By Mike Milne

The past two decades have brought a wave of environmentally friendly engine technology onto the waterfront, and the test team at Boats&Places and PowerBoat Television has been there to evaluate and experience it.

We’re pretty sure clean technology would have arrived eventually, but state and federal regulations in the U.S. – now largely mirrored by Canadian regulations – certainly gave it a push.

Every once in a while, there is an “Aha!” moment when you recognize how far marine engines have come.

Boaters can credit the California Air Resources Board (CARB) and the U.S. Environmental Protection Agency (EPA) for starting the emissions regulation and control ball rolling. CARB dates back to the early 1960s and the EPA showed up in 1970 to put some teeth into the U.S. Clean Air Act.

California’s climate and clogged freeways meant something had to be done. CARB cleaned up automotive emissions in California and EPA took over from there.

As boaters know, where automobiles lead boats are sure to follow. As on the automotive scene, there have been many experiments with electric motors and alternative fuels, but the biggest emission-driven changes and developments in recreational boating have come in the area of gasoline-powered engines, what the EPA calls “marine spark-ignition engines and vessels.”

When emission regulators initially caught up with marine engines in the 1990s, two-stroke outboards – then the mainstays of the marine power market – were in the crosshairs.

Like the Evinrude 9.9-hp outboard that powered my childhood cottage utility boat, two-strokes were pretty much bulletproof, thanks to simple technology and a steady diet of lubricating oil in their fuel. You got used to the heavy odor of burnt oil and the rainbow oil slick in your wake. Today’s outboards smell a lot better, but are also quieter and much more fuel-efficient. Those old two-stroke outboards, considered “classics” today, are primitive by comparison

The EPA’s call for about a 75 percent reduction in exhaust emissions between the late ‘90s and 2006 was a big part of the impetus for a wave of research and development.

These days, spark-ignition engines and vessels, including personal watercraft, are largely four-strokes. The only two-strokes on the marine marketplace in Canada (a minority) are outboards with high-tech direct fuel injection. They are just as clean or cleaner than the four-stroke outboards and produce even less carbon monoxide.

On the diesel side, engine builders have also been forced to redesign their powerplants. The Marine EPA Tier 3 that came into effect about two years ago called for a 40 percent reduction in particulate matter and 20 percent cuts in nitrogen oxides (NOx) and hydrocarbon (HC) emissions.

As the EPA pointed out in a 2008 paper on “spark-ignition” or non-diesel emissions, the move to four-stroke outboards with electronic fuel-injection (EFI) and precise electronic control was effective in reducing emissions. PWCs have also moved to four-strokes. Improved fuel efficiency was more than a side benefit. For inboards and sterndrives – still built using largely automotive-sourced four-stroke blocks – EFI, exhaust-gas recirculation and more precise controls help, but catalyst-equipped exhaust systems are also needed.

Diesels use a variety of methods, but as with spark-ignition inboards and sterndrives, advanced electronic control systems are most helpful in providing effective solutions.

The most recent emission-oriented regulations to come into effect eliminate what are called “evaporative emissions” and have forced boatbuilders to install more costly fuel lines and tanks. The changes are neither sensed nor experienced. That’s not the case with the evolutionary changes in engine technology over the past two-and-a-half decades.

PowerBoat Television host Mike Gridley first realized what four-stroke technology meant in the early 1990s. As a cruiser, day-trips with friends in two-stroke-powered inflatable dinghies were part of the lifestyle, but, says Gridley, “my big moment was the first time someone pulled up beside all of us – with our smoking two-stroke-powered inflatables – with a 9.9-hp Honda outboard on the back of his dinghy. It was clean and purring away like a kitten, while the rest of us were choking back oil fumes.”

As outboard manufacturers embraced and developed new four-strokes, there have been even more advances in convenience, aesthetics and fuel efficiency.

When I tested a new fuel-injected 40-hp Yamaha four-stroke seven years ago, for example, quiet four-stroke operation was something I had begun to take for granted, but the fuel economy in the new F40 meant you could literally run the engine all day on a tank of gasoline. Compared to old-school two-strokes the difference was like night and day.

Revolutionary change – for example, an electric-powered planing boat priced like a gasoline-powered competitor and capable of equal range and performance – is still in the future. As electric automotive manufacturers (led by the likes of Tesla Motors) develop ever-better, every-cheaper batteries, that future is rapidly approaching.

