Mercury 4-Stroke High Performance Engine Oil 25W-50 | 1 Qt | 8M0078013

Mercury 4-Stroke High Performance Engine Oil 25W-50 | 1 Quart | Part 8M0078013

Part Number: 8M0078013
Full Reference: 92-8M0078013
Brand: Mercury Marine / Quicksilver
Official Product Type: 4-Stroke High Performance Marine Engine Oil
Viscosity: SAE 25W-50
Base: Synthetic blend
Volume: 1 Quart (946 mL)
Certification: NMMA FC-W

What It Does

This is the OEM-specified engine oil for Mercury high-performance and supercharged 4-stroke outboard and sterndrive engines. The SAE 25W-50 viscosity grade is engineered for engines that operate at sustained high RPM and extreme thermal load — conditions where standard 25W-40 or 10W-30 marine oils cannot maintain adequate film strength. The synthetic-blend formula resists viscosity breakdown under heat, protects against wear and corrosion, and keeps engine internals clean over the service interval.

This is not a general-purpose upgrade for standard Mercury FourStroke outboards. It is the factory-specified oil for Verado, Mercury Racing, and high-output MerCruiser applications. Using the wrong viscosity grade in either direction can affect engine protection and may affect warranty coverage.

System

4-stroke engine lubrication system. Used in the crankcase of applicable high-performance Mercury outboard and MerCruiser sterndrive engines. Change at the interval specified in your engine’s owner’s manual or service manual.

Compatible Applications

Always confirm the correct oil viscosity for your engine in the Mercury owner’s manual or service manual before ordering. The 25W-50 grade is not interchangeable with 25W-40 or 10W-30 specifications.

• Mercury Verado supercharged 4-stroke outboards (all displacements)
• Mercury Racing 4-stroke outboards
• Mercury FormulaRace engines
• MerCruiser 525 EFI, 600 SCi, 700 SCi, 850 SCi high-performance sterndrives
• MerCruiser 1350 and 1650 Racing engines
• Any Mercury or MerCruiser engine specifying SAE 25W-50 high-performance marine oil — confirm in your owner’s manual

Specifications

• Viscosity: SAE 25W-50
• Base: Synthetic blend
• Volume: 1 Quart (946 mL)
• Certification: NMMA FC-W (meets marine engine manufacturer warranty requirements)
• Operation: Wax-element, spring-loaded valve

Related Parts

Commonly ordered together for a complete high-performance engine oil service:

• Mercury MerCruiser Quicksilver High Performance Oil Filter 858004K — the correct high-performance oil filter for applicable engines
• Mercury MerCruiser Quicksilver Oil Filter 822626Q15
• Mercury MerCruiser Quicksilver Oil Filter 8M0116378
• Mercury 4-Stroke Marine Engine Oil – 25W-40, 1L | 8M0078639 — standard FourStroke viscosity (not for Verado/Racing)
• Mercury 4-Stroke Marine Engine Oil – 25W-40, 4L | 8M0078640
• Mercury 4-Stroke Full Synthetic Marine Engine Oil – 25W-40, 1L | 8M0078641
• Mercury 4-Stroke Synthetic Blend Engine Oil – 25W-40, 4L | 8M0078642

Service Interval

Change engine oil and filter every 100 hours or annually, whichever comes first — or per the interval specified in your engine’s owner’s manual. High-performance and supercharged engines operate under greater thermal stress than standard outboards and should not exceed the recommended change interval. Always replace the oil filter at every oil change.

Installation Notes

• Confirm the correct oil viscosity (25W-50) is specified for your engine in the owner’s manual before use
• Replace the oil filter at every oil change — use the filter specified for your engine model
• Warm the engine before draining to ensure full oil evacuation
• Check the oil level after filling and again after the first run to confirm no leaks
• Dispose of used oil responsibly — do not discharge into the water

Technical FAQ

Can I use this oil in a standard Mercury FourStroke outboard?
No. Standard Mercury FourStroke outboards (non-Verado, non-Racing) typically specify 25W-40 or 10W-30. Using 25W-50 in an engine that calls for a lighter viscosity can affect oil flow at startup and is not recommended. Always use the viscosity specified in your owner’s manual.

Is this the same as Mercury’s standard 4-stroke marine oil?
No. The 25W-50 high-performance formula uses a different viscosity grade and additive package than the standard 25W-40 marine oil. They are not interchangeable.

Do I need a specific oil filter with this oil?
Yes. Use the oil filter specified for your engine model. For most high-performance Mercury applications, the Mercury High Performance Oil Filter 858004K is the correct filter. Confirm by your engine model and serial number.

Can I mix this with another brand of 25W-50 marine oil?
Mixing oil brands is not recommended. If switching oils, drain the crankcase fully before refilling. For warranty-covered engines, use the OEM-specified Mercury oil.

Parts Desk Insights

Best use case: Routine oil changes on Mercury Verado supercharged outboards, Mercury Racing engines, and high-output MerCruiser sterndrives that specify SAE 25W-50. Order alongside the correct high-performance oil filter so the full service can be completed in one visit. At 1 quart per bottle, most Verado and high-performance MerCruiser applications require multiple quarts — confirm the crankcase capacity in your service manual before ordering.

Common issues:

• Ordering this oil for a standard FourStroke outboard — the most common mistake. “High performance” does not mean better for every engine. This 25W-50 grade is specifically for supercharged and racing applications. Standard Mercury FourStroke outboards use 25W-40 or 10W-30. Using the wrong viscosity can affect engine protection and warranty coverage.
• Not ordering enough quarts — high-performance and supercharged engines have larger crankcase capacities than standard outboards. Check the service manual for your engine’s oil capacity before ordering — a single quart is rarely sufficient for a full oil change.
• Using the wrong oil filter — high-performance engines require the correct filter for their application. Confirm the filter part number for your engine model before ordering.
• Exceeding the service interval — high-performance engines are harder on oil than standard outboards. Do not extend oil change intervals beyond the manufacturer’s specification.