For marine applications, catalyst conversion efficiency may be restricted to lower conversion efficiency levels (below 80 percent) due to these temperature concerns. While no catalyst-equipped outboard engine has been introduced to the market, one personal watercraft manufacturer -Yamaha- has introduced a 1999 model year product that is equipped with a catalyst.
Overall, marine engine manufacturers are confident these new engine technologies will be viable and marketable in the long-term. The benefits the technologies offer significant reductions of smoke and noise, easier starting, quick throttle response and low exhaust emissions make them the engines of choice for many consumers. Because of their high confidence level in these new technologies and the technical capabilities these new engine designs provide, engine manufacturers are convinced they can continue to bring innovative new engines to market to meet and even exceed the EPA mandates.
