Four-stroke gasoline engines have long been a mainstay of the general marine industry. They have succeeded in reducing emissions and increasing fuel efficiency, and they have also been a hit with consumers. In fact, Mercury Marine has seen its four-stroke outboard sales surpass its two-stroke sales. When four-stroke outboard motors were introduced to the market, manufacturers recommended either their own specially formulated oil or an API SG or SL automotive oil. However, because the specific lubrication requirements of automobiles and outboard motors are different, it soon became apparent that four-stroke outboard motors would require their own oil specification. This standard, entitled FC-W, was released by the National Marine Manufacturers Association (NMMA) in August 2004.
New AMSOIL Formula 4-Stroke® Marine Synthetic Motor Oils are premium quality synthetic formulations engineered for the harsh operating conditions of marine environments. They withstand the intense mechanical activity of continuous, high RPM operation to deliver superior viscosity protection. Formula 4-Stroke® Marine Synthetic Motor Oils are specially fortified with a heavy treatment of advanced additives that protect motors against wear, rust and deposits, and they excel in both high horsepower applications and all-day trolling conditions (see four-ball wear chart).
AMSOIL Synthetic 4-Stroke Marine Motor Oil is available in two SAE viscosities: