by John Page Williams

Back in the mid-1990s, when the Environmental Protection Agency released its timetable for the mandatory reduction of outboard engine emissions under the Clean Air Act, the year 2006 seemed far, far away. Pardon the cliche, but... where did that time go? Here we are almost halfway through 2004 and we still haven't gotten around to organizing and labeling all those cans of paint in the boat shed.

The six major outboard engine makers in the U.S. market, you'll be happy to hear, have not frittered away the decade. They have in fact, with only a few exceptions, already met the 2006 deadline. Three brands--Evinrude (a division of Bombardier Recreational Products), Honda and Suzuki--sell only 2006-standard engines. And the others--Johnson (also Bombardier), Mercury, Tohatsu/Nissan, and Yamaha--are most of the way to that goal. All of the new models we look at here easily meet the 2006 standard; indeed, all but two of them meet the even stricter California Air Resources Board (CARB) "three-star" ultralow emissions standard, which will be required in that state by 2008.

The happy upshot for us boaters, of course, is that we get a whole new breed of four-stroke and direct-injection two-stroke outboards--engines that are not just cleaner, but also much quieter and, in this year of spiraling gas prices, much more fuel-efficient than their two-stroke predecessors.

Here are some notes on new outboards introduced for the 2004 model year, many drawn from my first-hand operating impressions. While the largest engines tend to draw the most publicity, you'll note that the manufacturers are sensitive to a broad range of boater needs; the wizardry in this year's class ranges from 8 to 300 hp.


Up to 30 hp
Much of the interest in this power class today comes from people with inflatables. Deploying a dinghy from a cruising boat usually means removing the outboard from an onboard rack and lowering it to the inflatable, then reversing the procedure on return. Light weight is a huge benefit here. Honda started a trend last year by offering new 8-hp and 9.9-hp four-strokes that weigh only 92 pounds, with short (15-inch) shafts and manual starting. This year, Mercury has brought out similar engines that weigh just 84 pounds, and Tohatsu/Nissan has gone down even further--to 81.5 pounds. Engines with long (20-inch) and extra-long (25-inch) shafts and electric starting weigh 5 to 20 pounds more.

All of these engines are smooth, quiet and powerful for their size. They burn fuel so slowly, in fact, that it's important to use fuel conditioner not just for winterizing, but throughout the season (at half dose) to keep gas from going stale and gumming up the carburetor. The engines are appropriate not only for four-person inflatables but also for small aluminum skiffs and johnboats, as slow-trolling "kickers" for 18- to 22-foot fishing boats with large main engines, and as auxiliaries for small cruising sailboats.

For small fishing boats and inflatables, Mercury and Honda offer long tiller handles with both throttle and gearshift. For kicker and auxiliary applications, where shove is more important than speed, they offer extra-low 2.42:1 and 2.33:1 gear ratios and four-blade propellers. Electric starting is available from all three manufacturers, as are 6-amp alternators (12-amp on Honda electric start models) for powering lights, VHF radios, depthsounders and GPS plotters.


40 to 115 hp
The most striking new engines in this range are Evinrude's E-Tecs. These are direct-injected 2- and 3-cylinder outboards of 40 to 90 hp that use a completely new electronic system to inject precisely calibrated and timed plumes of atomized gasoline into the cylinders for clean, efficient burning. The electromagnetic technology that drives the fuel injectors is adapted from acoustics engineering; it allows the system to function at engine speeds above 6000 rpm with the fidelity of a fine stereo speaker.

In size and overall build, the E-Tec engines hark back to the 40- to 75-hp two-strokes that Evinrude and Johnson made in the 1970s, '80s, and '90s--compact power heads on oversize lower units, with heavy-duty gear cases that can swing relatively large 13- and 14-inch propellers for good combinations of speed and thrust. The new engines, though, weigh only a little more than those two-stroke ancestors, while running much quieter and cleaner on less fuel. I've run E-Tecs, both a 40 and a 90, on rigid-bottom inflatables. They are as quiet as comparable four-strokes, but as quick in acceleration as conventional two-strokes. I wasn't able to put a fuel-flow meter on either of them, but I have seen trustworthy independent test results that show excellent fuel economy. At 320 pounds, the 90 is one of the lightest new-generation engines in its power class. It should balance well on 16- to 18-foot skiffs like the 16-foot-7-inch Boston Whaler Montauk, the Aquasport 17 and the Maritime Skiff 18. Bombardier is offering a three-year "non-declining" warranty with an optional four-year extension on E-Tecs. The company has designed the engines to run 300 hours or three seasons before the first service is needed. Winterizing is done by the owner, following a simple set of instructions that cause the engine to fog itself with oil and shut down. The engines can also be dealer-programmed to run on a special Evinrude synthetic oil that lasts 50 hours per tank.

