Short answer
ISO-L-EGD is the highest of three ISO quality grades for two-stroke gasoline engine oils, alongside EGB and EGC. The grades are classified in ISO 6743-15, and the requirements are set out in ISO 13738. They are closely related to the JASO M345 grades FB, FC and FD, with ISO adding its own detergency evaluation.
What ISO 13738 covers
ISO 13738 specifies requirements for oils used in two-stroke spark-ignition gasoline engines with crankcase scavenging, in transportation, leisure and utility applications. The standard’s own examples are motorcycles, snowmobiles and chainsaws. The current edition was published in 2011 and replaced the 2000 edition.
The letter code reads as a classification: “L” for lubricants, “E” for internal combustion engine oils, “G” for gasoline two-stroke, and the last letter for the quality grade. EGB is the entry grade, EGC the middle grade and EGD the highest.
How the ISO grades relate to JASO
The ISO grades were built on the JASO M345 test methods for lubricity, initial torque, detergency, exhaust smoke and exhaust system blocking. EGB, EGC and EGD broadly line up with JASO FB, FC and FD.
They are not identical claims, though. The ISO grades include their own detergency and piston-cleanliness evaluation, so an oil labeled JASO FD and an oil labeled ISO-L-EGD have each been judged against their own document. Many two-stroke oils list both, and some equipment manuals list either one as acceptable.
Outboards and other exclusions
ISO 13738 includes supplementary information about outboard motors in an annex, but water-cooled two-stroke outboards are normally specified to NMMA TC-W3 by their manufacturers. If the outboard manual calls for TC-W3, that is the category to look for.
Direct-injection two-stroke engines can also carry their own oil requirements from the engine maker, which may go beyond any general grade.
Using the grade when you buy oil
If a chainsaw, trimmer or motorcycle manual lists ISO-L-EGD, look for EGD on the label or in the product data. If the manual lists ISO-L-EGC or JASO FC, an EGD oil meets a higher grade, but any brand-specific approval in the manual still applies. The fuel-to-oil ratio is set by the engine maker and is separate from the oil grade.
Frequently asked questions
Is ISO-L-EGD the same as JASO FD?
They are closely related and use the same family of test methods, but ISO adds its own detergency and piston-cleanliness evaluation. Treat them as separate claims and check which one your manual lists.
Where would I see ISO-L-EGD required?
Two-stroke motorcycles, snowmobiles, chainsaws and other handheld equipment manuals often list ISO-L-EGD or EGC, sometimes alongside a JASO grade.
Does ISO-L-EGD apply to four-stroke engines?
No. It is a two-stroke gasoline engine oil grade. Four-stroke motorcycle oils use categories such as JASO MA and API service categories.
General maintenance information. Always follow your vehicle or equipment manufacturer’s requirements and the current product data. Questions? Email [email protected].