The design of marine gasoline engines, both two- and four-stroke, have advanced to the point where higher output engines place severe demands on engine lubricants. Likewise, concern over pollution has increased fuel/oil ratios, which, in turn, increase lubricant requirements. To help boaters recognize lubricants that will give the engine life designed-in by marine engine manufacturers, the National Marine Manufacturers Associations (NMMA) longstanding Oil Certification Program was developed for these premium quality lubricants.
The NMMA Marine Oil Certification program consists of two parts, a certification program for oil additive packages and a registration program of oil brands using certified oils.
The registration for marine oil brands is conducted on an annual basis. The TC-W3® symbol signifies a marine oil designed for two-stroke marine engines, the FC-W® symbol signifies a marine oil designed for four-stroke marine engines and the FC-W(CAT)® symbol signifies a marine oil designed to be compatible with four-stroke marine engines that have an exhaust after-treatment catalyst.