Evinrude E-TEC 175

Lean machine

The E-TEC 175, the midrange engine between the 150 and 200, is not only lighter its competitors, but also scores well on both bottom end and Wide Open Throttle fuel efficiency. It’s well suited to aluminium and fibreglass hulls in the 5.5 to six-metre range and provides acceleration matched only by its Mercury OptiMax and Yamaha HPDI 175 competition. But, unlike the competition, it complies with CARB 2008 and Australian OEDA “3 Star” exhaust emission requirements.

While evaluating E-TECs at the Ralph Evinrude Test Center in Florida during March, I spent some time testing a 175 on a fibreglass 5.7m 190 Sea Chaser Centre Console built by Carolina Skiff. Nicely built with typical US features, such as unboltable mouldings for the cockpit sidepockets, the 190 has a 16-degree transom deadrise, moderate compared to our homegrown boats but still deep enough to ride well over a short steep chop without compromising hull stability.

Spinning a 17-inch pitch Viper prop and pushing a total of 1450kg, including three adults, the 175 is well matched to this hull. According to the Lowrance GPS and Bombardier “I-Command” fuelflow system fitted, it trolled us at only 3.2kmh and 500rpm using 0.7lt/h (the same as a four-stroke Suzuki DF40) and 36 per cent less than what an OptiMax 175 uses. Increasing the revs to 1000 returned 6.3kmh and 1.7lt/h, while at 2000rpm the averages were 11.6kmh and 8.5lt/h. A clean plane was achieved at 30.6kmh and 2800rpm, and cruising quietly at 4000rpm the averages were 52.0kmh and 25.0lt/h.

At a fast cruise of 5000rpm the averages were 68.1kmh and 47.3lt/h, but extracting the last 800rpm out to 5800rpm and WOT averaging 78.1kmh increased the fuelflow to 59.8lt/h.

Like all E-TECs I’ve tested, the demo 175 started instantly hot or cold with no oil smoke appearing at any time although there was a slight oil smell when backing upwind. Due to the injector design where the fuel plunger returns magnetically and not by a spring, there is none of the injector “click” that occurs with OptiMax and Yamaha HPDI engines, making the E-TEC 175 a very quiet engine when trolling. And due to effective soundproofing the E-TEC 175 is also much quieter than its direct competition at or near WOT.

Maintenance is straightforward with the lower cowl separating for complete powerhead access. For saltwater usage, the throttle and gearshift linkages should be lubricated once a year and the prop removed every six months to check for stray fishing line on the propshaft. Otherwise no scheduled maintenance is required for the first 300 hours or three years.

In previous E-TEC engine reviews, I’ve discussed the fuel injection pressure and air/fuel ratios. However, when I met with Bombardier engineers in Waukegan, Illinois, before flying to Florida, I discovered the injection pressure is set at 43 bar or 600 psi. Also, the air/fuel ratio on stratified mode (up to 1800rpm) is 14.7:1 at the spark plug but the overall ratio in the combustion chamber is as lean as 70:1. The term “stratified” is misleading as the injector spray has a sufficiently narrow angle to be directed at a recess in the piston crown for complete combustion when ignited, even though the fuel droplet size is around 32 microns compared to five or six for OptiMax engines. When operating on homogenous mode the ratio is 14.7:1, not 25:1 as reported previously.

In coming issues I’ll discuss how the variable voltage alternator functions, more on the fuel injectors and why E-TECs don’t require a running-in period.