Mercury High Performance 2-Stroke Oil | 8M0078011

Mercury High Performance 2-Stroke Oil | Part 8M0078011

Part Number: 8M0078011
Brand: Mercury Marine / Quicksilver
Official Product Type: High Performance 2-Stroke Engine Oil
Category: Marine Engine Oils & Lubricants

3.78 Liter

What It Does

Mercury High Performance 2-Stroke Oil is a premium engine oil formulated specifically for Mercury 2-stroke outboard engines. It is designed to provide superior lubrication, reduce carbon deposits, and protect engine components under the high-RPM, high-load conditions typical of marine 2-stroke operation. This oil is blended to meet the demands of Mercury’s high-performance 2-stroke outboard lineup and is the OEM-specified lubricant for applicable engines.

2-stroke outboard engines mix oil directly with fuel — either through an oil injection system or pre-mixed in the fuel tank. Using the correct oil specification is critical for engine protection and longevity. Do not substitute with automotive 2-stroke oils or non-marine-rated products.

System

2-stroke engine lubrication — used in the oil injection reservoir (VRO or direct injection systems) or pre-mixed with fuel for carbureted 2-stroke outboards. Confirm the correct application method for your engine in the Mercury owner’s manual before use.

Compatible Applications

Verify the correct oil specification for your engine in the Mercury owner’s manual or service manual. Not all Mercury 2-stroke oils are interchangeable across engine families.

• Mercury 2-stroke outboard engines specifying High Performance 2-Stroke Oil
• Mercury engines with VRO (Variable Ratio Oiling) injection systems
• Pre-mix applications on applicable Mercury 2-stroke outboards
• Confirm by engine model, year, and owner’s manual specification before use

For Mercury OptiMax and DFI direct-injection 2-stroke engines, a different oil specification is required. See related products below.

Related Parts & Oils

Other Mercury 2-stroke oils and related products in our catalog:

• Mercury Premium TC-W3 2-Stroke Oil – 858021KC1 — standard TC-W3 rated oil
• Mercury Premium Plus TC-W3 2-Stroke Oil 32 oz – 858026KC1
• Mercury MerCruiser Quicksilver OptiMax DFI Synthetic Blend 2-Stroke Oil 4L – 8M0230194 — for OptiMax / DFI engines
• Mercury MerCruiser Quicksilver Performance DFI 2-Stroke Synthetic Blend Oil – 8M0230195
• Mercury MerCruiser Quicksilver OptiMax DFI Synthetic Blend 2-Stroke Oil 10L – 8M0230196
• Mercury OptiMax DFI Synthetic Blend 2-Stroke Oil 10L – 8M0230196
• Quicksilver DFI 2-Stroke Marine Engine Oil 208L Drum – 8M0229803

Service Interval

Replenish the oil injection reservoir before it runs dry — running a 2-stroke engine without oil causes immediate and severe engine damage. For pre-mix applications, mix fresh oil with each tank of fuel at the ratio specified in your engine’s owner’s manual. Do not store pre-mixed fuel for extended periods. Replace oil in the injection reservoir if the engine has been stored for a season without use.

Technical FAQ

Can I use this oil in my OptiMax or DFI engine?
No. Mercury OptiMax and DFI direct-injection 2-stroke engines require a specific synthetic blend DFI oil (such as 8M0230194 or 8M0230195). Using standard 2-stroke oil in a DFI engine can cause carbon buildup and injector damage. Always use the oil specified for your engine.

Can I mix this with TC-W3 rated oil?
Mixing different oil types or brands is not recommended. Use one oil consistently and follow the specification in your Mercury owner’s manual. If switching oils, drain the reservoir fully before refilling with the new oil.

What ratio do I use for pre-mix?
The correct pre-mix ratio depends on your engine model and operating conditions. Refer to your Mercury owner’s manual for the specified ratio — typically 50:1 for break-in and normal operation on applicable engines, but this varies. Do not guess the ratio.

Can I use automotive 2-stroke oil instead?
No. Automotive 2-stroke oils are not formulated for the water-cooled, high-RPM demands of marine outboard engines and can cause carbon buildup, plug fouling, and engine damage. Always use a marine-rated 2-stroke oil that meets the specification in your owner’s manual.

Parts Desk Insights

Best use case: Routine oil replenishment for Mercury 2-stroke outboards with VRO injection systems, or pre-mix applications on applicable engines. This is the OEM-specified high-performance oil for Mercury 2-stroke engines that do not use the DFI/OptiMax synthetic blend specification. Order alongside spark plugs and fuel filters for a complete seasonal service.

Common issues:

• Wrong oil for OptiMax / DFI engines — this is the most common ordering mistake. OptiMax and DFI direct-injection engines require a specific synthetic blend DFI oil. Using standard 2-stroke oil in these engines causes carbon buildup and can damage injectors. Always confirm the oil specification for your engine before ordering.
• Running the injection reservoir low or dry — a 2-stroke engine run without oil is destroyed almost instantly. Check the oil reservoir level before every outing and keep a spare quart on board.
• Using the wrong pre-mix ratio — too lean causes engine seizure; too rich causes plug fouling and carbon buildup. Always follow the ratio in the owner’s manual for your specific engine and operating conditions.
• Storing pre-mixed fuel — pre-mixed fuel degrades quickly. Mix only what you need for the outing and use a fuel stabilizer if the engine will sit for more than 30 days.