Thermostat Kit (143°F/62°C) – Fits Mercury Marine 135-200 HP V6 Outboards (Replaces 75692Q2, 75692T)

Thermostat Kit (143°F/62°C) – Fits Mercury Marine 135-200 HP V6 Outboards (Replaces 75692Q2, 75692T)

This thermostat kit is a direct replacement for specific Mercury Marine V6 outboard engines, including models with horsepower ratings of 135-150 HP (S/N A904646+), 175 HP (S/N C100861+), and 200 HP (S/N 6435503+). It is engineered to maintain the engine's optimal operating temperature of 143°F (62°C).

It directly replaces Mercury parts 75692Q2, 75692T, and 75692, along with popular aftermarket equivalents from Sierra, GLM, and Mallory. Please note, this kit will not fit DFI Optimax motors.

• Engineered for a precise fit and reliable performance in marine outboard cooling systems.
• Maintains a consistent operating temperature of 143°F (62°C).
• Includes a complete set of two thermostats and four gaskets for a full replacement.

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

• 2 x Thermostat (Replaces 75692Q2)
• 4 x Rubber Gasket Seals (2 per thermostat)

Installation Guide

1. Ensure the engine is off and cool. Disconnect the negative battery cable for safety.
2. Drain the engine coolant into a suitable container.
3. Locate the thermostat housing on the engine block or cylinder head.
4. Carefully remove the bolts or screws securing the housing cover.
5. Remove the old thermostat and gaskets. Note the orientation of the thermostat.
6. Thoroughly clean the mating surfaces of the housing and cover to remove old gasket material and corrosion.
7. Install the new thermostat in the correct orientation, followed by the new gaskets.
8. Re-attach the housing cover and tighten the bolts to the manufacturer's specified torque.
9. Refill the cooling system with the appropriate coolant.
10. Reconnect the battery cable, start the engine, and carefully check the housing for any leaks.
11. Allow the engine to reach operating temperature, monitoring the temperature gauge to ensure it is stable.

Troubleshooting & FAQ

Q: How do I confirm this thermostat kit will fit my engine?
A: The most reliable method is to check your engine's serial number against the ranges listed in the compatibility chart. For Mercury V6 models, this kit fits 135-150 HP (S/N A904646+), 175 HP (S/N C100861+), and 200 HP (S/N 6435503+). Also, cross-reference your existing part number with those provided.

Q: Will this kit work with Mercury DFI Optimax motors?
A: No, this kit is not compatible with DFI (Direct Fuel Injection) Optimax engines. Using it on an unsupported model can lead to improper engine temperatures and potential damage.

Q: What are the signs of a failing thermostat?
A: Common symptoms include engine overheating (if the thermostat is stuck closed) or the engine failing to reach its normal operating temperature (if stuck open). Both conditions can negatively affect performance, fuel economy, and long-term engine health.

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.