Thermostat Kit (130°F/54°C) for Mercury 200–300 HP 2-Stroke Outboards — Replaces 8M0057307 and 885599004
Thermostat Kit (130°F/54°C) for Mercury 200–300 HP 2-Stroke Outboards — Replaces 8M0057307 and 885599004 is backordered and will ship as soon as it is back in stock.
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Thermostat Kit (130°F/54°C) for Mercury 200–300 HP 2-Stroke Outboar...
Thermostat Kit (130°F/54°C) for Mercury 200–300 HP 2-Stroke Outboards — Replaces 8M0057307 and 885599004 is backordered and will ship as soon as it is back in stock.
Product Details
This 130°F (54°C) thermostat kit is designed for selected Mercury Marine 200–300 HP V6 two-stroke outboard applications, including 2.5L and 3.0L DFI/EFI configurations and certain 3.2L models. The thermostats help regulate engine operating temperature as part of the outboard cooling system.
Catalog references identify this 130°F thermostat application with Mercury OEM part number 8M0057307 and reference number 885599004. Confirm the engine model, two-stroke configuration, and serial-number range against your service information before ordering.
- 130°F (54°C) thermostat rating.
- Designed for selected Mercury Marine 200–300 HP two-stroke outboards.
- Suitable for applicable 2.5L and 3.0L DFI/EFI V6 applications and certain 3.2L models.
- Kit includes two thermostats and two thermostat-cover gaskets.
Part Number References
Use these manufacturer and catalog references when comparing your original parts. Part-number references do not replace model and serial-number verification.
| Brand | Reference | Description |
|---|---|---|
| Mercury | 8M0057307 | 130°F thermostat reference |
| Mercury | 885599004 | Reference for selected 200–300 HP applications |
| Mercury | 27-850318-1 | Thermostat-cover gasket reference |
Engine Compatibility
This kit is intended for selected two-stroke Mercury Marine outboards, not general four-stroke applications. The catalog application range includes 200–300 HP models and 2.5L/3.0L DFI-related applications. Certain 3.2L models may also use the same thermostat reference.
| Brand | Application | Horsepower | Stroke | Displacement / System | Verification Required |
|---|---|---|---|---|---|
| Mercury Marine | Selected V6 outboard models | 200–300 HP | 2-Stroke | 2.5L and 3.0L DFI/EFI; selected 3.2L applications | Model designation and serial number |
Important: Horsepower alone does not confirm fitment. Mercury produced multiple engine configurations and serial-number ranges. Compare the thermostat and gasket with your original parts and verify the complete engine model and serial number before purchase.
Technical Specifications
- Product Type
- Thermostat kit
- Temperature Rating
- 130°F (54°C)
- Application
- Selected Mercury Marine 200–300 HP two-stroke outboard engines
- Engine Configuration
- Selected V6 DFI/EFI applications
- Displacement Scope
- 2.5L, 3.0L, and selected 3.2L applications
- Installation
- Replacement installation using the original thermostat covers and hardware
- Package Contents
- Two thermostats and two thermostat-cover gaskets
What’s in the Box
- 2 × 130°F thermostats
- 2 × thermostat-cover gaskets
Installation Notes
Work only with the engine stopped and completely cool. Follow the service procedure for your specific Mercury engine, including the manufacturer's torque specifications.
- Disconnect the battery or follow the applicable engine safety procedure to prevent accidental starting.
- Allow the engine to cool fully before opening the thermostat housings.
- Remove any components necessary to access the thermostat covers.
- Remove the cover fasteners and carefully lift off the thermostat covers. Be prepared for residual coolant.
- Remove the old thermostats and gaskets, noting the orientation of each thermostat.
- Clean the mating surfaces without damaging the covers or cylinder-head sealing surfaces.
- Install the new thermostats in the same orientation as the originals, followed by the new gaskets.
- Reinstall the covers and tighten the fasteners to the service-manual specification.
- Restore the cooling system as required by the engine service procedure.
- Run the engine according to the service-manual instructions and check for leaks and abnormal temperature indications.
Troubleshooting & FAQ
How can I tell whether a thermostat may be failing?
Possible symptoms include abnormal operating temperature, overheating, running cooler than expected, inconsistent temperature readings, or temperature-related warning indications. Other cooling-system problems can cause similar symptoms, so inspect the complete cooling system before replacing parts.
Why is this thermostat rated at 130°F?
The 130°F rating is specified for the applicable engine cooling-system design. Use the temperature rating specified for your exact engine rather than substituting a thermostat solely because it appears physically similar.
Should both thermostats be replaced together?
Yes. This kit contains two thermostats and two gaskets for the applicable dual-thermostat service. Replacing the components together helps maintain consistent cooling-system operation.
Will this fit a Mercury four-stroke engine?
This listing is for selected Mercury two-stroke V6 applications. Do not use the horsepower number alone to determine fitment. Verify the exact model, displacement, two-stroke configuration, and serial number before ordering.
Does the kit include the thermostat covers or mounting hardware?
No. The package contains two thermostats and two thermostat-cover gaskets. Covers, bolts, seals, and other cooling-system components are not included unless specifically listed.
Is this an OEM Mercury part?
This listing is for a replacement thermostat kit. Mercury OEM and catalog reference numbers are provided for identification and compatibility comparison; the replacement kit should not be represented as a genuine Mercury-branded component.
Safety & Important Information
- Verify the complete engine model and serial number before purchase.
- Confirm that your engine is a compatible two-stroke configuration.
- Compare the thermostat temperature rating, shape, and gasket with the original parts.
- Never open the cooling system or thermostat housing while the engine is hot.
- Professional installation is recommended when the correct service procedure or torque specifications are unavailable.
About Sea Sierra
- Marine Replacement Parts — Practical replacement components for repair and maintenance applications.
- Application-Focused Listings — Product references and compatibility guidance are provided to help you compare the correct part.
- Service-Friendly Support — Use your engine model and serial number when requesting fitment assistance.
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