Marine engines can and are often used for extended periods at wide-open throttle (up to 6400 rpm on some models), in harsh saltwater, and intense UV sunlight. Then, marine engines sit in storage over the off-season, in many cases without any use. Focusing on these demands, all Mercury Marine Precision Oils and Lubricants are specially engineered for the unique needs of marine engines and rigorously tested to meet our high standards, protecting your outboard and providing many years of engine life.

Mercury Precision Lubricants: Two-stroke

Premium Plus Two-Stroke High-Horsepower Outboard Oil

Specifically formulated with a higher concentration marine additive package to meet the needs of high-horsepower outboards including direct-fuel-injected engines in extreme marine operating conditions. Far exceeds Mercury in-house test standards, which are more stringent than the industry's TC-W3 standard. Cleanest burning, reduces carbon build-up in exhaust system and superior lubrication. Meets all outboard and personal watercraft manufacturers' recommendations for use of TC-W2 and TC-W3 oils in pre-mix or oil-injected 2-cycle applications. Provides warranty protection for Mercury, Mariner, Force and Sport Jet and M2 Jet Drive 2-cycle engines.

OptiMax/DFI 2-Stroke Outboard Oil

A synthetic blend 2-Cycle engine oil specifically formulated and developed to meet the needs of OptiMax and Direct Fuel Injected (DFI) 2-cycle outboard engines.  Provides the maximum protection for OptiMax and DFI engines even under the most extreme operating conditions. Outperforms other oils by combining a carefully modified base stock blend with a synthetic additive package. Minimizes carbon build-up to help maintain engine top end speed and acceleration. Superior lubrication for increased resistance to piston scuffing. Will mix with typical 2-cycle engine oils. Provides warranty protection for Mercury and Mariner OptiMax and DFI outboards.

Premium 2-Cycle Outboard Oil for Low to Mid-Horsepower Outboards

Specifically formulated with a marine additive package to meet the needs of low- to mid-horsepower outboard engines operating under general marine conditions. Exceeds TC-W3 standards. Reduces rust and corrosion of internal components. Meets all outboard and personal watercraft manufacturers' recommendations for use of TC-W2 and TC-W3 oils in pre-mix or oil-injected 2-cycle applications. Provides warranty protection for Mercury, Mariner, Force and Sport Jet 2-cycle engines.

FourStroke Marine Oil: Good, better, best

FC-W FourStroke (25W-40) Oil

Mercury's FourStroke oil technology outperforms automotive oils in marine applications because of its specialized additive package designed for marine engines. 25W40 is recommended for all marine engines.

Things to know about this oil:

• For use in all four-stroke marine engines. This oil is engineering approved for all marine four-stroke applications including outboard, MerCruiser, high performance, sterndrive/inboard. Exceeds all marine industry four-stroke oil requirements including FC-W and FC-W compatibility.
• Outstanding engine and corrosion protection - industry leading strength and viscosity retention and ultimate corrosion and wear protection.
• The most recommended marine oil. More than 5 years of development work by the largest marine manufacturer in the world.

Synthetic Blend 4-Stroke (25W-40) Outboard Oil

A technology specific 25W-40 marine oil formulated for the world's first and only supercharged and inter cooled outboard engine. The unmatched torque and acceleration of the Mercury Verado engine requires maximum protection found in this well-balanced combination of today's highest quality synthetic and mineral base stocks. Mercury 25W-40 Synthetic Blend Outboard Oil meets the stringent marine operational requirements of all of Mercury's new 4 and 6 cylinder models. First in class for all FC-W durability test properties with industry leading internal Marine engine corrosion protection.

25W-40 Synthetic Blend Oil shows significantly better shear stability and volatility, and is higher in viscosity and High Temperature High Shear (HTHS) after shear. The popular competitive formulation uses a fair amount of VM (viscosity modifier) which is subject to shear, while the Mercury oil contains no VM. As a result, the Mercury oil will hold its viscosity far better in high-revving and long-running situations when the engine needs it most. The HTHS after shear follows along with the viscosity stability, which also results in improved bearing protection.

FourStroke (10W-30) Outboard Oil

Specifically formulated and developed to meet the needs of all four-stroke outboard engines. Developed for the rigors of the marine environment. Industry-leading corrosion protection. Features premium-grade synthetic and mineral-based stocks with specially designed marine grade additives not required in automotive oils. Outstanding lubricity for internal engine components to reduce wear, scuffing and scoring. Excellent running quality and long-term reliability. Rigorously tested to guarantee warranty protection for Mercury and Mariner four-stroke outboards.

Synthetic blend FourStroke (10W-30) Outboard Oil

This oil is industry leading in wear, shear and corrosion protection for all Mercury/ Mariner 4-Stroke Outboards (Except for V10) and has advanced corrosion inhibitors to outperform competition and FC-W® standards. It is for use also in all engines requiring the 10W30 viscosity grade. This blend is specially formulated to protect marine engines against harsh marine environments, as well as during intermittent use and off-season storage. 

Full-Synthetic blend FourStroke (10W-30) Outboard Oil

Engineered to extend the life of Mercury 4-stroke outboard engines (except for V10) and keep them running at their peak. A revolutionary dual-grade “super-synthetic” formula resists thermal breakdown when operating at maximum output and high temperatures for extended periods of time, making this Mercury’s toughest and strongest 10W-30 4-stroke oil yet. With 49% more anti-wear additives, 45% more dispersants and 24% more detergents than our high-performing Mercury 10W-30 synthetic blend, it delivers the highest level of protection against corrosion and wear for engines that require 10W-30 oil. This blend is able to deliver better cold starts and maximum viscosity retention across an expansive temperature range. This is critical for maintaining proper engine lubrication.

Mercury Precision Lubricants Gear Lube

Premium Gear Lube - Lower Units for Outboards Below 75 Horsepower

Mercury Marine gear lube outperforms automotive gear oil in marine applications because of its specialized additive package designed for marine gear cases. Continued use of this gear case lubricant will: Provide maximum protection against excessive wear - even in the presence of water prevent corrosion and pitting. Mercury Premium SAE 80W90 Gear Lube is recommended for lower units for outboards below 75 horsepower. Mercury Premium SAE 80W90 Gear Lube should not be mixed with Mercury High-Performance SAE 90 Gear Lube.

High-Performance Gear Lube

Engineered to provide maximum protection for sterndrive and outboard lower units. Exclusive formula is engineered to
provide extended gear life in extreme conditions including high-speed and high-horsepower applications. Extensively tested to provide excellent protection against corrosion and excessive wear. Specifically formulated to help prevent failures due to water entering the gear housing. Extreme pressure synthetic additives protect gears from metal to metal contact. Since no industry-wide standards exist concerning marine gear oils, it is essential to use products such as Mercury High-Performance Gear Lube which has been specifically designed and tested for marine applications. DO NOT mix with Mercury Premium Gear Lube. Provides warranty protection for all Mercury MerCruiser sterndrive and Mercury, Mariner and Force outboard lower units.

Mercury Precision Lubricants Diesel Engine Oil

Diesel (15W-40) Engine Oil

Specifically formulated and developed to meet the needs of all marine diesel engines, including Mercury MerCruiser D-Tronic. Contains a higher additive level than standard fleet oils, providing greater protection. Provides excellent wear tolerance. Provides excellent shear stability to assure stay-in-grade performance. Protects the internal engine components from corrosion and wear. Helps control the formation of sludge and varnish deposits, even in highly stressed applications. Provides warranty protection for Mercury MerCruiser Diesel engines.

Still have questions regarding which oils you need for your engine? Contact one of our trusted dealers through our dealer finder.