StacksVerified U.S. regulatory reference

40 CFR §1054.650

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
The special provisions in this section apply for engines that will not be governed to control engine speeds consistent with the constant-speed operation reflected by the duty cycles specified in § 1054.505. We refer to these as constant-speed governors in this section. Paragraph (a) of this section also applies for any engines shipped without installed governors.
  1. (a)The representative-testing requirements of 40 CFR 1065.10(c)(1) related to in-use duty cycles do not apply to engines you produce and ship without constant-speed governors if you comply with all the following requirements:
    1. (1)You must have test data showing that the effectiveness of the engine's emission controls over the expected range of in-use operation will be similar to that measured over the specified duty cycle. Alternatively, if your emission controls depend on maintaining a consistent air-fuel ratio, you may demonstrate that the engine is calibrated to maintain a consistent air-fuel ratio over the expected range of in-use operation.
    2. (2)Describe in your application for certification the data and analysis that supports your conclusion.
  2. (b)It is a violation of the tampering provisions in 40 CFR 1068.101(b)(1) to remove a governor from a certified engine unless you recertify the engine in the modified configuration.