What does the CARB star rating mean and how does it relate to EPA regulations?
CARB emission standards are similar to EPA in that they regulate certain aspects of engine emissions that affect air quality. CARB standards, however, are stricter than Environmental Protection Agency (EPA) standards because they call for an accelerated emissions reduction schedule in California. For example, the 2001 CARB one-star standard is equivalent to the 2006 EPA standard. Most outboard manufacturers choose to certify engines to the CARB two-star and three-star levels because they are well below the EPA standards. EPA “credits” can be earned by manufacturers’ engines that are certified below the EPA certification levels, and those credits can be used to offset negative credits imposed on engines that are certified above the EPA standards. The illustration below explains in further detail what each of the CARB star ratings mean.