Specifications for two stroke oil are as follows.
- NMMA TC-W3 – two cycle water-cooled, third generation. TC-W3 obsoletes TC-W & TC-WII. Oils with this spec do not use metal based additives and are ashless. This is an outboard-specific spec -- most mopeds will not use this kind of oil.
- API TC – only API spec established for two cycle engines. It regulates lubricity, detergency, ash content and pre-ignition. Oils with this spec are typically using metal-based, ash-producing additives.
- JASO FA – original spec established regulating lubricity, detergency, initial torque, exhaust smoke and exhaust system blocking (obsolete)
- JASO FB – increased lubricity, detergency, exhaust smoke and exhaust system blocking requirements over FA.
- JASO FC – lubricity and initial torque requirements same as FB, however far higher detergency, exhaust smoke and exhaust system blocking requirements over FB.
- JASO FD – same as FC with far higher detergency requirement.
- ISO-L-EGB – same tests and requirements as JASO FB.
- ISO-L-EGC – same tests and slightly higher detergency requirements (piston varnish) as JASO FC.
- ISO-L-EGD – same tests and requirements as JASO FD.
NMMA: National Marine Manufacturers Association (NMMA) -- based in the USA.
API: American Petroleum Institute -- based in the USA
JASO: Japanese Automobile Standards Organization -- based in Japan
ISO: International Standards Organization -- based in Europe
- Lubricity: oil reduces friction and wear by serving as a layer of protection between moving parts.
- Dispersant: good oil will hold damaging particles like dirt, metal, carbon, sludge and varnish and suspend them in the oil itself, so they can be removed by the oil filter. Other wise those particles would settle to the bottom of the engine and be recirculated through the engine.
- Coolant: even in liquid cooled engines oil dissipates heat away from hot spots inside the engine that coolant passages do not reach. Motorcycle clutches and transmissions rely on oil to regulate temperatures.
- Protection: prevents the internal metals from damage due to oxidation and corrosion.
- Detergent: Clean engine internals. Prevent rings from sticking in the piston lands and deposits from forming on the valves
These specs are established by different governing bodies located in various parts of the world. They all serve the same purpose: to give consumers a quantifiable way to measure the quality of two stroke oil. What does all this mean for your snowmobile, dirt bike or PWC? Most OEM two stroke oils fall in either the JASO FB/ISO-L-EGB (Good) or JASO FC/ISO-L-EGC/API TC (Better) category, although the container and the owners manual will never actually list an oil spec. OEM’s prefer just to recommend their private label product and tell you there is no known equivalent. (It is easy not to have a "known" equivalent if you do not look for one.) The toughest spec currently obtainable for two stroke oil is JASO FD/ISO-L-EGD. Any oil listing this rating is preferred for a snowmobile, dirt bike or PWC. Common sense should tell you that using an oil (including OEM oil) that does not list a rating usually means it does not obtain these ratings, otherwise why would they not want to list it on their product?
Under the Moss-Magnuson Warranty Act, it is illegal for any manufacturer to require the exclusive use of their private label product to keep their warranty valid. If a manufacturer indicates only their private label brand will satisfy warranty requirements, they must do one of two things:
- Obtain written approval from the Federal Trade Commission that no other product except their brand will work (currently, no manufacturer has done so), or
- They must make the product available to you at no cost