Seems one can no longer use crude oil straight from the backyard well.
For two-stroke air-cooled gasoline engines with catalytic converters, use unleaded gasoline and a low sulfur, low ashing oil that meets JASO FB or ISO EGB specifications. Don't use outboard motor oil or gasoline

il ratios lower than 33:1.
-- Operator's Manual for Husqvarna's 357XP 359 chainsaws.
From Echo: WARRANTY STATEMENT INCLUDING EPA PHASE 2 CALIFORNIA TIER III EMISSION WARRANTY [anyone know whether Echo uses catalytic onverts?]
"This ECHO two-stroke engine power product is a quality-engineered unit which has been manufactured to exact tolerances to provide superior performance. To help ensure the performance of the unit, it is required to use two-stroke oil which meets the ISO-L-EGD Standard per ISO/CD 13738 and JASO M345/FC/FD Standards. ECHO Power Blend™ Two-Stroke Oil is a premium two-stroke oil specifically formulated to meet ISO-L-EGD (ISO/CD 13738) and JASO M345/FC/FD Standards. The use of two-stroke oils designed for other applications, such as for outboard motors or lawnmowers can result in severe engine damage, and will void your two-stroke engine warranty.
Emission related parts are covered for 2 years regardless of two-stroke oil used, per the statement listed in the EPA or California Emission Defect Warranty Explanation."
Besides buying oil from the equipment dealers, the major oil companies have the specified oils. From Chevron:
"OLOA 9362 – A premium air-cooled two-stroke cycle engine lubricant additive system designed to meet TISI, API TC, JASO FA, FB, FC, ISO EGD and beyond. It is designed for air-cooled two-stroke cycle engine lubricant use in high-performance air-cooled engines in low to severe duty; uses include motorcycles, chain saws, string trimmers, snow and leaf blowers."