Honda Original Equipment Oil 10W30FCW 1 Gallon – 08232-H99-K4LA1 Marine Engine Oil Meats all National Marine Manufacturers Association standards for FC-W oil. Engine oils blended for marine use are different than those for use in automobiles: Specially formulated with rust and corrosion inhibitors to protect engines in both fresh water and salt water marine environments. Shear-stable formulated helps prevent viscosity breakdown in high load, high rpm conditions, for superior viscosity retention.