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Outboard Motor Parts | Mercury, Yamaha, Suzuki & More
Shop outboard motor parts for maintenance, repair, troubleshooting, and full marine engine rebuild projects. This category includes OEM parts and quality OEM specification aftermarket products from Pro Marine, along with replacement marine parts for Chrysler Force, Honda, Johnson Evinrude E-tec, Mercury, Suzuki, Tohatsu Nissan, and Yamaha outboard engines.
Use this section to browse outboard parts by brand and engine system, including cooling, fuel delivery, ignition and electrical, intake, internal engine components, lower unit parts, steering, trim, transom, midsection, engine oil, service kits, gaskets, seals, carburetor parts, water pump parts, and rebuild components.
Shop Outboard Categories
Chrysler / Force Outboard Parts for Chrysler and Force outboard repair 
Honda Outboard Honda cooling, fuel, electrical, and engine parts 
Johnson / Evinrude / E-tec Outboard OMC, Johnson, Evinrude, and E-tec parts 
Mercury Outboard Mercury and Mariner service and rebuild parts 
Suzuki Outboard Suzuki maintenance, lower unit, and engine parts 
Tohatsu / Nissan Outboard Tohatsu and Nissan outboard replacement parts 
Yamaha Outboard Yamaha service, repair, and rebuild parts Common Outboard Parts Found in This Category
- Water pump kits, impellers, thermostats, and cooling system parts
- Carburetor kits, fuel pumps, fuel filters, and fuel system components
- Ignition coils, stators, switch boxes, rectifiers, sensors, and electrical parts
- Pistons, piston rings, bearings, crankshafts, sleeves, gaskets, and rebuild parts
- Lower unit seals, bearings, gears, driveshaft parts, and gearcase components
- Steering parts, control cables, trim parts, and transom components
- Engine oil, gear lube, service kits, spark plugs, seal kits, and routine maintenance parts
Common Outboard Problems and Where to Start
- Overheating: inspect the water pump, impeller, thermostat, cooling passages, and engine anodes.
- Hard starting or rough idle: check carburetor parts, fuel delivery, ignition components, spark plugs, and intake sealing.
- Weak spark or no spark: test ignition coils, stators, switch boxes, sensors, wiring, and related electrical components.
- Low compression or poor power: inspect pistons, rings, gaskets, cylinder condition, bearings, and internal engine components.
- Milky gear lube or gearcase noise: check lower unit seals, bearings, gears, driveshaft parts, and prop shaft components.
Frequently Asked Questions
What is the difference between OEM and aftermarket outboard parts?
OEM parts are made by the original engine manufacturer. Aftermarket parts are replacement parts made by other manufacturers to fit the same application. Pro Marine provides quality OEM specification aftermarket products designed for marine maintenance, repair, and rebuild work.
How do I find parts for my outboard engine?
Start by selecting your outboard brand, then choose the correct engine system category. Use your model number, serial number, horsepower, and year range to confirm fitment before ordering parts.
What information do I need before ordering outboard parts?
You should have the engine manufacturer, horsepower, model number, serial number, and any OEM part numbers from the original component when available. This helps avoid ordering parts that look similar but fit a different engine family.
Are aftermarket outboard parts reliable?
Yes, quality aftermarket outboard parts are commonly used by marine mechanics and rebuilders. Pro Marine offers OEM specification aftermarket products for many common outboard repair, maintenance, and rebuild applications.
What brands are included in the outboard category?
This category includes Chrysler Force, Honda, Johnson Evinrude E-tec, Mercury, Suzuki, Tohatsu Nissan, and Yamaha outboard parts.
Tip: Before ordering outboard parts, confirm your engine brand, horsepower, model number, serial number, and year range whenever possible.
6CE-44352-00-00
6CE-44352P
8M0175392
8M6010334
Pro Marine 130°F V6 Outboard Thermostat
Mercury & Mariner 2.5L / 3.0L EFI & DFI Thermostat
The Pro Marine 9004 thermostat is a replacement 130°F marine thermostat for select Mercury and Mariner 175HP-300HP EFI, DFI, OptiMax, Pro Max, and Pro XS outboards.
Designed for high-performance Mercury V6 applications, this thermostat helps maintain proper engine operating temperature for cooling system efficiency, engine protection, and dependable outboard performance.
