AMSOIL 10W-30 Marine Motor Oil

Amsoil Synthetic 4-Stroke Marine 10W-30 Motor Oil

Amsoil synthetic 4 stroke 10w-30 marine outboard oil is for use in 4-stroke gasoline fueled engines in marine applications.

Amsoil synthetic 4 stroke 10w-30 marine outboard oil offers unsurpassed wear protection, viscosity stability, low volatility and excellent rust protection. NMMA FC-W approved and “warranty certified”. For use in 4-stroke outboard and marine inboard engines. Also excellent for personal watercraft.

AMSOIL Formula 4-Stroke® Marine Synthetic 10w-30 Motor Oil is a premium-quality synthetic formulation engineered for the harsh operating conditions of marine environments. It withstands the intense mechanical action of continuous, high-rpm operation to deliver superior viscosity protection. Formula 4-Stroke Marine Synthetic Motor Oil is specially fortified with a heavy treatment of advanced additives that protect motors against wear, rust and deposits. It excels in high-horsepower applications and all-day trolling conditions.

NMMA Certified
Formula 4-Stroke Marine Synthetic Motor 10w-30 Oil is certified by the National Marine Manufacturers Association (NMMA) for use in four-stroke outboard motors. This high-quality oil demonstrates outstanding performance and meets the NMMA FC-W Catalyst Compatible specification requirements.

  • NMMA Registration #FC-00358P 10W-30

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Superior Protection Against Engine Wear
Marine engines operate under high loads and rpm for extended periods of time, causing traditional automotive oils to break down and lose viscosity. To ensure protection and long-term durability, the NMMA introduced the FC-W Catalyst Compatible standard, which is backward-compatible with the recognized requirements of the FC-W standard. AMSOIL Formula 4-Stroke 10w-30 Marine Synthetic Motor Oil meets the FC-W and FC-W Catalyst Compatible shear stability requirements, outperforming competitive oils to deliver a superior lubricating film. Formula 4-Stroke Synthetic Oil contains robust anti-wear additives that further reduce wear in metal-to-metal contact regions.

Excellent Anti-Rust Performance
Marine engines are prone to rust, leading to uncontrolled wear and premature engine failure. Good rust protection is not natural to motor oil; it comes only by design. Formula 4-Stroke 10w-30 Marine Synthetic Motor Oil is fortified with a special anti-rust agent, even more than required to pass stringent NMMA FC-W and FC-W Catalyst Compatible anti-rust testing.

AMSOIL Formula 4-Stroke 10w-30 Marine Synthetic Motor Oil is recommended for gasoline-fueled four-stroke outboard, inboard, inboard/outboard (I/O) and personal watercraft motors. Use the appropriate viscosity grade where specified in the following:

Honda®, Mercury®, Yamaha®, Johnson®/Evinrude®, Bombardier/BRP®, Suzuki®, Nissan®, Tohatsu®, OMC®, Volvo Penta®, Mercruiser®, Chevrolet®, Ford®

Note: AMSOIL Formula 4-Stroke Marine Synthetic 10W-30 is recommended for use in place of 5W-30 as specified by Honda®.

NMMA FC-W Catalyst Compatible • API SM

Service Life

  • Four-stroke outboard motors and personal watercraft applications: Due to potential fuel dilution or water contamination, change oil at the engine or watercraft manufacturer-recommended interval.
  • Inboard and I/O applications: Change oil at two times the engine manufacturer recommended interval or one year, whichever comes first.

AMSOIL Formula 4-Stroke Marine 10w-30 Synthetic Motor Oil is compatible with conventional and synthetic motor oils. Mixing AMSOIL motor oils with other oils, however, will shorten the oil’s life expectancy and reduce the performance benefits. AMSOIL does not support extended drain intervals where oils have been mixed.

Aftermarket oil additives are not recommended for use with AMSOIL motor oils.

AMSOIL products are backed by a Limited Liability Warranty. For complete information visit

This product is not expected to cause health concerns when used for the intended application and according to the recommendations in the Material Safety Data Sheet (MSDS). USA and Canada (M)SDS are available upon request at 715-392-7101 or on the AMSOIL Website. Keep Out of Reach of Children. Recycle used oil and bottle.

For detailed typical technical properties, download the product data bulletin.

WCT Packaging Information
Code Package Size Unit of Measure Product
WCTQT (WCTQT-EA) Quart Each Amsoil Formula 4-Stroke Marine 10W-30 Synthetic Motor Oil
WCTQT (WCTQT-CA) Quart Case of 12 Amsoil Formula 4-Stroke Marine 10W-30 Synthetic Motor Oil
WCT30 (WCT30-EA) 30-Gallon Drum Each Formula 4-Stroke Marine 10W-30 Synthetic Motor Oil
WCT55 (WCT55-EA) 55-Gallon Drum Each Amsoil Formula 4-Stroke Marine 10W-30 Synthetic Motor Oil