Thermostat Service Kit for Mercury and Mariner 75–120 HP 2-Stroke Outboards and SportJet Models – Cross-References F664068, 859620, 828319 and F476067
Thermostat Service Kit for Mercury and Mariner 75–120 HP 2-Stroke Outboards and SportJet Models – Cross-References F664068, 859620, 828319 and F476067 is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
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Thermostat Service Kit for Mercury and Mariner 75–120 HP 2-Stroke O...
Thermostat Service Kit for Mercury and Mariner 75–120 HP 2-Stroke Outboards and SportJet Models – Cross-References F664068, 859620, 828319 and F476067 is backordered and will ship as soon as it is back in stock.
Product Details
This thermostat service kit is intended for listed Mercury, Mariner, Force, and Mercury SportJet 2-stroke applications. It provides the thermostat and related sealing components needed when servicing the cooling system and helps maintain the engine operating temperature specified for compatible applications.
The thermostat is designed for an operating temperature of 130°F (54°C). Always compare the engine model, year, serial number, and original part numbers with the compatibility information before ordering.
Reference numbers associated with this kit include Mercury F664068, 859620, 828319, and F476067, plus aftermarket reference Sierra 18-0854.
- Aftermarket replacement service kit for listed marine-engine applications.
- Designed to help maintain the specified engine operating temperature.
- Includes the thermostat, housing gasket, and seal listed below.
- Verify the complete model and serial-number conditions before installation.
Part Number Matrix
Use these references as a cross-reference aid. Part-number matching alone does not replace verification of the complete engine model, year, stroke, and serial range.
| Brand | Part Number |
|---|---|
| Mercury | F664068 |
| Mercury | 859620 |
| Mercury | 828319 |
| Mercury | F476067 |
| Sierra | 18-0854 |
Engine & Model Compatibility
The following applications and serial conditions are listed for this service kit. Confirm the exact engine identification before purchase or installation.
| Brand | Model | Rated HP | Stroke | Years | Reference Part No. | Serial or Application Notes |
|---|---|---|---|---|---|---|
| Mercury | Outboard | 75 | 2-Stroke | 1998–1999 | F664068 | 0E288000–0E344999; 0E345000–0E369299 |
| Mercury | Outboard | 90 | 2-Stroke | 1990–1992 | F664068 | 1991E–1992C |
| Mercury | Outboard | 90 | 2-Stroke | 1990–1994 | F664068 | 0E000001–0E093699 |
| Mercury | Outboard | 90 | 2-Stroke | 1990 | F664068 | 903X90A-Up, 906A90A-Up, and 906F90A-Up applications |
| Mercury | Outboard | 90 | 2-Stroke | 1996–1997 | F664068 | 0E138600–0E202999; 0E203000–0E287999 |
| Mercury | Outboard | 90 | 2-Stroke | 1999 | F664068 | 0E345000–0E369299 |
| Mercury | Outboard | 120 | 2-Stroke | 1995 | F664068 | 0E093700–0E138599 |
| Mercury | Outboard | 120 | 2-Stroke | 1996–1997 | F664068 | 0E138600–0E202999; 0E203000–0E287999 |
| Force | Outboard | 70, 75, 85, 90, 120, 125, 150 | 2-Stroke | 1990–1999 | F664068 | Listed Force applications; verify the exact model and serial range |
| Mercury | SportJet | 90 | 2-Stroke | 1993 | F664068 | Non-Oil Injection powerhead: 0E023150–0E033710 |
| Mercury | SportJet | 90 | 2-Stroke | 1993 | F664068 | Jet drive: 0E021000–0E036999 |
| Mercury | SportJet | 90 | 2-Stroke | 1994 | F664068 | Non-Oil Injection powerhead: 0E033711–0E066619 |
| Mercury | SportJet | 90 | 2-Stroke | 1994 | F664068 | Oil Injection powerhead: 0E066620–0E095087 |
| Mercury | SportJet | 95XR | 2-Stroke | 1996 | F664068 | Powerhead: 0E141089–0E202999 |
| Mercury | SportJet | 95XR | 2-Stroke | 1996 | F664068 | Jet drive: 0E145580–0E151579 |
| Mercury | SportJet | 95XR | 2-Stroke | 1997 | F664068 | Powerhead: 0E203000–0E315904 |
| Mercury | SportJet | 95XR | 2-Stroke | 1997 | F664068 | Jet drive: 0E151580–0E288445 |
| Mercury | SportJet | 120 | 2-Stroke | 1995 | F664068 | Powerhead: 0E095088–0E141088 |
| Mercury | SportJet | 120 | 2-Stroke | 1995 | F664068 | Jet drive: 0E080400–0E145579 |
Technical Specifications
- Product Type
- Thermostat service kit with gasket and seal
- Application
- Listed Mercury, Mariner, Force, and SportJet 2-stroke applications
- Installation
- Replacement installation using the original housing and fasteners
- Housing Material
- Metal
- Housing Color
- Brass/gray
- Operating Temperature
- 130°F (54°C)
- Product Type
- Aftermarket replacement
What’s in the Box
- 1 × Thermostat, reference F664068
- 1 × Thermostat housing gasket, reference 828319
- 1 × Thermostat seal, reference F664914
Installation Notes
- Disconnect the battery and allow the engine to cool completely before beginning work.
- Locate the thermostat housing and place a suitable drain pan beneath the service area.
- Remove the housing-cover fasteners and note the orientation of the original components.
- Remove the old thermostat, gasket, and seal.
- Clean the mating surfaces thoroughly and remove old gasket material and corrosion.
- Install the replacement thermostat in the correct orientation, then fit the new seal and gasket.
- Reinstall the housing cover and tighten the fasteners to the engine manufacturer’s specified torque.
- Restore the cooling system as required, check for leaks, and run the engine to verify proper water flow and temperature regulation.
Troubleshooting & FAQ
How do I confirm fitment?
Compare the engine brand, model, horsepower, stroke, year, and serial number with the compatibility table. Also compare the original thermostat and gasket references. If any identification detail differs, consult a qualified marine technician before ordering.
What are common signs of a failing thermostat?
Possible symptoms include overheating at low speed, an engine that runs unusually cool, inconsistent temperature readings, or temperature changes that do not match operating conditions. A thermostat may stick open or closed.
What temperature is this thermostat designed for?
The listed thermostat operating temperature is 130°F (54°C). Use the specification appropriate to the exact engine application.
What should be replaced during thermostat service?
For a reliable seal, inspect the thermostat housing and mating surfaces and replace the thermostat, housing gasket, and seal when they show wear, damage, corrosion, or loss of sealing performance.
Is this an OEM component?
No. This listing is for an aftermarket replacement service kit. The displayed Mercury and Sierra numbers are reference or cross-reference numbers used to help identify the listed application.
Safety & Important Information
- Confirm the complete model and serial-number conditions before purchase.
- Compare the replacement parts with the original components before installation.
- Do not work on a hot engine or pressurized cooling system.
- Professional installation is recommended when the correct procedure or torque specifications are uncertain.
- This is an aftermarket replacement, not an OEM component.
About Sea Sierra
- Marine replacement parts selected for practical service and maintenance applications.
- Product information is organized around part-number and engine-application references.
- Always verify fitment and installation requirements before ordering or servicing an engine.
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