Four-stroke engines are still the hottest sellers—but will the new generation of two-strokes create ripples in the market?

As engine technology continues to develop in new directions, boaters thinking of purchasing an outboard face a wide array of options. While the latest offerings of high-powered and fuel efficient four-stroke engine models continue to demand attention, the new generation of direct-injection two-strokes is making big waves as well.

Despite reports that sales of Bombardier’s Evinrude E-Tec two-stroke engines were up more than 100 per cent for the 2006 model year, the outboard market is still predominantly four-stroke. With leading manufacturers such as Mercury, Yamaha, Honda and Suzuki offering a wide range of high-performance engines, four-stroke technology has been running strong since it hit the mainstream in the late 1990s, with solid consumer support.

According to statistics compiled by the Canadian Marine Manufacturers Association (CMMA), Canada averages about 42,000 outboard sales per year. While Sandy Currie, executive director of the CMMA, says sales point to four-stroke engines as the product of choice (and the majority of the market), he cautions there is no way to predict for certain if the market will remain a four-stroke stronghold or if the new direct-injection two-strokes will begin to win more market share.

“It’s fair to say there’s been a substantial manufacturing shift from two-stroke engines to four-strokes…but there are still probably more than a million outboard motors out there, Canada-wide. When those people decide they need to replace their outboards, will they go with two-stroke or four-stroke? No one really knows the answer to that.”

Although it’s been less than a decade since four-stroke marine motors began making an impact with consumers, Honda Marine has been building four-strokes for more than 40 years and was the first manufacturer to introduce a full line of four-stroke outboard motors in the US—“setting a new benchmark for ease of starting, quiet operation, and low emissions,” according to the company’s website.

Historically, however, most recreational boaters opted for the traditional two-stroke motor. When boaters considered the lighter weight, ease of maintenance and lower purchase price of the two-stroke, it seemed the most logical choice. From a manufacturer’s perspective they were ideal as well. “The production costs were a lot lower,” explains Arthur McNeil, the Mercury Marine Canada business development manager for the Atlantic region. Until the year 2000, the two-stroke was pretty much the only engine available.

The traditional two-stroke engine mixes gas with oil. As people gradually became more concerned about pollution, two-stroke motors began to earn a bad reputation for their high emissions. Following the lead of the US Environmental Protection Agency, Environment Canada signed a voluntary agreement with the Canadian Marine Manufacturers Association and the manufacturers themselves in January 2000 to sell cleaner outboards. Manufacturers then began putting their time and money into four-stroke production and a new breed of higher-powered, sleeker models soon hit the outboard market. The biggest beef with the earlier four-stroke models—that they were too heavy and lacked power—began to be a thing of the past.

“The traditional outboard models are being phased out by all manufacturers, with a limited selection of models [two-strokes with no CARB rating] being offered by some in the short term, says Arthur. “The four-stroke outboard offers fuel savings, with smooth, quiet engine operation.” He is quick to point out, however, that direct-injected two-strokes offer similar benefits as the four-strokes—which is why they are such a growing force in today’s outboard motor market.

Still, “consumer demand creates the market,” he says. “Engine models now offered with four-stroke technology include 2 hp to 300 hp with a full selection between. This change of technologies is created by both consumer demand and meeting Environmental Protection Agency (EPA) standards for the US market. The tipping point for four-strokes being more popular over traditional two-strokes was within the past couple of years. Manufacturers have helped to push the balance of technology with rebates, purchase incentives and warranties.”

At the top end, they’re also pushing horsepower: Mercury’s Verado 275 is the biggest of their in-line 6 supercharged four-strokes; Yamaha has the F250 and Honda has the BF225 V6, featuring their Variable Valve Timing and Lift Electronic Control (VTEC) system. Suzuki’s bid for “big dog” status came last May with the announcement of the launch of the DF300, the industry’s first 300 hp V6 four-stroke outboard engine.

In the mid-range and “portable horsepower” range for small to mid-sized boats there are lots of options as well—most carrying a three-star rating for ultra-low emissions from the California Air Resources Board (CARB). Yamaha’s 90, 75, 60 and 50 hp models feature multi-port precision fuel injection, using four independent fuel injectors to deliver the optimal fuel/air mix to each cylinder, boosting acceleration, top-end and fuel economy. Rounding out Yamaha’s four-stroke line-up are the F9.9, F8, F6, F4 and F2.5 models.

