United States

Environmental Protection

Agency

Office of Mobile Sources

Air and Radiation

Emission Standards for New

Spark-Ignition Marine Engines

Information for the Marine Industry

The cooperative efforts of marine engine manufacturers has

led the U.S. Environmental Protection Agency (EPA) to issue

cost-effective regulations for achieving an unprecedented 75

percent reduction in hydrocarbon (HC) emissions from new

gasoline marine engines by the year 2025. These emission

standards, which will affect outboard and personal watercraft

engines, will be phased-in over a nine year period beginning in

model year 1998.

Overview

EPA is issuing regulations for the control of exhaust emissions from

new spark-ignition (SI) gasoline marine engines, including outboard

engines, personal watercraft engines, and jet boat engines. Both

domestic and foreign manufacturers producing engines for sale in the

United States are potentially responsible for compliance with these

regulations. Once the program is fully implemented, manufacturers

of these engines must demonstrate to EPA that HC emissions are

reduced by 75 percent from present levels, by testing engines

representative of the product line before sale and after use.

EPA420-F-96-013

August 1996

Environmental

Fact Sheet
HC contributes to ground level ozone which is known to cause a

range of human pulmonary and respiratory health effects, including

chest pain, coughing, and shortness of breath. Controlling emissions

from these engines will help reduce adverse health and welfare

impacts associated with ozone.

Study Indicates need for Action

Until recently, emissions from nonroad engines and vehicles have

been essentially uncontrolled. The Clean Air Act Amendments

(CAA) of 1990, for the first time, granted EPA the authority to

regulate these sources. Under the direction of the CAA, EPA

completed a study of nonroad emissions which concluded that

nonroad HC emissions in total are 10 percent of the urban

summertime inventory of HC from all sources (see Figure 1).

Marine engines in particular contribute significantly to air quality

problems throughout the United States. Of nonroad sources, EPA

determined one of the largest contributors of HC emissions to be

gasoline marine engines. As illustrated in Figure 2, recreational

marine engines are 30 percent of the nonroad portion. With this

finding, the CAA directed EPA to promulgate regulations to control

air pollution from marine engines.

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Highway

 33%

Other

 57%

Total Nonroad

 10%

Figure 1- Urban Summertime Hydrocarbons: All

Sources
Cooperative Efforts from the Marine Industry

This rulemaking is a prime example of EPA and industry working

together cooperatively to introduce regulations that achieve

substantial emission reductions from nonroad engine sources while

providing manufacturers with the flexibility to achieve the required

reductions based on market demand. The resulting standards will

encourage a wide range of new outboard and personal watercraft

(OB/PWC) products. With the input and support from the marine

industry, EPA has developed a program that is not expected to be

overly burdensome or costly in the manufacturing and selling of

these new technologies. Manufacturers will have many options for

achieving compliance, which include converting current OB/PWC

2-stroke engine technology to 4-stroke, direct-injection 2-stroke, or

possibly equipping engines with catalytic converters in some

applications.

Highlights of the Regulations

Unlike sterndrive and inboard (SD/I) gasoline marine engines, the

majority of OB/PWC (including jet boat) engines currently utilize

2-stroke technology that emits high rates of HC exhaust emissions.

Due to the inherent low emissions of SD/I engines, EPA is only

imposing emission standards for OB/PWC engines.

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Emission

Standards

Other Nonroad

Engines

 20%

Recreational

Marine Engines

 30%

Small SparkIgnition Engines

 50%

Figure 2 - Nonroad Sources of Hydrocarbons
The OB/PWC program requires increasing stringent HC control over

the course of a nine-year phase-in period beginning in model year

1998. By the end of the phase-in, each manufacturer must meet an

HC+NOx (oxides of nitrogen) emission standard on a corporate

average basis that represents a 75 percent reduction in HC compared

to unregulated levels. The emission standard allows the manufacturers and the market to determine the best way to achieve the targeted

reductions over time by allowing the manufacturer to decide the type

of control technologies to be applied to each engine family.

Compliance with a corporate average emission standard gives

manufacturers the flexibility to build engines below and above the

emission standard, provided the manufacturer’s overall corporate

average is at or below the standard.

These regulations only affect new gasoline OB/PWC engines sold in

the future, beginning in 1998. The standards do not apply to any

engine or boat already owned.

EPA is finalizing some innovative administrative programs for OB/

PWC appropriately designed in consideration of the unique market

structure and nature of the marine engine industry. The administrative programs are designed to ensure the targeted reductions are met

by making manufacturers responsible for testing engines, reporting

the results to EPA, and demonstrating compliance with the emission

standards.

The pre-production certification program requires all gasoline marine

engine families to be certified by EPA as meeting applicable

emission standards before they are introduced into commerce. EPA

is introducing a proactive approach to quality control for this

industry by requiring manufacturers to be responsible for ensuring

that engines are produced as designed. Manufacturers will comply by

testing engines as they leave the production line, at appropriate

sampling rates, without EPA presence.

The manufacturers will ensure their engines are meeting applicable

emission standards when actually in use by testing a portion of their

fleet each year. EPA has developed an in-use credit program to

provide manufacturers flexibility in addressing potential in-use

noncompliance. EPA is proud to introduce unique, innovate

administrative compliance programs appropriately designed for this

industry.

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Administrative

Programs
With the introduction of new technologies comes the cautious

reaction from consumers regarding the reliability of such engines. To

help ensure the manufacturing of a durable emission system and to

help alleviate potential concerns of consumers, EPA is introducing

warranty requirements that will, in effect, double or triple the

warranty time period for those items related to the emission

characteristics of the engine. Major emission control components

and emission related components will be covered by the consumer

warranty.

While manufacturers in this industry tend not to be “small,” EPA has

taken measures to reduce the burden on those manufacturers with

smaller volume engine families. Manufacturers can feel at ease that

the regulations provide appropriate flexibility, as the testing and

administrative programs have been designed with such smaller

volume families in mind.

The program is designed to provide manufacturers with the utmost

flexibility for finding the lowest cost solutions to meeting the

emission reduction targets. EPA expects the average costs for OB/

PWC engines will increase modestly, that is, an approximate

increase of 10-15 percent per engine, or $700 for the average power

output engine. EPA is confident that consumers will see this as

negligible when compared to the performance advantages to be

enjoyed by the boat owner from these improved engines. The costeffectiveness of the program is estimated at $1000 per ton HC

reduced.

For More Information

EPA encourages additional information be obtained electronically

via the EPA Internet server or via dial-up modem on the Technology

Transfer Network (TTN), an electronic bulletin board system (BBS).

World Wide Web: http://www.epa.gov/OMSWWW

TTN BBS: 919-541-5742 (1200-14400 bps, no parity,

8 data bits, 1 stop bit); voice helpline: 919-541-5384

Information is also available on this rulemaking by calling 313-668-

4333, or writing to:

U.S. Environmental Protection Agency

National Vehicle and Fuel Emissions Laboratory

2565 Plymouth Road

Ann Arbor, Michigan 48105

Small Volume

Engine Families

Cost

Effectiveness

Extended

Warranty

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