From the arb.ca.gov website. SORE = Small Off-Road Engines, CARB = California Air Resources Board
"Examples of equipment with engines that are and are not subject to CARB’s current SORE regulations
SORE used in the following equipment are subject to CARB’s current SORE regulations:
Chainsaws < 45 cc
Edgers
Hedge trimmers
Lawn mowers
Leaf blowers
Log splitters
Portable generators
Pressure washers
Riding mowers
String trimmers
SORE used in the following equipment are not subject to CARB’s current SORE regulations:
Air compressors
Blade-capable brush cutters/clearing saws ≥ 40 cc
Chainsaws ≥ 45 cc
Chippers
Light towers
Pumps ≥ 40 cc
Saws: concrete, masonry, cutoff
Shredders/grinders
Stationary generators
Stump grinders
Welders
Other equipment not subject to SORE regulations:
Equipment with engines that use diesel fuel
Diesel generators
Diesel pressure washers
Diesel pumps
Diesel riding mowers
Stationary equipment
Equipment with LSI engines > 1 liter"