Evinrude E-TEC Overhaul

E–volutionary

Say goodbye to what you knew about 2-stroke engines with Evinrude’s E-TEC technology.

Sometimes what the eyes and ears register takes a while for the brain to assimilate, particularly when it’s seeing something rather odd — like the sight of a pair of running Evinrude E-TEC 250s on the back of a Triton 2895 center console. You know they’re running because you can see the healthy stream of water shooting out, but you know it’s a 2-stroke, so where is the accompanying noise, smell, smoke and vibration? Then your brain finally receives the real message: your preconceived notions about
2-strokes are due for a major overhaul.

The public perception of 2-strokes by many people is that it’s a dinosaur technology that is on its way to extinction by the powers that be who regulate environmental matters, especially in Cah-lee-for-nee-ya. Well, to paraphrase Mark Twain, “The reports of the 2-stroke’s demise are greatly exaggerated.” Evinrude’s new E-TEC line, which started production last year with models ranging from 40- to 90 hp, expands its lineup to include V6s from 200 hp to 250 hp. And this isn’t just a new and improved “fixed Ficht” engine, but a whole new way of taking 2-strokes well into the 21st-century.

The beefs against 2-strokes are largely directed toward the carbureted models, which for most of a century were practically the only outboard design available to consumers. They make a lot of power for their size, but get poor fuel economy because of one major design flaw: The exhaust port is still open while fuel is entering the combustion chamber. So like trying to fill a water glass with a hole in it, there was unburned fuel being released into the environment. The byproduct of that waste is smoke and noxious fumes. And then there was the excessive noise. When direct injection came along in the late 1990s, the problem of escaping unburned fuel was solved, but early models had some reliability issues. They were quieter and less smoky, but the 4-strokes held a significant advantage in these areas.

The next generation of 2-stroke E-TECs from Evinrude take these disadvantages and turn them into positives; one of the most significant improvements comes in the area of emissions. The bottom line is that all E-TECs are rated three stars, designating them as ultra-low emission engines by the California Air Resources Board (CARB), whose standards are even more stringent than those set by the 2006 EPA regulations. One of the ways Evinrude achieves these goals is by utilizing stratified combustion, which means at lower rpm only part of the combustion chamber receives a fuel charge. This lean burn process improves fuel economy as each droplet of gas is ignited by the double platinum tip spark plugs. The plugs emit a long spark at start-up and idle, and a short one at higher rpm when the cylinder is fully-charged with the optimum gas/air mixture that’s determined by its electronic brain, the EMM (Engine Management Module), which can make up to 8 million calculations per second. The E-TECs produce far fewer concentrations of deadly carbon monoxide than any other outboard, and although not yet regulated by American agencies, that’s likely to change in the future.

The biggest difference between the E-TEC and its Ficht predecessor is the way it delivers fuel into the combustion chamber. The Ficht models — which Evinrude still offers in mid-range power — use an electromagnetically controlled piston to hammer the charge into position to be burned and use a spring to return it to its starting position. It has only two basic positions: inject or retract. In contrast, the E-TEC injector uses a voice coil, just like the one found at the back of your stereo speaker at home to control the injector. This gives it not only the ability to allow the amount of fuel being delivered to be varied, depending on the situation, but when the polarity is reversed, the injector piston is actively pulled back. The result is a system that eliminates that clackety sound made by Ficht injectors at low rpm, and is approximately twice as fast, allowing it to operate at a higher fuel pressure.

Adequate lubrication is an issue for 2-strokes, and has traditionally been handled by mixing oil and gas prior to combustion, which is sort of a shotgun approach to lubrication. With E-TEC, the oil and fuel aren’t mixed before burning; instead, oil is squirted directly on those places that need it the most like connecting rods and bearings. As a result of Evinrude’s oil management scheme, the E-TEC uses 75 percent less oil than carbureted 2-strokes and half the oil of comparable direct-injected 2-strokes when using Evinrude’s XD 100T oil. In addition, the E-TEC has boron-nitrite honed cylinder walls that are porous enough to retain oil, like a seasoned skillet. This allows the E-TEC to be run wide open, right out of the box with no break-in period required. Amazingly, the E-TEC can even run when the oil tank is empty, due in part to its use of roller bearings. Its S.A.F.E. (Self Adjusting Failsafe Electronics) mode automatically drops engine rpm and allows you the ability to limp home for up to five hours in the event of certain engine malfunctions.

The V6 E-TECS use the proven 3.3L block, which Evinrude and its sister company, Johnson, have used for years, but there have been many improvements, like the new cooling system. One of the most interesting improvements came when an Evinrude engineer was surfing the web in 2002 and came across a new aluminum alloy that was developed by NASA. It was 2.5 times stronger at operating temperature, and more resistant to wear. Within a year, Bombardier Recreational Products (BRP) was licensed to begin production of its new “super piston.” Even better, this wasn’t some exotic metal with price tag to match, but rather a raw material that could be manufactured for around a dollar a pound.

So, how does the E-TEC perform? Idling out on a Triton 2895 center console, a beefy 29-footer with a pair of 250s on the transom, the noise level is a mere 62 decibels, thanks in part to the E-TECs ultra-slow 500 rpm idle speed, which will be good news for those who like to troll slow. To further quiet the engine, molded foam cowling inner liner is used along with an idle air bypass and a newly designed piston assembly that reduces the sound of piston slap. A clever innovation called a Helmholtz resonator waits for a certain sound to occur, then produces a sound of the same wavelength and amplitude, but in the opposite phase, which in effect, cancels it out.

Jamming the throttles results in an immediate surge of acceleration that puts the Triton (more like a quad-ton the way it’s loaded) on plane in around four seconds. The power curve remains very flat all the way to a top speed of almost 58 mph. Mid-range acceleration is very crisp and will be very useful in heavy sea conditions where sudden bursts of power are sometimes needed. Fuel flow at 4,000 rpm for each engine is reported to be less than 12 gallons per hour by Evinrude sources.

The engineers at BRP set out to make the Evinrude E-TEC as user-friendly as possible, and ended up with a design that needs no scheduled dealer maintenance for up to three years of normal recreational use or 300 hours, and because it’s 2-stroke, there are no oil changes. Winterization happens automatically with just a few keystrokes, and come spring, no tune-up is necessary. Because the fuel system is closed, you don’t have to worry about oxidation, and even after months of not running, it will start on the first revolution. It has a magneto, so you can even pull start it if you have a battery problem.

The family of V6 E-TECs come in shaft lengths of 20-inch, 25-inch, and 30-inch and weigh between 516 and 538 pounds, making them the lightest direct-injected 2-strokes on the market. They’re actually 125 pounds lighter than the Verado 4-stroke (25-inch shaft), making them a good choice for those who demand a great hole shot. There is a special Saltwater Edition series that is especially designed to resist the ravages of a harsh marine environment.

So, what do you call a 250-hp engine that is the lightest in its class, requires no scheduled dealer maintenance for three years, meets all environmental requirements, gets outstanding fuel economy, is quiet, and even looks great? The answer.

Performance:
E-TEC 250
(25-inch shaft)

Performance data was gathered with twin 250-hp E-TECs on a Triton 2895 with three people on board and 170 gallons of fuel.

Top Speed 57.8 mph
Time to Plane 4.2 seconds
Decibels @ idle 62 dB-A
Decibels @ 30 mph 83 dB-A
Decibels @ WOT 93 dB-A

By Alan Jones

March 2005