Genuine Mercury Head Gasket 40-60 HP 4 Stroke 8M0118179

Genuine Mercury Marine OEM Engine Components

Genuine Mercury 8M0118179 Cylinder Head Gasket for 35-60 HP 4-Stroke Outboards

The Genuine Mercury 8M0118179 Cylinder Head Gasket is an original equipment manufacturer (OEM) replacement for select Mercury 35, 40, 50, and 60 HP 4-cylinder 4-stroke outboard engines. Compatible applications include specified carbureted and EFI engines, along with certain EFI Jet, SeaPro, APX, Formula 60, and 60R EFI Racing configurations.

This factory replacement gasket provides the sealing interface between the cylinder head and engine block. It helps maintain combustion chamber compression while separating the engine's cooling water and lubrication passages.

Mercury OEM part number 8M0118179 is listed as the replacement for earlier Mercury cylinder head gasket numbers 857081 and 8M0045278.

This genuine Mercury gasket is intended for compatible cylinder head repairs, gasket replacement, and powerhead service where a factory OEM replacement is preferred.

Pro Marine Aftermarket Alternative Available: We also stock Pro Marine 7081 Cylinder Head Gasket for the same listed applications.

Product Information

• Pro Marine Item Number: 857081
• Manufacturer: Mercury Marine
• Brand: Genuine Mercury OEM
• Current OEM Part Number: 8M0118179
• Previous OEM Numbers: 857081, 8M0045278
• Product Type: Cylinder Head Gasket
• Engine Manufacturer: Mercury Marine
• Engine Type: 4-Stroke Outboard
• Engine Configuration: Inline 4 Cylinder
• Primary Horsepower Applications: 40, 50, and 60 HP
• Additional Application: 35 HP EFI Jet
• Fuel Systems: Carbureted and EFI, depending on model
• Additional Engine Families: SeaPro, APX, Formula 60, 60R EFI Racing
• Application: Cylinder Head to Engine Block
• Condition: New
• Aftermarket Alternative: Pro Marine 7081

OEM and Cross Reference Numbers

Genuine Mercury 8M0118179 is the listed factory replacement for the following Mercury cylinder head gasket numbers.

What This Part Is Used For

The Mercury cylinder head gasket seals the joint between the cylinder head and engine block on compatible 4-cylinder 4-stroke outboard engines.

This gasket helps maintain combustion pressure while preventing cooling water and engine oil from leaking between internal engine passages.

Genuine Mercury 8M0118179 is used during cylinder head removal, gasket replacement, and compatible engine repair procedures.

Common Repair Applications

• Mercury 40 HP 4-stroke cylinder head gasket replacement
• Mercury 50 HP carbureted and EFI cylinder head service
• Mercury 60 HP EFI cylinder head repairs
• Compatible Mercury EFI Jet outboard repairs
• Compatible Mercury SeaPro engine repairs
• Mercury 60 HP APX engine service
• Mercury Formula 60 engine repairs
• Mercury 60R EFI Racing cylinder head service
• Repairs involving compression or cooling water leakage
• Compatible Mercury 4-cylinder powerhead rebuilding

Important Fitment Note

Genuine Mercury 8M0118179 is listed for select Mercury 35-60 HP 4-cylinder 4-stroke engines. Not every Mercury engine within this horsepower range uses the same cylinder head gasket.

Mercury produced several engine configurations within these horsepower ranges, including different cylinder counts, carbureted and EFI fuel systems, and specialized Jet, SeaPro, APX, and Racing models.

The 35 HP application shown in the supplied Mercury catalog is specifically a 35 HP EFI Jet 4-cylinder. This does not establish fitment for every Mercury 35 HP outboard.

Verify your complete Mercury engine serial number and the required OEM cylinder head gasket number before ordering.

Compatible Mercury Outboard Applications

The following engine applications are organized from Mercury parts catalog information. Compatibility is determined by the engine configuration and serial number.

EFI Jet, SeaPro, APX and Racing Serial Number Applications

Mercury 40-60 HP Carbureted 4-Cylinder Applications

Mercury 40-60 HP EFI 4-Cylinder Serial Number Fitment

The following serial number ranges are listed for Mercury 40, 50, and 60 HP EFI 4-cylinder engines.

Later-Production Mercury EFI Applications

Pro Marine Aftermarket Cylinder Head Gasket Available

Looking for an aftermarket alternative to the Genuine Mercury factory gasket? Pro Marine USA also stocks the Pro Marine 7081 Cylinder Head Gasket for the same listed Mercury applications.

Pro Marine 7081 - Aftermarket Cylinder Head Gasket

Pro Marine aftermarket replacement cylinder head gasket for compatible Mercury 35-60 HP 4-cylinder 4-stroke outboard engines.

Pro Marine Part: 7081
OEM Cross References: 857081, 8M0045278, 8M0118179
Brand: Pro Marine Aftermarket

View Pro Marine Aftermarket Gasket

Common Symptoms of a Failed Cylinder Head Gasket

A failed cylinder head gasket can allow combustion gases, engine oil, or cooling water to leak between internal engine passages.

Possible symptoms include:

• Loss of compression in one or more cylinders
• Engine overheating
• Cooling water entering the combustion chamber
• Water contamination in engine oil
• Rough idle or engine misfires
• Reduced engine performance
• Difficulty starting
• Combustion gases entering the cooling system
• Visible damage to the original cylinder head gasket

Installation and Service Tips

Replacing a Mercury 4-cylinder cylinder head gasket requires cylinder head removal and inspection of the engine's sealing surfaces.

