STATE OF CALIFORNIA MOTOR VEHICLE CODE 27156
NOTE: [Bold and all capital letters added for emphasis here]
(Re: Tier 1 and Tier 2 motors, including leafblowers manufactured in or after 1995, which may not be modified for alternate fuel use, according to this code)
These will have two easily identifiable and visible screws towards the top of the machine, surrounded by a raised metal edge, or housing. These are different from machines produced earlier than 1995, where the two screws are exposed. They may also have a manufacturers Tier 1 or Tier 2 white rectangular sticker with several lines of black print, though it may have been removed.
SECTION 27156. . .
(c) No person shall install, sell, offer for sale, or advertise any device, apparatus, or mechanism intended for use with, or as a part of, any required motor vehicle pollution control device or system which alters or modifies the original design or performance of any such motor vehicle pollution control device or system.
(d) If the court finds that a person has willfully violated this section, the court shall impose the maximum fine that may be imposed in the case, and no part of the fine may be suspended.
(e) "Willfully," as used in this section, has the same meaning as the meaning of that word prescribed in Section 7 of the Penal Code.
[Penal Code, Section 7: the word "willfully," when applied to the intent with which an act is done or omitted, implies simply a purpose or willingness to commit the act, or make the omission referred to. It does not require any intent to violate law, or to injure another, or to acquire any advantage.]
(f) No person shall operate a vehicle after notice by a traffic officer that the vehicle is not equipped with the required certified motor vehicle pollution control device correctly installed in operating condition, except as may be necessary to return the vehicle to the residence or place of business of the owner or driver or to a garage, until the vehicle has been properly equipped with such a device.
(g) The notice to appear issued or complaint filed for a violation of this section shall require that the person to whom the notice to appear is issued or against whom the complaint is filed produce proof of correction pursuant to Section 40150 or proof of exemption pursuant to Section 4000.1 or 4000.2.