Propane-powered outboards are already here and provide comparable performance and lower emissions than their gasoline-powered competitors. Lehr launched a new 25-hp LP25 engine for 2016 and also has 2.5-, 5-, 9.9- and 15-hp outboards in its lineup. Bigger outboards aren’t likely feasible without more propane filling stations on the waterfront.

Propane, easily transportable as a liquid when compressed, is a by-product of natural gas and petroleum refining and usually less expensive than gasoline. Because it has three carbon molecules as opposed to eight in gasoline, it naturally has lower carbon emissions.

A test-drive I did with a Lehr outboard over a year ago confirmed my hunch that propane could be fuel of the future that is here today. Installed on a 11’6” Zodiac inflatable, the Lehr L15 started easily, had a strong and immediate throttle response and pushed the Zodiac to a top speed of 24 mph. It was also quiet and odour-free.

Honda brought the first of its four-strokes to Canada in the early 1970s and slowly made inroads, giving a few boaters a taste of the environmental advantages and fuel-efficiency of four-strokes.

By the early ‘80s market leaders Mercury Marine and OMC were still selling two-stroke outboards ranging up to 300 hp. Yamaha and Suzuki initially came onto the Canadian market with two-strokes but soon moved to four-strokes.

There was experimentation along the way, with the much cleaner direct fuel injection two-stroke technology. OMC (then building Johnson and Evinrude outboards) favoured the European FICHT direct injection technology and Mercury chose to integrate Orbital technology from Australia. Sea-Doo also built a few Orbital-based direct-injection two-stroke models before switching to four-strokes. Merc still builds a successful and popular range of six direct-injection OptiMax outboards from 115 to 250 hp, based on licensed Orbital technology.

Mike Gridley credits the continuing popularity of OptiMax outboards, like the 250 Pro XS he tested on a Nitro bass boat recently, to “two-stroke torque-punch sensation . . . that you just don’t get with a four-stroke.” Four-stroke manufacturers have concentrated on building up mid-range power and “flattening out the torque curve” of their new engines, but direct-injection two-stroke torque is hard to beat.

OMC went bankrupt largely due to the failure of FICHT technology, but the engine business was purchased by BRP. Evinrude outboards are now built using newly developed E-TEC direct injection two-stroke technology.

Tohatsu also builds seven models of direct-injected two-stroke outboards from 25 to 115 hp, including two with water-jet drives. The engines are equipped with TLDI (two-stroke low pressure direct injection) systems. Like OptiMax they use technology licensed from Orbital. They are sold alongside Tohatsu’s lineup of 2.5-hp to 50-hp four-strokes.         

While Mercury and Tohatsu continue to build clean two-strokes alongside four-strokes, Yamaha and Suzuki made early commitments to four-strokes in order to meet EPA-required emission reductions. Despite keeping a toehold in the DI two-stroke market, Mercury also made a broad-stroke commitment to four-stroke clear fairly early – developing the Verado lineup of supercharged four-strokes from scratch and launching 150- to 300-hp versions in 2004. It now sells a lineup of four-strokes from 2.5 to 400 hp (taking into account the Mercury Racing outboards).

Outboard manufacturers may have been pushed by regulations to develop cleaner, more fuel-efficient outboards, but that has also given them an advantage, especially in mid-range power applications.

Steve Bull, co-host of PowerBoat Television, once a devotee of cottage-country sterndrives, says “my mindset has shifted with regard to outboards in the past two years.

“Outboards like the Mercury Verado are quiet and wicked-powerful; 300 hp is no big deal any more, 350 hp is all but standard for 2016 and Mercury’s 400-hp introduction last year upped the ante even more.” As well as being light and powerful, says Bull, outboards also free up onboard space for relaxation or storage.

Electric power promises the ultimate in emission-free boating. Until recently, though, widespread applications in North America have been limited to auxiliary trolling motors on fishing boats. Electric outboard builder Torqeedo, launched in 2004 in Europe, has already built a strong following with a lineup of engines ranging right up to the Deep Blue, capable of producing the equivalent of 80 hp.

Unfortunately, the cost of four batteries raises the price of the engine to over $120,000. For boaters on electric-only lakes, it may worthwhile. But for wider applications, battery prices will have to come way down.

Even powered by more traditional fuels, new-technology is never cheap, but the boating experience it delivers always puts more pleasure in our pleasure-boating. Clean air, increased fuel-efficiency and reliability are all very beneficial side effects of emission regulation.