Compatible Applications
| Horsepower Range | Engine Family | Engine Type | Application Notes |
|---|---|---|---|
| 175HP-200HP | Mercury V6 2.5L | EFI | Select EFI cooling system applications |
| 175HP-200HP | Mercury V6 2.5L | DFI / OptiMax | Select OptiMax thermostat applications |
| 200HP-300HP | Mercury V6 3.0L | EFI | Select EFI cooling systems |
| 200HP-300HP | Mercury V6 3.0L | DFI / OptiMax | Select DFI and OptiMax applications |
| 175HP-300HP | Mercury Pro Max | High Performance V6 | Select Pro Max cooling systems |
| 175HP-300HP | Mercury Pro XS | High Performance V6 | Select Pro XS applications |
| 175HP-300HP | Mariner V6 Outboards | EFI & DFI | Equivalent Mercury platform applications |
We also stock Pro Marine thermostat part number 9004P for the same Mercury and Mariner applications.
View Pro Marine Thermostat 9004P
OEM Part Numbers & Cross References
| Type | Part Number |
|---|---|
| Current Mercury OEM Number | 8M0057307 |
| Mercury Cross Reference | 885599 |
| Mercury Cross Reference | 885599002 |
| Mercury Cross Reference | 885599003 |
| Mercury Cross Reference | 885599004 |
| Mercury Cross Reference | 885599005 |
| Mercury Cross Reference | 8855991 |
| Pro Marine Part Number | 9004 |
What This Thermostat is Used For
This thermostat regulates cooling system water flow to help maintain proper engine operating temperature inside compatible Mercury and Mariner V6 outboards.
Proper thermostat operation is important for fuel efficiency, combustion quality, cooling system performance, and long-term engine durability.
A sticking or failed thermostat can contribute to overheating, inconsistent engine temperature, poor idle quality, or improper cooling system operation.
Thermostats are commonly replaced during cooling system maintenance, water pump service, or overheating diagnosis on high-performance Mercury outboards.
Key Features and Benefits
- Pro Marine replacement 130°F marine thermostat
- Fits select Mercury and Mariner 175HP-300HP V6 outboards
- Compatible with EFI, DFI, OptiMax, Pro Max, and Pro XS applications
- Replaces Mercury OEM 8M0057307 and 885599 series
- Supports proper engine operating temperature
- Helps maintain cooling system efficiency
- Designed for high-performance marine applications
- Excellent replacement for worn or sticking thermostats
Thermostat Details
- Brand: Pro Marine
- Part Number: 9004
- Temperature Rating: 130°F
- OEM Reference: 8M0057307
- Cross References: 885599, 885599002, 885599003, 885599004, 885599005, 8855991
- Applications: Mercury & Mariner 175HP-300HP V6 Outboards
- Engine Families: 2.5L & 3.0L V6
- Compatible Systems: EFI, DFI, OptiMax, Pro Max, Pro XS
- System: Cooling System
- Use: Engine temperature regulation
FAQ
What engines does this thermostat fit?
This thermostat fits select Mercury and Mariner 175HP-300HP EFI, DFI, OptiMax, Pro Max, and Pro XS V6 outboards using the listed OEM references.
What temperature is this thermostat?
This is a 130°F marine thermostat.
What OEM numbers does this replace?
This thermostat replaces Mercury OEM number 8M0057307 along with the 885599 series thermostat numbers.
When should a thermostat be replaced?
Thermostats are commonly replaced during cooling system maintenance, overheating diagnosis, or water pump service.
Do you offer another version of this thermostat?
Yes. We also stock alternate Pro Marine thermostat part number 9004P for compatible applications.
Dealer Discounts & Store Policies
Dealer / Marine Industry Discounts
Are you a marine dealer, technician, boat builder, or industry professional? We offer dealer pricing for qualified marine businesses.
Shipping Policy
- Free shipping on orders over $100 continental U.S.
- Orders ship via UPS, USPS, and FedEx.
- Orders received before 5:30 PM EST ship the same business day.
- Typical delivery time is 1–5 business days.
30-Day Return Policy
- Returns accepted within 30 days of delivery.
- Cooling system parts should be installed only after proper diagnosis and inspection.
- Items must be new, unused, and in original packaging.
- Return authorization is required before sending items back.
Need help with a return or order question?
Contact Us
Phone: 941-721-3000
Searchable Terms
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8M0057307
885599
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885599004
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8855991
8M0142688
8M6000634
8M6000637
889659002
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2964515
2964520
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3912520
4587610
4587615
4587620
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822253A20
822253T20