Although Mercury offers strong, quiet 75-, 90-, and 115-hp four-strokes, the company has this year brought out lighter, quicker three-cylinder OptiMax direct-injected two-strokes of the same power ratings. These engines weigh 55 to 70 pounds more than the 70- to 90-hp  E-Tecs, partly because they have larger piston displacement (1.5 liters versus 1.3 liters), which means more power for skiing and carrying heavy loads. The greater weight, on the other hand, demands attention to hull balance.

Though these engines are new, Mercury has been building larger OptiMax engines since the mid-1990s, and the company seems to have worked all of the bugs out of the basic system--which relies on an air compressor to pressurize fuel but runs at lower pressure than the E-Tec and Yamaha High Pressure Direct Injection (HPDI) systems. Mercury has also found ways how to make Optis quieter, and those lessons have transferred to these three-cylinder models.

Three years ago, Tohatsu (which also markets its engines under the Nissan brand) developed direct-injected two-cylinder, two-stroke, 40- to 50-hp engines with an air-assisted system similar to Mercury's, calling it Tohatsu Low-Pressure Direct Injection (TLDI). Those engines have proved to be efficient and durable, with operating systems that are significantly simpler than those of the other direct-injected engines, and they qualify for a two-star (very low emissions) CARB rating.

This year Tohatsu has introduced three-cylinder 70- and 90-hp TLDI engines, which share a basic power head. At 315 pounds, they are the lightest in the class and should prove useful on the same kinds of 16- to 18-foot boats. A friend of mind in Norfolk is running a pair of 90s on his 21-foot catamaran. He is pleased with their "sewing machine" sound, light weight for good balance on the cat, and strong power. I've had a flow meter on them and can attest to their fuel efficiency.


135 to 150 hp
Honda's BF 130-hp engine, introduced in 1998, quickly gained a reputation for strong performance and bulletproof durability (it is, after all, based in part on the original four-cylinder Accord engine), but at 496 pounds, it's the Baby Huey of its power class. For 2004, Honda has introduced completely new BFs that are not only stronger (135 hp and 150 hp) but also about 20 pounds lighter than the 130.

The heart of these new four-cylinder engines (which share parts with the newest four-cylinder Accord and the CRV) is a huge microprocessor that controls, among other things, a "lean burn" combustion system that works in tandem with a three-way cooling system to reduce fuel consumption while preventing overheating at all speeds. The processor also allows the use of a multifunction digital diagnostic gauge that measures not only engine rpms but also operating hours, temperature and fuel flow. I've tested a pair of the 150s on a 25-foot catamaran and a single on a 22-foot fishing skiff. They are even quieter and more fuel-efficient than the BF130, and given Honda's track record for quality, it's reasonable to expect them to last at least as long.

The first 150-hp four-stroke outboard to come onto the market, however, was Yamaha's four-cylinder F150, introduced at the end of last summer. This is a versatile engine, effective on everything from a 26-foot walkaround family boat to a 21-foot center-console utility. At 466 pounds, it's also lighter than the new Honda, even though it has more piston displacement (2.7 liters versus 2.4). The F150's narrow profile makes it good for twin-engine applications. Indeed, the first ones I ran were on a 25-foot cuddy-cabin hull. Performance with the pair was excellent, and in fact just one of them was strong enough to get the boat on plane and up to about 25 knots. That kind of power redundancy could prove very useful on long runs. Meanwhile, fuel economy (measured with an optional digital multi-function gauge) was excellent, and operation was as quiet as we have come to expect from Yamaha four-strokes.


The Big Boys
The big news at this year's Miami Boat Show was the introduction of Mercury's long-awaited "Project X" supercharged four-stroke, in-line six-cylinder outboards. Six years in development and named Verado, they come in 200-, 225-, 250- and 275-hp versions. Mercury engineers pretty much started from scratch in developing a four-stroke that was not only quiet and fuel-efficient but also had the quick acceleration of a conventional two-stroke. In a field dominated by V-6 engines, the in-line-six design is unusual.

