Description
Mercury Marine 4-Stroke FC-W 25W-40 Synthetic Blend Engine Oil – 1 Quart (8M0078629)
Mercury OEM marine-grade engine oil engineered to protect and extend the life of your 4-stroke outboard and sterndrive engines. This genuine Mercury 8M0078629 FC-W 25W-40 Synthetic Blend oil delivers reliable lubrication and corrosion resistance in both saltwater and freshwater environments, meeting FC-W marine certification standards for superior performance under high-load, high-RPM conditions.
Key Features & Benefits
Technical Specifications
Compatibility & Fitment
This Mercury FC-W 25W-40 Synthetic Blend oil is recommended for use in a wide range of Mercury and MerCruiser 4-stroke engines, including but not limited to:
Important: Always consult your engine’s owner manual for the final word on oil type and service interval.
Usage Instructions
Why Choose Genuine Mercury OEM Oil?
Using authentic Mercury OEM lubricants helps ensure optimal engine life, proper emissions control, and compliance with warranty requirements. Unlike generic automotive oils, this formula is specifically blended to combat high humidity, foaming, and extended idle periods common in marine environments.
FAQs
Can I mix this oil with other brands?
It is always best to use the same brand and grade of oil for each change. While Mercury FC-W oil is generally compatible with other FC-W certified 4-stroke marine oils, mixing can reduce peak performance benefits.
What is the difference between 25W-40 and 10W-30 marine oil?
The 25W-40 grade is formulated for engines that operate under higher loads and temperatures typically found in marine conditions, providing extra high-temperature film strength. Many Mercury outboards and sterndrives specify 25W-40.
Is this oil safe for use with catalytic converters?
Yes. This oil meets NMMA FC-W and API SM standards and is compatible with modern catalyst-equipped marine engines.
Trust & Authenticity
We are an authorized Mercury Marine dealer. Every bottle of Mercury 8M0078629 we ship is genuine OEM product, factory-sealed for freshness and protection. Buying authentic oil helps safeguard your engine’s performance and warranty.
Related Products & Recommended Add-Ons
Shipping & Returns
Ships fast from our authorized marine parts warehouse. Orders over $99 qualify for free standard shipping (continental US). 30-day return policy on unopened, unused products. See our Shipping & Returns Policy for full details.
- OEM-Approved Quality – Official Mercury product, designed specifically for Mercury and MerCruiser 4-stroke marine engines.
- FC-W Certified – Meets NMMA FC-W® standards for 4-stroke marine engines, ensuring correct shear stability and catalyst compatibility.
- 25W-40 Viscosity Grade – Balanced viscosity for marine engines exposed to fluctuating loads, sustained RPM, and wet environments.
- Synthetic Blend Formula – Combines premium base oils with advanced additives for excellent thermal stability and film strength.
- Enhanced Corrosion Resistance – Formulated to protect internal components against rust and corrosion in salt or fresh water.
- High-Shear Stability – Maintains viscosity under heavy loads and high temperatures typical of marine use.
- Optimal Wear Protection – Guards pistons, bearings, and valve-train components against friction-related wear.
- OEM Warranty Protection – Using genuine Mercury oil helps maintain your engine’s warranty and long-term reliability.
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Specification
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Details
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Brand
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Mercury Marine / Quicksilver
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Part Number
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8M0078629
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Viscosity Grade
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25W-40
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Type
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Synthetic Blend 4-Stroke Engine Oil
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Certification
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NMMA FC-W®, API SM
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Volume
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1 US Quart (946 mL)
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Application
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Marine 4-stroke outboard and sterndrive engines
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Corrosion Resistance
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Enhanced additive package for saltwater & freshwater
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Temperature Range
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Recommended for typical ambient operating conditions –10°F to 120°F (–23°C to 49°C)
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Storage & Shelf Life
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Store sealed in a cool, dry place; shelf life up to 5 years
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Country of Origin
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USA (check packaging for latest origin info)
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- Mercury FourStroke outboards: 40 HP – 300 HP (check model-year owner’s manual)
- Verado 4-cylinder and 6-cylinder models (verify viscosity recommendation)
- MerCruiser gasoline sterndrive engines (4-stroke)
- Other marine gasoline 4-stroke engines where FC-W 25W-40 is specified
- Warm up engine to operating temperature before draining old oil.
- Drain oil completely and replace the oil filter if applicable.
- Refill crankcase with Mercury FC-W 25W-40 Synthetic Blend to the capacity specified in your engine manual.
- Run engine and check for leaks, then re-check oil level and top off if necessary.
- Follow recommended service interval – typically every 100 hours of operation or annually, whichever comes first.