Follow the Mercury service manual for your exact engine serial number and configuration.

Recommended Installation Practices

• Confirm the complete Mercury engine serial number.
• Verify that the engine uses OEM gasket 8M0118179 or an applicable earlier number.
• Allow the engine to cool before beginning disassembly.
• Follow Mercury's specified cylinder head removal procedure.
• Inspect the cylinder head and engine block sealing surfaces.
• Check for warpage, cracks, corrosion, and other damage.
• Remove old gasket material without damaging sealing surfaces.
• Keep debris out of cylinders, oil passages, and cooling passages.
• Install the new gasket in the correct orientation.
• Follow the manufacturer's specified tightening sequence.
• Use the correct cylinder head fastener torque procedure.
• Replace additional fasteners or seals when required by the service manual.
• Inspect the cooling system for conditions that caused the original gasket failure.
• Check engine operation and cooling performance after reassembly.

Key Features and Benefits

• Genuine Mercury OEM: Factory replacement cylinder head gasket for compatible Mercury 4-stroke outboards.
• Mercury 4-Cylinder Compatibility: Listed for select 35-60 HP engine configurations.
• Carbureted and EFI Applications: Includes specified Mercury 40, 50, and 60 HP 4-cylinder engine families.
• Specialized Mercury Models: Catalog references include EFI Jet, SeaPro, APX, Formula 60, and 60R EFI Racing.
• OEM Part Number 8M0118179: Listed replacement for earlier Mercury 857081 and 8M0045278 numbers.
• Factory Replacement Component: Intended for compatible cylinder head service and repairs.
• Aftermarket Alternative Available: Pro Marine 7081 is stocked separately.
• Dealer Pricing Available: Qualified marine businesses can apply for wholesale pricing.

Frequently Asked Questions

Is Mercury 8M0118179 a Genuine OEM cylinder head gasket?

Yes. Mercury 8M0118179 is a Genuine Mercury Marine OEM cylinder head gasket for compatible 4-cylinder 4-stroke outboards.

Does Mercury 8M0118179 replace 857081?

Yes. Mercury 8M0118179 is the listed replacement for earlier OEM number 857081.

Does Mercury 8M0118179 replace 8M0045278?

Yes. Mercury 8M0045278 is also listed as a previous OEM number for this cylinder head gasket.

Does this head gasket fit Mercury 40 HP 4-stroke engines?

Yes. This gasket is listed for select Mercury 40 HP carbureted and EFI 4-cylinder 4-stroke engines. Confirm the serial number before ordering.

Does this gasket fit Mercury 50 HP EFI outboards?

Yes. Compatible applications include specified Mercury 50 HP EFI 4-cylinder outboards.

Does this gasket fit Mercury 60 HP 4-stroke engines?

Yes. It is listed for select Mercury 60 HP EFI 4-cylinder engines, including certain SeaPro and specialized racing applications.

Does this gasket fit Mercury 35 HP outboards?

The supplied Mercury catalog lists a 35 HP EFI Jet 4-cylinder application. This does not mean the gasket fits every Mercury 35 HP engine.

Is this gasket used on Mercury Formula 60 engines?

Formula 60 appears in the supplied Mercury catalog for serial numbers 1C104574 through 1C782687. Confirm the required gasket using the appropriate parts diagram.

Does this gasket fit Mercury 60R EFI Racing engines?

The supplied catalog includes Mercury 60R EFI Racing models beginning at serial 1C615064. Verify the engine configuration before ordering.

Is there a Pro Marine aftermarket version available?

Yes. Pro Marine USA also offers Pro Marine 7081 as an aftermarket replacement for the same listed applications.

How do I confirm the correct head gasket for my Mercury outboard?

Locate your complete Mercury engine serial number and compare it with the applicable Mercury parts diagram. Confirm that the diagram identifies 8M0118179 or one of its listed earlier OEM numbers.

Dealer Discounts & Store Policies

Wholesale Marine Parts Pricing

Pro Marine USA supplies Genuine Mercury OEM and aftermarket marine engine parts, cylinder head gaskets, internal engine components, rebuild parts, and maintenance products to marine repair shops, dealerships, technicians, and retail customers.

Qualified marine businesses can apply for a Pro Marine dealer account to access wholesale pricing on eligible marine parts.

Apply for Dealer Pricing

Shipping Information

• Free shipping on orders over $100 within the continental United States.
• In-stock orders received before 5:30 PM EST ship the same business day, Monday-Friday.
• Shipping options available through UPS, USPS, and FedEx.
• Typical delivery time is 1-5 business days.

30-Day Return Policy

• Eligible returns are accepted within 30 days.
• Parts must be new, unused, and in original packaging.
• Installed parts are not returnable.
• Return authorization is required before returning merchandise.

Need Help Confirming Mercury Fitment?

If you are unsure whether Genuine Mercury 8M0118179 is the correct cylinder head gasket for your Mercury outboard, contact Pro Marine USA with your engine horsepower and complete serial number.

Contact Pro Marine USA or call 941-721-3000.

Searchable Part Numbers

857081, 8M0118179, 8M0045278, 7081

Searchable Terms

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