Spark-Ignition Marine Engines and Watercraft (SIME/SIMW)

This page last reviewed April 22, 2016


image of boat

ARB's recreational marine engine program is an important new element in ARB's efforts to improve air quality through reductions of hydrocarbon (HC) and oxides of nitrogen (NOx) emissions. Regulations have been adopted for certain marine vessels and regulations have been proposed for other spark-ignition engines used in boats for propulsion. Commercial marine engines are covered under the Commercial Marine Vessel webpage. Spark-ignition auxiliary marine engines (power generators, winches, or auxiliary propulsion engines for sail boats) are defined as small off-road spark-ignition engines (below 25 horsepower) or large off-road spark-ignition engines (25 horsepower and greater) depending on their size. Compression-ignition auxiliary and propulsion marine engines under 50 horsepower are defined as off-road diesel (compression-ignition) engines.

Latest Update: February 8, 2016
  • The Office of Administrative Law has approved the SIMW rulemaking and filed it with the Secretary of State on February 8, 2016. You can view the official documentation here.

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Formal Regulatory Documents

Component and Engine Certifications


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Related Links


Application Template


Off-Road Certification Database

Watercraft Evaporative Certification

Please email certification documents to:

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If you are interested in receiving updates and public annoucements regarding ARB's SIME/SIMW regulatory programs, please click on the link in the left margin labeled "Join the SIME/SIMW E-Mail List" and enter your contact information.

SIME/SIMW Emissions Rulemaking Contacts

  • Exhaust Emissions Lead:  Jeff Lowry (626) 575-6841
  • Evaporative Emission Component Certification:  Michele Dunlop (916) 323-8971