This is the first supercharged outboard engine on the market, and that certainly helps the Verado pump a lot of power out of a relatively small engine block. With a displacement of only 2.6 liters, it's actually smaller than the Yamaha F150--and much smaller than the comparably powered four-strokes (all in the neighborhood of 3.5 liters). To regulate the internal pressures of supercharging, Mercury has developed the SmartCraft Engine Guardian protection system, which constantly measures engine conditions in order to control the supercharger's boost pressure and prevent damage. The SmartCraft system also integrates engine operations with electrohydraulic power steering and Mercury's DTS digital throttle/shift controls with digital gauge system.

At 649 pounds (25-inch shaft), the Verados are heavier than their Honda, Suzuki and Yamaha V-6 competitors (599, 580 and 583 pounds, respectively), but because of their narrower in-line configuration, twin Verados can be mounted closer together. This winter I had a chance to run a pair of Verado 250s on a beefed-up 25-foot center-console built for offshore fishing. As you might guess, the boat was a rocket (50 knots at full throttle), but the engines were quiet, very fuel-efficient, and--according to my stopwatch--extraordinarily quick. If the Engine Guardian system is effective, the Verados will set a serious performance standard.

Meanwhile, Suzuki last summer brought its DF 200- 225- and 250-hp V-6 engines to market. True to the tradition established by the company's award-winning DF 40- to 140-hp four-strokes, the big V-6s are not only quiet and efficient but exceptionally strong. Suzuki builds its mid-range and large engines with low gear ratios, which allow them to use large propellers--for lots of thrust at all speeds. The new DF V-6 engines are the only ones in their class that can turn 16-inch props; the competitors max out at 15.5 inches. The difference may not sound like much, but on some large, heavy hulls, such as catamarans over 30 feet, the Suzukis are overachievers because of it.

My only experience with a Suzuki V-6 so far is a test of a 23-foot center-console with a DF225, and that combination performed beautifully at all speeds. Suzuki's engines have a solid reputation for durability, and they are arguably the quietest of the breed. (By the way, Bombardier and Suzuki have an arrangement under which Suzuki builds all of the Johnson four-stroke outboards, including the 200- to 250-hp engines, which are essentially the same as the DFs described here.)

The largest stock outboard on the market, however, is Yamaha's new 300 HPDI, a "thundering" 3.3-liter, 300-hp V-6 that offshore anglers are mounting as twins and even triples on 32- to 38-foot fishing rigs. The 300 is actually a souped-up version of the 250 HPDI released last year, with higher fuel pressure and modified fuel mapping in the microprocessor. I had the opportunity to run a 250 on a 23-foot center-console fishing boat last summer and have spent time on smaller 150 HPDIs on some friends' boats. These CARB two-star-rated engines differ from the other brands' direct-injected two-strokes in that they shut down several of their cylinders at idle and low speeds, bringing them back as speeds climb over 2000 rpm. Fuel efficiency at these low speeds is not as good as that of the competition, but between 3500 and 4500 rpm, HPDIs tend to be best in class. Cruisers and anglers who want quiet, smooth, efficient low-speed operation for sightseeing and trolling will favor Yamaha's F-series four-strokes, while those seeking fast cruising speeds may be more pleased with the HPDIs.


Some Conclusions
This last distinction raises an important point. While running outboards has become much more pleasant, choosing the right one for your boat has become more complex. These engines are all heavier than their predecessors, though within any power range, there are variations. The four-strokes are generally not as quick as the old two-strokes, but they sometimes outperform them in terms of pushing power. A boat that runs well with a 90-hp two-stroke may become badly stern-heavy with a 90-hp four-stroke, but it may work beautifully with a lighter 60- to 70-hp four-stroke. The technology difference illustrated by the Yamaha HPDIs and F-series four-strokes can be important. The direct-injected two-strokes are lighter and nearly as fuel-efficient as the four-strokes, but they tend to be louder and in some cases rougher-running at low speeds (though still far better than the old two-strokes).

In the end, it's more important than ever to pay attention to factors like hull balance and how the boat will be used, when selecting a new-generation outboard. Beyond that, though, it's clearly a win-win situation. We get engines that are quieter, more durable and more fuel-efficient, while Mother Earth and our lungs get cleaner air.