CARB (California Air Research Board):

The Exhaust Emissions Star System For Outboard Motors Explained

California's Air Resources Board (CARB) requires all outboard motors sold in the state be festooned with decals showing either one, two or three stars. So what does the Star rating mean?

Motion picture studios aren't the only organizations with a star system. California's Air Resources Board (CARB) requires all outboard motors sold in the state be festooned with decals showing either one, two or three stars. CARB's star system describes exhaust emissions relative to the phase-down requirements in California, running from 2001 to 2008. A single star on the cowling denotes that that particular outboard meets GARB regulations from 2001. Similarly, two stars indicate the motor meets the more stringent requirements tmet by 2004, while an array of three stars means the outboard meets the really stringent 2008 standards. Know that CARB standards for air quality are stricter then the US Environmental Protection Agency. Also, CARB's star system describes exhaust emissions of both two-stroke and four-stroke outboard motors.

One Star - Low Emission: A single star on the engine cowling denotes that a particular outboard meets CARB regulations for 2001, which are equivalent to the 2006 EPA standard. Outboard motors meeting these standards produce 75% fewer exhaust emissions than conventional carbureted two-stroke engines.

Both two and three stars indicate the motor exhaust emissions meets more stringent requirements that are well below EPA certification levels.

Two Stars - Very Low Emission: The Two Star label identifies an engines that meets CARB's 2004 exhaust emission standards, which means  20% fewer emissions than a One Star (Low Emission) engines.

 

Three Stars - Ultra Low Emission: The Three Star label means an outboard motor  that meet CARB's 2008 exhaust emission standards, or 65% fewer emissions than One Star (Low Emission) engines.

While we won't be seeing any stars on traditional carbureted two-strokes, the state-of-the-art, Direct-Injected two strokes (Evinrude's Ficht, Mercury's OptiMax, Yamaha's HPDI and Nissan's TLDI) are all star nominees. So is the current crop of four-strokes, which are proliferating like paparazzi at a star-studded event.