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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.
888988001
Pro Marine Thermostat Assembly
Aftermarket Yamaha 4.2L V6 Thermostat
This Pro Marine thermostat assembly is an aftermarket replacement for Yamaha OEM part number 6CE-12411-00-00 and Mercury cross reference 8M6012799.
The thermostat regulates engine cooling system temperature to help maintain proper engine operating temperature, fuel efficiency, corrosion protection, and reliable engine performance.
Compatible Applications
| Engine Range | Engine Type | System | Application Notes |
|---|---|---|---|
| Yamaha F225 / LF225 | 4.2L FourStroke V6 | Cooling System | Select models using thermostat 6CE-12411-00-00 |
| Yamaha F250 / LF250 | 4.2L FourStroke V6 | Cooling System | Select offshore and standard rotation applications |
| Yamaha F300 / LF300 | 4.2L FourStroke V6 | Cooling System | Used in compatible offshore cooling systems |
| Yamaha VF250 | V MAX SHO 4.2L | Cooling System | Select SHO cooling system applications |
Mercury OEM number 8M6012799 cross references this Yamaha thermostat for compatible Mercury-branded Yamaha powerhead applications.
Always verify your model number, serial number, and cooling system diagram before ordering thermostats and cooling system components.
OEM Part Numbers & Cross References
| Brand / Type | Part Number |
|---|---|
| Pro Marine | 6CE-12411P |
| Replaces Yamaha OEM | 6CE-12411-00-00 |
| Replaces Mercury OEM | 8M6012799 |
| Alternate Search Format | 6CE124110000 |
OEM and EMP Alternatives
What This Thermostat is Used For
This thermostat is used in compatible Yamaha and Mercury FourStroke cooling systems to regulate engine operating temperature.
The thermostat controls coolant flow through the engine to help the engine warm up properly and maintain consistent operating temperature.
A faulty thermostat may contribute to overheating, improper engine temperature, poor fuel efficiency, or excessive engine wear.
Replacing worn thermostats during cooling system maintenance helps maintain reliable engine performance and cooling system operation.
Key Features and Benefits
- Pro Marine aftermarket thermostat assembly
- Replaces Yamaha thermostat 6CE-12411-00-00
- Fits select Yamaha F225, F250, F300, LF-series, and VF250 models
- Designed for Yamaha 4.2L V6 cooling systems
- Helps maintain proper engine operating temperature
- Supports cooling system performance and engine efficiency
- Aftermarket alternative to OEM Yamaha thermostat
Thermostat Details
- Brand: Pro Marine
- Part Type: Thermostat Assembly
- Pro Marine Part Number: 6CE-12411P
- Replaces OEM: Yamaha 6CE-12411-00-00
- Mercury Cross Reference: 8M6012799
- Application: Yamaha 4.2L V6 Cooling Systems
- System: Cooling System
- Use: Engine temperature regulation
- Quantity Sold: Each
FAQ
What does Pro Marine 6CE-12411P replace?
This thermostat replaces Yamaha OEM thermostat 6CE-12411-00-00 and Mercury thermostat 8M6012799.
What engines does this thermostat fit?
This thermostat fits select Yamaha F225, F250, F300, LF-series, and VF250 4.2L V6 outboards.
What does this thermostat do?
It regulates engine cooling system temperature and coolant flow.
Can a bad thermostat cause overheating?
Yes. A faulty thermostat may restrict coolant flow or prevent proper engine temperature regulation.
Is this an OEM Yamaha thermostat?
No. This is a Pro Marine aftermarket replacement thermostat.
Are OEM and EMP versions available?
Yes. OEM Yamaha and EMP replacement versions are also available.
Should I verify fitment before ordering?
Yes. Yamaha used multiple thermostat configurations depending on model and production range.
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 components should be installed only after confirming correct fitment.
- 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
6CE-12411P, 6CE-12411-00-00, 8M6012799, Pro Marine thermostat, Yamaha thermostat, Yamaha 4.2 thermostat, Yamaha F225 thermostat, Yamaha F250 thermostat, Yamaha F300 thermostat, Yamaha LF250 thermostat, Yamaha LF300 thermostat, Yamaha VF250 thermostat, Mercury thermostat, Mercury 8M6012799, offshore thermostat, cooling system thermostat, FourStroke thermostat
6CE-12411-00-00
8M6012799
854512T
Pro Marine 130°F V6 Outboard Thermostat
Mercury & Mariner 2.5L / 3.0L EFI & DFI Thermostat
The Pro Marine 9004P 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 reliable 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 another Pro Marine replacement thermostat for compatible Mercury and Mariner applications.
