Thermostat Kit – Fits Mercury/Mariner 6-25 HP Outboard Motors (Replaces 14586A3, 75692A10)

Thermostat Kit – Fits Mercury/Mariner 6-25 HP Outboard Motors (Replaces 14586A3, 75692A10)

This thermostat service kit is designed for Mercury/Mariner 2-Stroke outboards from 6 HP to 25 HP manufactured between 1984 and 1998, including Standard, Sea Pro, and Super 15 models. While some sources suggest partial interchangeability with 4-Stroke models, compatibility data is incomplete; please verify fitment for 4-Stroke engines independently.

This kit is a direct replacement for multiple OEM and aftermarket part numbers, ensuring broad compatibility for the specified engine range. It is engineered to meet or exceed original equipment specifications for reliable performance in both saltwater and freshwater environments.

• Engineered for direct, hassle-free installation.
• Includes thermostat, gaskets, and seal for a complete service.
• Features a 120°F (50°C) nominal operating temperature.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Technical Specifications

Package Contents

• 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 Guide

1. Safety First: Disconnect the battery and ensure the engine is completely cool.
2. Drain Coolant: Place a container below the engine and drain the cooling system.
3. Locate Housing: Find the thermostat housing on the engine block.
4. Remove Cover: Unscrew the bolts holding the thermostat cover in place and carefully remove it.
5. Remove Old Parts: Take out the old thermostat, gasket, and seal. Note their orientation.
6. Clean Surfaces: Thoroughly clean the mating surfaces of the housing and cover, removing any old gasket material or corrosion.
7. Install New Kit: Place the new thermostat, gasket, and seal into the housing in the correct order and orientation.
8. Reassemble: Re-install the cover and tighten the bolts to the manufacturer's specified torque.
9. Refill & Check: Refill the cooling system. Start the engine and let it warm up, checking carefully for any leaks around the housing.

Troubleshooting & FAQ

Q: How do I check if this kit fits my specific engine model?

A: The best way to confirm fitment is by checking your serial number against the ranges listed in the "Compatible Engine Models" table above. You can use the provided Mercury Serial Number Guide to find and identify your number. Cross-referencing the part number of your old thermostat with our cross-reference list also helps ensure a match.

Q: What are common signs that my outboard's thermostat is failing?

A: A thermostat can fail by sticking open or closed. If it sticks open, your engine may not reach its proper operating temperature, leading to poor performance and carbon buildup. If it sticks closed, the engine will overheat, which can cause significant damage. An alarm or a temperature gauge reading higher than normal are key indicators.

Q: Why is the temperature rated at 120°F (50°C)?

A: This 120°F rating is the OEM-specified temperature for these Mercury/Mariner models. It ensures the engine warms up quickly but remains cool enough for optimal performance and fuel efficiency, particularly in raw water-cooled systems. Using the correct temperature thermostat is critical for engine longevity.

Q: OEM vs. Aftermarket?

A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

Q: How fast do you ship and how much does it cost?

A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

Q: What is your warranty and return policy?

A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.