Thermostat Kit – Fits Mercury/Mariner 6-25 HP (Replaces 14586A3, 75692A10)
Thermostat Kit – Fits Mercury/Mariner 6-25 HP (Replaces 14586A3, 75692A10) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
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Thermostat Kit – Fits Mercury/Mariner 6-25 HP (Replaces 14586A3, 75...
Thermostat Kit – Fits Mercury/Mariner 6-25 HP (Replaces 14586A3, 75692A10) is backordered and will ship as soon as it is back in stock.
Product Details
This Thermostat Kit – Fits Mercury/Mariner 6-25 HP Outboard Motors ensures your engine maintains the correct operating temperature for optimal performance and longevity. It is engineered for a wide range of Mercury/Mariner 2-stroke outboards from 6 HP to 25 HP manufactured between 1984–1998, including Standard, Sea Pro, and Super 15 models.
This kit serves as a direct replacement for multiple OEM and aftermarket part numbers, including Mercury 14586, 14586A3, 75692A9, 75692A10, 75692A11, Sierra 18-3549, and Mallory 9-43052.
- Engineered for direct-fit installation.
- Provides marine-grade corrosion resistance for salt and freshwater use.
- Includes thermostat, gaskets, and seal for a complete service.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 14586 |
| Mercury | 14586A3 |
| Mercury | 75692A9 |
| Mercury | 75692A10 |
| Mercury | 75692A11 |
| Sierra | 18-0323 |
| 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.
Fits various 2-stroke Mercury and Mariner outboards. While some sources suggest partial interchangeability with 4-stroke models, compatibility is only confirmed for the 2-stroke engines listed here.
| 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 (50°C) nominal
- Operating Temperature
- 120°F (50°C) nominal
- Other Technical Attributes
- Marine-grade corrosion resistance for salt/fresh water applications
- Warranty
- Typically 1-year against manufacturing defects (varies by manufacturer)
What’s in the Box
- 1 x Thermostat (Replaces 14586)
- 1 x Thermostat Seal/Ring Rubber (Replaces 62386001/27-62386)
- 1 x Thermostat Cover Gasket (Replaces 14318/27-14318-3)
- 1 x Thermostat Gasket (Replaces 19205/27-19205-1)
Installation Notes
- Ensure the engine is off, cool, and disconnected from the battery.
- Drain the engine block cooling system to a level below the thermostat housing.
- Locate and remove the thermostat housing cover, noting the orientation of bolts and gaskets.
- Remove the old thermostat, seal, and any gasket residue. Clean all mating surfaces thoroughly.
- Install the new thermostat, seal, and gaskets in the correct order and orientation.
- Re-install the housing cover and torque bolts to the manufacturer's specification.
- Refill the cooling system, reconnect the battery, and start the engine. Check for leaks and verify normal temperature operation.
Troubleshooting & FAQ
How do I know if my thermostat is failing?
Common signs of a faulty thermostat include engine overheating, running too cold (not reaching optimal temperature), erratic temperature gauge readings, or visible coolant leaks around the thermostat housing.
Will this fit a 4-stroke model?
This kit is specifically documented for 2-stroke Mercury/Mariner engines from 6-25 HP. While some cross-references suggest potential 4-stroke compatibility, we cannot guarantee it. Please verify your OEM part number before ordering.
What is the correct operating temperature for this thermostat?
This thermostat is rated for a nominal operating temperature of 120°F (50°C). This allows the engine to warm up quickly and maintain a stable temperature for efficient combustion and reduced wear.
How often should a thermostat be replaced?
Thermostats don't have a strict replacement interval, but it's good practice to inspect them during routine cooling system service (e.g., water pump replacement) or replace them every 3-5 years, especially if operating in saltwater.
Can I install this myself?
Yes, this is a common DIY task for those with basic mechanical skills. However, to ensure safety and prevent damage, professional installation is always recommended if you are unsure about the process.
What happens if the engine runs too cold?
An engine that runs below its optimal temperature (due to a stuck-open thermostat) can suffer from incomplete fuel combustion, carbon buildup, increased internal wear, and reduced fuel efficiency.
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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