View Alternate Pro Marine 130°F Thermostat
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 | 9004P |
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 critical 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: 9004P
- 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 9004 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
9004P, 8M0057307, 885599, 885599002, 885599003, 885599004, 885599005, 8855991, Mercury thermostat, Mercury 130 thermostat, Mercury OptiMax thermostat, Mercury Pro XS thermostat, Mercury Pro Max thermostat, Mercury 2.5L thermostat, Mercury 3.0L thermostat, Mercury V6 thermostat, Mariner thermostat, 130 degree marine thermostat, Pro Marine thermostat
8M0057307
885599
885599002
885599003
885599004
885599005
8855991
884408A08
884408T05
884408T06
878231T2
OEM Mercury Thermostat Cover Kit
Mercury 3.0L EFI / DFI / OptiMax Thermostat Cover Assembly
This OEM Mercury thermostat cover kit is designed for select Mercury and Mariner 3.0L EFI, DFI, OptiMax, and Pro XS V6 outboards.
This cover kit helps restore proper thermostat sealing and cooling system performance on compatible Mercury 3.0L high-performance outboards.
Compatible Applications
| Horsepower Range | Engine Family | Engine Type | Application Notes |
|---|---|---|---|
| 200HP-225HP | Mercury / Mariner 3.0L V6 | EFI | Select 3.0L thermostat cover applications |
| 200HP-300HP | Mercury / Mariner 3.0L V6 | DFI / OptiMax | Select 3.0L DFI and OptiMax cooling systems |
| 225HP-300HP | Mercury Pro XS | 3.0L High Performance V6 | Select Pro XS thermostat cover applications |
This thermostat cover kit is commonly serviced together with the thermostat during cooling system maintenance.
View Pro Marine 130°F Thermostat
We also stock the alternate thermostat version:
View Pro Marine 130°F Thermostat 9004P
OEM Part Numbers & Cross References
| Type | Part Number |
|---|---|
| Mercury OEM Number | 885599A1 |
| Mercury OEM Cross Reference | 858856 |
| Pro Marine Item Number | 9004K |
What This Thermostat Cover Kit is Used For
This Mercury thermostat cover kit is used to secure and seal the thermostat assembly inside compatible Mercury 3.0L V6 outboards.
Proper thermostat cover sealing helps maintain correct cooling system pressure, water flow, and engine operating temperature.
Corrosion, damaged sealing surfaces, stripped hardware, or leaking gaskets can contribute to cooling system leaks and temperature regulation problems.
Thermostat cover kits are commonly replaced during thermostat service, cooling system rebuilds, or overheating diagnosis.
Key Features and Benefits
- OEM Mercury thermostat cover kit
- Fits select Mercury and Mariner 3.0L EFI, DFI, and OptiMax outboards
- Compatible with select Mercury Pro XS 3.0L applications
- Replaces Mercury OEM numbers 885599A1 and 858856
- Helps maintain proper thermostat sealing
- Supports proper cooling system operation
- Excellent replacement for corroded or leaking thermostat covers
- Designed for marine outboard cooling systems
Thermostat Cover Kit Details
- Brand: Mercury Marine
- Part Number: 9004K
- OEM References: 885599A1, 858856
- Applications: Mercury & Mariner 3.0L V6 Outboards
- Compatible Systems: EFI, DFI, OptiMax, Pro XS
- Engine Family: 3.0L V6
- System: Cooling System
- Use: Thermostat sealing and cover service
FAQ
What engines does this thermostat cover kit fit?
This kit fits select Mercury and Mariner 3.0L EFI, DFI, OptiMax, and Pro XS V6 outboards using the listed OEM references.
Is this an OEM Mercury part?
Yes. This is an OEM Mercury thermostat cover kit.
What OEM numbers does this replace?
This thermostat cover kit replaces Mercury OEM numbers 885599A1 and 858856.
Should the thermostat also be replaced during service?
In many cases yes. Thermostat covers and thermostats are commonly serviced together during cooling system maintenance.
What happens if the thermostat cover leaks?
A leaking or damaged thermostat cover can contribute to cooling system pressure loss, water leaks, and improper engine temperature regulation.
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
9004K, 885599A1, 858856, Mercury thermostat cover, Mercury thermostat housing, Mercury OptiMax thermostat cover, Mercury Pro XS thermostat cover, Mercury 3.0L thermostat housing, Mercury V6 thermostat cover, Mariner thermostat cover, thermostat cover kit, OEM Mercury thermostat cover kit, Mercury cooling system parts
885599A1
96233A2