Section 1045.401 - What testing requirements apply to my engines that have gone into service?(a) We may perform in-use testing of any engines subject to the standards of this part. If you produce outboard or personal watercraft engines that are subject to the requirements of this part, you must test them as described in this subpart. The testing requirements described in this subpart do not apply to sterndrive/inboard engines. This generally involves testing engines in the field or removing them for measurement in a laboratory.(b) We may approve an alternate plan for showing that in-use engines comply with the requirements of this part if one of the following is true: (1) You produce 200 or fewer engines per year in the selected engine family.(2) You identify a unique aspect of your engine applications that keeps you from doing the required in-use testing.(c) We may void your certificate of conformity for an engine family if you do not meet your obligations under this part.(d) Independent of your responsibility to test in-use engines, we may choose at any time to do our own testing of your in-use engines.(e) If in-use testing shows that engines fail to meet emission standards or other requirements of this part, we may pursue a recall or other remedy as allowed by the Clean Air Act (see § 1045.415 ).