While emissions don’t impact the speed of the boat, hydrocarbons and nitric oxides contained within them can cause some other things to happen, like acid rain. It can kill trees, and in lakes and rivers it can change the pH level of the water to the point where marine life starts to die.
EPA emissions standards for outboard engines began to be phased in during the late 1990s and two-stroke engine makers responded with direct fuel injection outboards that eliminated the carburetor and provided better fuel economy in addition to lowering emissions. California, which has the worst smog pollution in the United States, enacted even stricter emissions regulations (CARB) for outboards sold in that state, and they went into effect sooner than the EPA 2006 guidelines.
The California Air Resources Board (CARB) instituted a star numbering system to identify the cleanliness of an outboard motor. A three-star certified motor today emits less than 10% of the emissions recorded from an average pre-1998 outboard. Virtually all outboards sold in the U.S. today have a three-star CARB rating. But among all of them, the 2-stroke Evinrude E-TEC G2 has the lowest emissions of all.
When the total carbon nitric oxide and carbon monoxide levels are measured using EPA standards in compliance tests of these five engines, the Evinrude E-TEC G2 engine scored 77.8, the lowest of any major 150-horsepower 4-stroke engine on the market. The next closest competitive outboard brand scored 89.4. And the worst was the Yamaha 150-horsepower 4-stroke scoring 154.6, or nearly twice the emissions of the Evinrude E-TEC G2 2-stroke 150.
The entire Evinrude E-TEC outboard lineup is 100% globally compliant with all environmental regulations on the world’s waterways, including Lake Tahoe in California, and Lake Constance in Europe, which have the toughest emissions requirements in the world. Evinrude E-TEC was also the first outboard to ever be awarded a Clean Air Excellence award, that recognizes and honors outstanding innovation efforts to help make progress in achieving cleaner air.
Cleaner burning also means more efficient burning. Evinrude’s E-TEC G2 has direct fuel injection into the cylinder. The 4-stroke outboards have indirect fuel injection, which is outside of the combustion chamber.
It also has an electromagnetic fuel injector. Like the driver on a stereo speaker it pulsates thousands of times a second, and varies depending on how much fuel is needed.
A dome in the top of the combustion chamber permits stratified combustion at low RPMs. In this case, only a miniscule amount of fuel… as little as the size of a few champagne bubbles, combust in the dome and don’t need the whole cylinder, or a lot of fuel, to do their work.
No other outboard in class has these three elements. And they are largely why the Evinrude E-TEC G2 engines have more complete burning resulting in the lowest emissions and excellent fuel efficiency.
It’s clear to see why emissions are so important to the Evinrude E-TEC G2 lineup and how it helps the outboards be so fuel efficient. And this is just one of the many attributes that makes these engines so popular and reliable.