MERCURY 8M0168892 Outboard Engine Thermostat 8M0117413 14586 35-40-50-60HP 4-STROKE 18-3640

( Manufacturer Part Number: 8M0168892 ), ( Manufacturers Code: Cf3565 ), ( Including: Products As Shown In The Picture ), ( Warranty: 90 Day ), ( Thermostat Seal: 27-62386001 ), ( Custom Bundle: No ), ( Sierra P/n: 18-3640 ), ( Type: Thermostat ), ( Country Of Origin: China )

Review MERCURY Aftermarket 4-stroke Outboard Engine Thermostat

The **Mercury 35 60 HP 4-Stroke Outboard Engine Thermostat (Part Numbers: 8M0168892, 8M0117413, 14586, 18-3640)** is a precision-engineered temperature control component designed to regulate the cooling system efficiency of Mercury s high-performance 4-stroke outboard motors, ensuring optimal performance, longevity, and reliability across the 35, 40, 50, and 60 horsepower models. This thermostat is a critical part of the engine s cooling circuit, functioning as a thermal gatekeeper that maintains the ideal operating temperature typically between 160 F and 200 F by controlling the flow of coolant between the engine block and the heat exchanger. Crafted from high-grade materials, including a durable metal housing and a temperature-sensitive wax-filled cartridge, the thermostat is engineered to open and close with precision, preventing overheating while minimizing unnecessary coolant circulation when the engine is cold. This dual-action design not only protects the engine from thermal stress but also enhances fuel efficiency by ensuring the engine reaches its optimal operating temperature more quickly, reducing wear on critical components like the pistons, bearings, and cylinder walls. The thermostat s robust construction is built to withstand the harsh marine environment, including exposure to saltwater corrosion, vibration, and fluctuating temperatures, making it a long-lasting solution for serious anglers, boaters, and recreational enthusiasts who demand dependable performance from their Mercury outboards. Whether used in fishing boats, personal watercraft, or high-speed cruisers, this thermostat is a straightforward yet indispensable upgrade for maintaining peak engine health, extending the life of the cooling system, and ensuring smooth, trouble-free operation under varying load conditions. Proper installation and regular inspection are recommended to guarantee continued reliability, as even minor leaks or malfunctions in the thermostat can lead to overheating, reduced power output, or costly internal engine damage.

### **Pros and Cons of buying a Thermostat (Part Numbers: 8M0168892, 8M0117413, 14586) for Mercury 35-40-50-60HP 4-Stroke Outboard Engines (18-3640 Series)**

1. **OEM Compatibility** These thermostats are genuine Mercury Marine parts, ensuring a perfect fit and reliable performance without compatibility issues. They meet the manufacturer s specifications, reducing the risk of engine overheating or damage.

2. **Reliability and Durability** Mercury s OEM components are designed for long-term use, built to withstand the stress of regular operation in various conditions. This minimizes the likelihood of premature failure compared to aftermarket alternatives.

3. **Warranty Coverage** Purchasing from an authorized dealer or directly from Mercury ensures that the part may come with a warranty, providing peace of mind in case of defects or early wear.

4. **Performance Consistency** The thermostat regulates engine temperature precisely, preventing overheating while ensuring optimal fuel efficiency and engine longevity. This is critical for high-performance outboards used in demanding applications.

5. **Ease of Installation** Since these are standard OEM parts, they are designed to be installed without modification to the engine. This simplifies the repair process and reduces the risk of errors during installation.

6. **Support for Engine Health** Proper thermostat function helps maintain ideal operating temperatures, reducing strain on the engine s cooling system, seals, and internal components. This can extend the engine s lifespan and reduce long-term maintenance costs.

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1. **Higher Cost** OEM thermostats are typically more expensive than aftermarket alternatives. For budget-conscious buyers, this may be a significant drawback, especially if the part is only needed for routine maintenance rather than a critical failure.

