Personal water craft: Encyclopedia II - Personal water craft - Emissions

Personal water craft - Emissions

Before 1990, personal water craft emissions were unregulated in the United States. Many were powered by two-stroke cycle engines, which are smaller and lighter than four-stroke cycle engines but much more polluting. Simple two-stroke engines are lubricated on a "total loss" method, mixing lubricating oil with their fuel; they are estimated to exhaust in excess of 25% of their fuel and oil unburned, in addition to the products of incomplete and complete combustion.

The 1990 amendments to the Clean Air Act allowed the U.S. Environmental Protection Agency to begin regulating personal water craft and other off-road internal combustion engines. The agency began a dialog with manufacturers in 1991, resulting in regulations that were enacted in 1996. These regulations, set to phase in between 1998 and 2006, are averaging standards, allowing manufacturers to offset more polluting engines in their range by selling other engines that exceed the standard. The U.S. State of California has adopted more stringent regulations than the federal standard.

To meet these regulations, manufacturers have adopted a variety of improvements, including increased usage of four-stroke engines, the use of direct injection for two-strokes, and the use of catalytic converters and other pollution-curbing measures which overall have reduced emissions by approximately 75% compared to pre-regulation models.

In some areas, only new personal watercraft that meet the current regulations are permitted; an example is Lake Tahoe.

Environmental groups such as the Surfrider Foundation and the Bluewater Network claim that more rapid progress could be made, and that the large numbers of older watercraft in use continue to emit substantial pollution.

Against this, industry groups such as the Personal Watercraft Industry Association point out that environmental groups continue to cite pollution levels of pre-regulation watercraft and ignore the improvements made to newer models; and furthermore, that the personal watercraft is unfairly singled out when they are no more polluting than other powered boats.

Adapted from the Wikipedia article "Emissions", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki