40 CFR § 94.214 - Production engines.
Any manufacturer obtaining certification under this part shall supply to the Administrator, upon his/her request, a reasonable number of production engines, as specified by the Administrator. The engines shall be representative of the engines, emission control systems, and fuel systems offered and typical of production engines available for sale or use under the certificate. These engines shall be supplied for testing at such time and place and for such reasonable periods as the Administrator may require. This requirement does not apply for Category 3 engines. Manufacturers of Category 3 engines, however, must allow EPA access to test engines and development engines to the extent necessary to determine that the engine family is in full compliance with the applicable requirements of this part.