40 CFR 90.308 - Lubricating oil and test fuels.
(2) For 2-stroke engines, the fuel/oil mixture ratio must be that which is recommended by the manufacturer.
(b)Test Fuels - Certification.
(1) The manufacturer must use gasoline having the specifications, or substantially equivalent specifications approved by the Administrator, as specified in Table 3 in Appendix A of this subpart for exhaust emission testing of gasoline fueled engines. As an option, manufacturers may use the fuel specified in 40 CFR part 1065, subpart H, for gasoline-fueled engines.
(2) Alternative fuels, such as natural gas, propane, and methanol, used for exhaust emission testing and service accumulation of alternative fuel spark-ignition engines must be representative of commercially available alternative fuels.
(3) Other fuels may be used for testing provided:
(i) They are commercially viable;
(ii) Information acceptable to the Administrator is provided to show that only the designated fuel would be used in customer service; and
(iii) Fuel specifications are approved in writing by the Administrator prior to the start of testing.
(c)Test fuels - service accumulation and aging. Unleaded gasoline representative of commercial gasoline generally available through retail outlets must be used in service accumulation and aging for gasoline-fueled spark-ignition engines. As an alternative, the certification test fuels specified under paragraph (b) of this section may be used for engine service accumulation and aging. Leaded fuel may not be used during service accumulation or aging.