885599003 Thermostat 130°F for Mercury 200HP 225HP 250HP 3.0L DFI EFI | JLM Marine

Thermostat 130°F for Mercury 200HP 225HP 250HP 3.0L DFI EFI

This high-quality aftermarket thermostat is engineered for Mercury Mariner outboard motors rated 200–250 HP with 3.0L DFI and EFI engines. Designed to maintain optimal operating temperature at 130°F, it ensures reliable cooling performance across a wide range of applications from recreational to commercial use.

This thermostat directly replaces Mercury OEM part numbers 885599003, 885599004, 8855991, and 8M0057307, offering a cost-effective solution without compromising on quality or performance.

• Maintains precise engine temperature at 130°F for optimal performance
• Direct-fit replacement for Mercury 3.0L DFI and EFI outboards
• Compatible with models from 1997 and up

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

Your order includes:

• 1 × Thermostat (130°F)

Installation Guide

1. Safety First: Disconnect the battery and allow the engine to cool completely before beginning work.
2. Drain Coolant: Open the drain valve or remove the lower hose to drain coolant from the system into a suitable container.
3. Locate Thermostat Housing: Identify the thermostat housing on your engine block, typically near the cylinder head.
4. Remove Housing Bolts: Using the appropriate socket or wrench, carefully remove the bolts securing the thermostat housing cover.
5. Extract Old Thermostat: Lift out the old thermostat and inspect the housing for debris or corrosion. Clean thoroughly with a gasket scraper and solvent.
6. Install New Thermostat: Position the new thermostat in the housing with the temperature-sensing element facing the correct direction (refer to markings or your service manual).
7. Replace Gasket/Seal: Use a new gasket or O-ring to ensure a proper seal. Apply a thin layer of marine-grade sealant if recommended by the manufacturer.
8. Reinstall Housing Cover: Carefully align and secure the thermostat housing cover with bolts. Torque to manufacturer specifications in a crisscross pattern.
9. Refill Coolant: Close drain valves and refill the cooling system with the recommended coolant mixture for your outboard.
10. Bleed Air: Start the engine and allow it to reach operating temperature, watching for proper coolant circulation and bleeding any trapped air from the system.
11. Check for Leaks: Inspect all connections and the thermostat housing for leaks. Top off coolant as needed.
12. Test Run: Run the engine at idle and varying RPMs to confirm stable operating temperature and proper thermostat operation.

Troubleshooting & FAQ

Q: How do I confirm this thermostat fits my engine?
A: Cross-reference your engine's model number and serial number range with the compatibility table above. Verify that your engine is a Mercury 200–250 HP with a 3.0L DFI or EFI configuration and matches the specified serial number ranges.

Q: What are the signs that my thermostat needs replacement?
A: Common symptoms include engine overheating, running too cool (below normal operating temperature), erratic temperature fluctuations, or coolant leaks around the thermostat housing. If your temperature gauge shows abnormal readings, the thermostat may be stuck open or closed.

Q: How often should I replace the thermostat?
A: Thermostats should be inspected annually and replaced every 3–5 years or as needed based on performance. If you notice cooling system issues or during major engine service, replace the thermostat as a preventive measure.

Q: Can I install this thermostat myself, or do I need a mechanic?
A: If you have basic mechanical skills and tools, thermostat replacement is straightforward. However, proper coolant bleeding and torque specifications are critical—professional installation is recommended if you're unfamiliar with marine cooling systems.

Q: Is this an OEM thermostat or 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.