United States

Environmental Protection

Agency

Office of Mobile Sources

Air and Radiation

Emission Standards for New

Gasoline Marine Engines

Working cooperatively with the marine industry, the Environmental Protection Agency (EPA) is issuing regulations that will

bring forth a new generation of marine engines featuring

cleaner technology and providing better engine performance

to boat owners. Controlling exhaust emissions from new

gasoline spark-ignition (SI ) marine engines will result in an

unprecedented 75 percent reduction in hydrocarbon (HC)

emissions from these engines by the year 2025.

Emissions from Marine Engines

Because states are finding it increasingly difficult to maintain the

quality of air citizens have come to need and expect, efforts to

improve air quality throughout the nation are shifting focus to

controlling pollution from sources other than on-highway vehicles

and engines. Until recently, emissions from nonroad engines and

vehicles have been essentially uncontrolled. The results of a study

conducted by EPA, however, proved the need for control of air

pollution to reach into the nonroad engine and vehicle arena.

Of nonroad sources, EPA has determined that gasoline marine

engines are one of the largest average contributors of HC emissions.

As illustrated in Figure 1, of all categories of nonroad engines,

recreational marine engines contribute the second highest average

level of HC exhaust emissions. Only small gasoline engines used in

lawn and garden equipment emit higher levels on average.

EPA420-F-96-012

August 1996

Environmental

Fact Sheet
New Emission Standards

Established

The gasoline marine final rule, published

in August 1996, establishes emission

standards for new SI gasoline marine

engines. Covered by the rule are

outboard engines and gasoline marine

engines used in personal watercraft and

jet boat applications.

Emission standards are not set for

sterndrive and inboard engines due to the

inherently clean nature that the

technology of these engines provide.

Manufacturers may begin introducing

these new, clean technology engines as

early as 1997. Boat engines currently inuse are not affected by this regulation.

The statistics in Figure 1, however,

include some areas in which marine

engines are not in use because there are

no nearby lakes or waters. Marine

engines contribute higher levels than

reflected by this average for areas in

which marine engines are used.

Depending on the specific area, the

contribution may be in excess of ten

percent of the total HC inventory, not

just of nonroad sources.

Nonroad sources as a whole on average

contribute ten percent to average HC

inventories. HC contributes to ground

level ozone which is known to cause

irritation to the respiratory system.

Controlling emissions from these

engines will help reduce adverse health

and welfare impacts associated with

ozone.

- 2 -

Figure 1 - Nonroad Sources of Hydrocarbons

Other Nonroad

Engines

 20%

Recreational

Marine Engines

 30%

Small SparkIgnition Engines

 50%
Cleaner and Better

Performing Engines

The new generation of outboard and

personal watercraft (OB/PWC) marine

engines will be over 75 percent cleaner

than current marine engine technology.

That is, once the program is fully

implemented, hydrocarbon emissions

from these engines are expected to be

reduced by over 75 percent from present

levels. Since the reduction in the

inventory depends on sales of these

newer technology engines, EPA expects

to achieve this reduction in HC

emissions from marine engines by the

year 2025. EPA expects a 50 percent

reduction to occur by the year 2020.

In addition to being more environmentally friendly, the new OB/PWC engine

technology will provide boaters with

many performance advantages. The

engines will generally provide easier

starting, faster acceleration, quicker

throttle response, and a reduction in

smoke, fumes and noise. Significant

improvements in fuel economy could

provide hundreds of dollars in fuel

savings. Furthermore, the new fuel

systems and engine designs will relieve

boaters from the hassle of mixing fuel

and oil. As an added benefit to the boat

owner, the emissions performance of

these new OB/PWC marine engines will

be covered by a three-year or 200 hour

warranty, more than double the warranty

currently provided by most engine

manufacturers.

Flexibility Provided to Engine

Manufacturers

With the cooperative efforts of marine

engine manufacturers, EPA has

developed regulations that are not overly

burdensome or costly to manufacturers

or consumers, while still achieving the

overall pollution reduction goals of the

program. This regulation requires

manufacturers of OB/PWC marine

engines to achieve the appropriate yearly

emission reductions by meeting a

corporate average emission standard

which allows them to build some

engines to emission levels lower than the

emission standard and some engines to

emission levels higher than the standard,

provided the manufacturer’s overall

corporate average is at or below the

standard.

Manufacturers have the flexibility to

develop their own technological

solutions to achieve these results based

on market demand. The result will be a

wide range of new products that this

regulation will encourage. Likely

options for achieving compliance

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.

Responsibility of Current and

Future Boat Owners

Boat owners are in no way responsible

for making modifications to their current

engines to meet the standards or subject

to any penalties as a result of this rule.

- 3 -
Boaters can actively participate in

controlling air pollution from these

sources, however, by adopting a few

simple practices. These practices include

operating only well maintained boats,

limiting full throttle operation,

eliminating unnecessary idling,

following recommended maintenance

schedules, eliminating spillage when

refueling, and properly measuring fuel

and oil if required for a particular

engine. In addition to practicing

environmentally friendly operating

procedures, EPA encourages consumers

to do their part in preventing pollution

by purchasing the cleaner technology

engines.

EPA anticipates the price of the new

technology OB/PWC engines to be

slightly higher than the engines currently

offered, but is confident that consumers

will see this as affordable when

compared to the performance advantages

and improved fuel economy to be

enjoyed by the boat owner from these

improved engines.

Effect on Boat Dealers

As with boat owners, boat dealers are

not responsible for compliance with this

regulation. Boat dealers are encouraged

to be aware of this rule and understand

the technological advancements

expected of the future OB/PWC marine

engines. Dealers will likely find it

advantageous to have the ability to

supply consumers with the performance

advantages and potential fuel economy

savings associated with the new

generation of OB/PWC marine engines.

- 4 -

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 by calling

313-668-4333 or writing to:

U.S. EPA

Office of Mobile Sources

2565 Plymouth Road

Ann Arbor, Michigan 48105