Yamaha LUB-10W30-FC-12: Yamalube 4M is a mineral-based four-stroke outboard engine oil that’s an approved NMMA FC-W formulation specifically for use in the harsh marine environment.The FC-W rating, which sets the minimum standard for outboard engine lubrication, corrosion protection, and resistance to potentially harmful effects of oil dilution caused by fuel, provides critical assurance that your outboard’s oil meets the minimum.