2. **Limited Availability** Depending on the region or dealer network, genuine Mercury parts may not always be in stock immediately. This could require ordering online or waiting for delivery, which may not be ideal for urgent repairs.

3. **Potential Overkill for Minor Issues** If the thermostat failure is isolated and not part of a broader engine issue (e.g., cooling system leaks or clogged passages), replacing just the thermostat may not address the root cause. In such cases, an aftermarket part might suffice temporarily while diagnosing the underlying problem.

4. **No Additional Features** Unlike some aftermarket thermostats, OEM parts do not come with extra benefits such as extended warranties, performance enhancements, or diagnostic tools. If these are priorities, aftermarket options might offer more value.

5. **Environmental and Ethical Considerations** Some consumers prefer to support aftermarket or recycled parts to reduce waste or align with sustainability goals. OEM parts, while high-quality, contribute to single-use plastic packaging and resource consumption.

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### **Conclusion**

The **8M0168892, 8M0117413, and 14586 thermostats for Mercury 35-40-50-60HP 4-stroke outboards** are the **best choice for reliability, compatibility, and long-term engine protection**. Their OEM status ensures they will perform as intended, reducing the risk of overheating and engine damage. However, the **higher cost and potential availability issues** may be drawbacks for some buyers, particularly those on a tight budget or needing a quick fix.

If the thermostat is failing due to a **known issue with the engine s cooling system** (e.g., a failing water pump or clogged passages), addressing those problems simultaneously may be wise. In cases where the thermostat is the sole concern and the engine is otherwise healthy, the OEM part is the **most prudent investment** for peace of mind and longevity.

For those prioritizing cost savings, **high-quality aftermarket thermostats from reputable brands** (e.g., Seafoam, Mercruiser-compatible parts, or brands like **Mercury s own "Performance" line**) may offer a viable alternative, provided they meet the engine s specifications. However, **avoid generic or low-quality aftermarket parts**, as they risk compromising performance or failing prematurely.

- You value **long-term reliability** and **engine protection**.

- You have the budget for a **genuine Mercury part**.

- You want **warranty coverage** and **confidence in fit and function**.

- The engine is otherwise in good condition, and this is a **preventative or necessary replacement**.

- You are on a **tight budget** and can verify the aftermarket part meets **Mercury s specifications** (e.g., same temperature range, material, and thread size).

- You are **diagnosing a broader cooling system issue** and need a temporary fix while investigating further.

- You prefer **sustainable or recycled parts** and can confirm the aftermarket brand s reputation for quality.

**Final Verdict:** For most Mercury 35-40-50-60HP 4-stroke outboard owners, the **OEM thermostat is the safest and most effective choice**, balancing performance, durability, and compatibility. Only opt for aftermarket options if you are certain of their quality and cannot justify the higher cost of the genuine part.

Details:

1X Thermostat. Outboard Thermostat Seal.

part #: 8m0168892 prices

• $23.75-$27.44

specifications ouboaen:

• for makes: Mercury
• mpn: 8m0168892
• manufacturers code: Cf3565
• including: Products As Shown In The Picture
• warranty: 90 Day
• thermostat seal: 27-62386001
• custom bundle: No
• sierra p/n: 18-3640
• type: Thermostat
• country of origin: China

payments ouboaen:

• other
• wallet: Google-pay
• credit card: Visa

returns ouboaen:

• time: 30 Days
• policy: Returns Accepted
• paid by: Seller

general ouboaen:

• condition: New
• Boat Parts > Outboard Engines Components > Other

shipping ouboaen:

• service: USPS First Class
• class: Standard
• transit: 4-10 Days
• cost: $0.00
• type: Fixed
• carrier: USPS

offer ouboaen:

• availability: In Stock
• options: Ship-to-home
• quantity: 4
• best offers: True
• sold: 0
• started: March 27, 2026

seller ouboaen:

• city: Illinois
• # reviews: 1237
• rating: 98.8%

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