US EPA Marine Emissions Guidelines - 2004 (Adobe Acrobat) Ever wonder what the real rules are for marine engines? These are the federal EPA's guidelines. Courtesy of the US EPA's website.
2003-01-03 Final Regulation Order for Spark-Ignition Marine Engines (Adobe Acrobat) ...And here is the California Air Resource's Board (CARB) rules, including definitions of the different "star" ratings.