 & Up (BEL) |
| Mercury | Super | 15 | 2-Stroke | 1988–1998 | 14586A3 | Serial Range: 0A730007 & Up (CAN) |
| Mercury | Standard | 20 | 2-Stroke | 1986–1987 | 14586A3 | Serial Range: 0B114231 & Up (USA) |
| Mercury | Standard | 20 | 2-Stroke | 1986–1987 | 14586A3 | Serial Range: 9467988 & Up (BEL) |
| Mercury | Standard | 20 | 2-Stroke | 1986–1987 | 14586A3 | Serial Range: 0A719661 & Up (CAN) |
| Mercury | Standard | 25 | 2-Stroke | 1984–1987 | 14586A3 | 2-Cylinder, Serial Range: 0B114231 & Up (USA) |
| Mercury | Standard | 25 | 2-Stroke | 1984–1987 | 14586A3 | 2-Cylinder, Serial Range: 9467988 & Up (BEL) |
| Mercury | Standard | 25 | 2-Stroke | 1984–1987 | 14586A3 | 2-Cylinder, Serial Range: 0A719661 & Up (CAN) |
| Mercury | Sea Pro | 25 | 2-Stroke | 1988–1998 | 14586A3 | Serial Range: 0B238464 & Up (USA) |
| Mercury | Sea Pro | 25 | 2-Stroke | 1988–1994 | 14586A3 | Serial Range: 9507381 & Up (BEL) |
| Mercury | Sea Pro | 25 | 2-Stroke | 1988–1994 | 14586A3 | Serial Range: 0A730007 & Up (CAN) |
Technical Specs
- Product Type
- Thermostat Service Kit
- Installation
- Direct Replacement
- Temperature Rating
- 120°F (49°C)
- Operating Temperature
- 120°F (49°C) nominal
- Weight
- 42 g (1.5 oz)
What’s in the Box
- 1 x Thermostat (14586)
- 1 x Thermostat Seal/Ring Rubber (62386001/27-62386)
- 1 x Thermostat Cover Gasket (14318/27-14318-3)
- 1 x Thermostat Gasket (19205/27-19205-1)
Installation Notes
- Ensure the engine is off, cool, and disconnected from the battery.
- Drain the cooling system to a level below the thermostat housing.
- Locate and unbolt the thermostat housing cover.
- Carefully remove the old thermostat, seal, and any gasket remnants.
- Thoroughly clean the mating surfaces of the housing and its cover.
- Install the new thermostat, seal, and correct gaskets as per your engine's service manual.
- Re-secure the housing cover and torque bolts to manufacturer specifications.
- Refill the cooling system, check for leaks, and run the engine to verify proper operation.
Troubleshooting & FAQ
How do I know if my thermostat needs replacing?
Common signs of a failing thermostat include engine overheating (stuck closed), running too cool (stuck open), or erratic temperature gauge readings. A visual inspection may show corrosion or a stuck valve.
Why are there multiple gaskets in this kit?
This kit is designed to service a wide range of models that may use slightly different gasket configurations. Match the new gaskets to your original parts and discard any extras.
Is 120°F the correct temperature for my engine?
This thermostat is set to a 120°F (49°C) rating, which is the standard specification for the listed Mercury/Mariner models. Using the correct temperature thermostat is vital for engine performance and longevity.
Can I install this myself?
While installation is straightforward for those with mechanical experience, consulting a service manual is critical. If you are unsure, professional installation is recommended to prevent cooling system leaks or damage.
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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