If you are looking at a new outboard-powered boat or considering repowering your current boat, you may be facing what seems a bewildering array of choices.
There are seven well-known outboard brands here in the United States, with several additional manufacturers whose brands are better known outside the country. There are a number of choices in almost every size category, and despite the predictions of some in the industry, you can still choose between two-stroke and four-stroke engines, at least for now.
Here's a look at what's available from the leading manufacturers, where outboard technology stands, and some suggestions for choosing what's right for you.
Multiple-engine installations are common on offshore fishing boats.TWO STROKE VS. FOUR STROKE
The most obvious and significant trend in the outboard industry over the last 10 years has been the emergence of the 4-stroke motor as the dominant configuration. The major manufacturers estimate that as much as 70 percent of new-engine sales are 4-strokes.
Along with the emergence of the 4-stroke has come the modern electronic control module (ECM), used to optimize the combustion process in both 2- and 4-stroke engines. Interesting enough, 2-strokes, which required mixing oil and fuel in a specific proportion to be burned directly, were traditionally more popular. Their mechanical simplicity and light weight made them easy to live with – well, as long as you weren't breathing the blue-tinged exhaust.
As emissions standards began to tighten, new technologies, such as direct fuel injection, were developed. The epitome of the 2-stroke motor today is Evinrude's E-TEC line, which can provide many of the emissions and operating advantages of a 4-stroke motor, but without its mechanical complexity. Evinrude, a division of Bombardier Recreational Products, has essentially absorbed the former Johnson brand. The only model left from Johnson is a simple, carbureted 9.9-horsepower 4-stroke.
Most of the other major brands also still offer 2-stroke motors, in the higher horsepower ranks and all direct-injected. These include the Mercury Optimax, Yamaha HPDI and Nissan TLDI lines.
Five years ago, 4-stroke motors were just making their first significant inroads into the outboard market. Some of the disadvantages of the early 4-strokes, such as heavy weight compared to similar-horsepower 2-strokes and comparatively poor low-speed acceleration, have largely disappeared.
Some boaters still prefer 2-strokes due to their lighter weight and simple mechanical setup.Lightweight designs, incorporating features such as composite material air intakes, along with sophisticated computers to control fuel-delivery schedules and spark advance have leveled the performance field. Some specific markets, such as the bass boat community, still hold tightly to their long-held preference for 2-stroke motors. The saltwater, offshore-fishing community, however, prefers 4-strokes because of their fuel efficiency at high speeds and long-term reliability.
EMISSIONS RULES DRIVE INNOVATION
A great deal of the innovation and success of the 4-stroke motors has been due to increasingly-stringent emissions regulations. The California Air Resources Board (CARB) has led the regulatory charge for the last dozen years.
The federal government has allowed California to set stricter pollution limits than the rest of the nation because of the severity of the pollution problem there. Given the size of the California market for everything from automobiles to lawnmowers to boats, "what is good for California" has typically led to standards we all must live with. Fortunately, we also get the benefits: outboard motors that pollute less and are significantly more fuel-efficient than the old blue-smoke stinkpots we used to lovingly coax into operation.
The CARB standards require outboard manufacturers to offer a product line that meets an average emissions standard across the line. That means they can still offer some of the less "green" motors, as long as they are offset by sales of motors with higher-than-required emissions certification.
It's safe to say that emissions standards are going to continue to tighten, requiring further technical innovation by manufacturers. Current standards are focused on carbon monoxide and oxides of nitrogen. Given the visibility of simple carbon dioxide's contributions to environmental problems, it's not much of a stretch to predict that exhaust product will be the target of tighter rules in the future.
Manufacturers are also innovating to increase fuel efficiency.
David Meeler, product market information manager at Yamaha, says the average boater is "very concerned" about fuel efficiency. "They're still using their boats, but"¦modifying behavior to accept the higher cost of fuel," he explains. "You'll see manufacturers paying more attention to it, developing engines as solutions."
