Due to the nature of two-stroke marine engines, two-stroke oil lubricates the engine parts as it passes through the engine and is then burned along with the fuel. Two-stroke oil is either physically mixed with the fuel or, in the case of direct fuel injection, is combined with the fuel in the combustion chamber. This is in contrast to four-stroke engines which have oil sumps circulate the oil by pumping it throughout the engines.
The long term objectives of the two-stroke engine industry have been to reduce emissions which contain burned and unburned oil that have passed through the engine, and to develop a quality of oil that reduces the mixture ratio to fuel while extending the life of the engine. That means significantly reduced emissions to satisfy EPA requirements, less warranty problems, and increased customer satisfaction due to engines lasting longer with less maintenance and overhauls.
TC-W3® lubricant, an NMMA-owned trademark, has evolved over the years through much testing and research, and has proven to be the level of quality needed to satisfy the above objectives. And, going a step further, now that two-stroke engines have moved towards higher cylinder temperatures and compressions, this type of lubricant also helps to meet the EPA emissions reductions.
TC-W3® has demonstrated the necessary lubrication performance quality needed for these more demanding cylinder/engine conditions.
The TC-W3® standard is a performance-based qualification program. The requirements include various bench tests for fluidity, miscibility, rust, compatibility, etc., as well as engine tests to evaluate the prevention of ring sticking and carbon buildup on pistons and other engine parts. The engine tests include one Johnson 40 hp, one Johnson 70 hp, and two consecutive Mercury 15 hp tests, all of which are run under severe conditions for 100 hours each. Two additional engine tests are also conducted to ensure a high level of lubricity performance. The testing process is comprehensive and expensive, but worth the outcome for consumers and manufacturers.
Once lubricants have demonstrated the necessary lubrication performance qualities needed for TC-W3® certification testing by NMMA-approved laboratories, NMMA licenses those two-stroke lubricants to be marketed to the public. TC-W3® oils are licensed around the world and are recommended for use by two-stroke engine manufacturers.