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Federal Exhaust Emissions Standards for Marine Spark-Ignition Engines and Vehicles


Dataset Excel: 

KEY:  CO = carbon monoxide; g = gram; hr = hour; HC = hydrocarbon; kW = kilowatt; kWh = kilowatt hour; NOx = nitrogen oxide; P = rated power; yr = year. 

a The standards apply to marine spark-ignition outboard, personal watercraft, and jet-boat engines only. Marine compression-ignition engines under 50 hp are covered under the proposed nonroad compression-ignition engine standards. Federal standards are in development for marine compression-ignition engines over 50 hp. 

b The standards for personal watercraft did not go into effect until 1999, although the standard went into effect for outboard engines in 1998. 

c P = the maximum engine power in kilowatts.

d As an example, the standards for an outboard engine of 125 hp (just over 93 kW) would be 149.55 g/kWh in 1998, 123.65 g/kWh in 2000, 97.75 g/kWh in 2002, 72.01 g/kWh in 2004, 46.11 g/kWh in 2006, and 16.54 in 2010.

e Warranty period and useful life are expressed hours or years of operation (unlesss otherwise indicated), whichever comes first.

f A longer useful life in terms of hours must be specified for the engine family if the average service life is longer than the minimum value as described in 40 CFR 1045.103(e)(3). 

g Not-to-exceed emission standards specified in 40 CFR 1045.107 also apply.

h The useful life may not be shorter than: (1) 150 hours of operation; (2) the recommended overhaul interval; or (3) the engine›s mechanical warranty. A longer useful life must be specified in terms of hours if the average service life is longer than the minimum value as described in 40 CFR 1045.105(e)(3).


U.S. Environmental Protection Agency, Office of Transportation and Air Quality, Marine Spark-Ignition Engines and Vehicles: Exhaust Emission Standards, (March 2016, EPA-420-B-16-026), available at as of Dec. 12, 2019.