Based on technology developed for the Honda Civic car, Honda’s BF90 and BF75 models feature a fuel-efficient and compact four-cylinder, four-carburetor design they claim is more responsive than one large throttle body and long intake-runner design. At the smaller end of Honda’s range is the BF2, a lightweight four-stroke model with a three-star CARB rating.

Mercury’s mid-range four-strokes are designed with a fully filtered air intake to protect internal engine components, as well as Mercury’s SmartCraft Integrated Marine Technology to provide information on fuel usage or warnings of potential problems. All 2006 Mercury 1.6L and 1.7L four-stroke engines are equipped with turn-key starting for consistently easy, fast ignition. They also feature electronic fuel injection along with a rating that exceeds 2008 EPA emissions standards. For smaller craft Mercury has a 2.5 hp four-stroke with a three-star CARB rating. It features a one-piece integrated cylinder block design to provide added reliability by eliminating gaskets and fasteners. This makes the power head much more compact and lightweight.

While it seems the latest in four-stroke technology is exactly what consumers are looking for in the outboard motor market, it’s not so much what the consumer wants as what the manufacturer is supplying that creates the demand, according to Graham White, owner of White Water Marine in Lower Sackville. He agrees that the average recreational boater is concerned about fuel economy and low emissions, but from his 20 years experience in the business he believes the main goal for someone looking to buy an outboard motor is its reliability and ease of maintenance. With that in mind, he decided in late 2006 to drop one of his four-stroke outboard lines and pick up the new line of direct-injection two-stroke engines manufactured by Bombardier Recreational Products Inc. (BRP) instead.

“I do believe we’re going to see a lot more of the direct-injection two-strokes in the years to come,” Graham says. “There are no oil changes, no belts and no valve or throttle linkage adjustments—fewer moving parts in other words—with this engine. That makes them a lot easier to maintain. That’s exactly what boaters want.”

Since they were first introduced to the market in 2003, BRP’s Evinrude E-Tec direct-injection two-stroke engines have been catching a lot of interest. In 2004 they not only met the stringent new exhaust emissions standards set by the California Air Resources Board and the US Environmental Protection Agency, the direct-injection two-strokes garnered the company a clean air excellence award for clean air technology from the EPA, a first for marine engine manufacturing.

The EPA website report on the award states that “compared to a similar 2004 four-stroke engine, carbon monoxide emissions with Evinrude E-Tec are typically 30 to 50 per cent lower; and at idle are lower by a factor of 50 to 100 times.” In addition, Evinrude E-Tec emits 30 to 40 per cent less total particulate matter on a weight basis than a similar “ultra-low emissions four-stroke outboard," the report continues.

High praise indeed.

BRP is ramping up production and streamlining its outboard manufacturing division to focus on their Evinrude E-Tec two-strokes, offering a line-up that includes 40 to 250 hp outboard motors. Over the next few years BRP will roll out new models and “complete the family of products” by offering a range of products from 3 hp to 275 hp, says Pierre Pichette, vice president of communications and public affairs.

“Evidently there is a strong appetite for four-strokes, but we are making significant inroads to bring the E-Tec technology to the market,” Pierre says. “We’re a small fish in a big pond, but we’ve been hard-headed about moving forward and as a result our sales are growing.”

Mercury Marine is also investing in direct-injection two-stroke technology with major changes to their OptiMax line, and Yamaha continues to offer their two-stroke High Pressure Direct Injection (HPDI) series.

Despite the buzz BRP’s Evinrude line has created about new two-stroke technology, Dave Trott, sales manager with Seamasters Services Limited in Dartmouth, says from what he sees at the retail marine level, the market has made the shift toward four-stroke engines, and that’s where he thinks it will stay. “I think it’s safe to say the percentage of sales is definitely on the four-stroke side.”

Rick Layzell, national marine sales manager with Yamaha Motor Canada Ltd, and chair of the CMMA board of directors, estimates as much as 80 per cent of sales is already going to the four-stroke engines. It’s a trend that is only going to continue, he says.

“I think the market has already stated quite clearly that they want four-strokes. That’s where the market is and I think that’s where it is going to stay.”