For the 2009 model year Evinrude has announced the newest and smallest member of the E-TEC family of low emission outboard motors. It’s not only the smallest E-TEC but also the world’s smallest production direct-injection outboard engine, and there are a lot of big new features in this very small package.
For example, it’s a twin cylinder 576 cc engine, the biggest capacity in this HP size, but at just 66 kg (146 lbs) it’s also the lightest low emission engine of this size by a large margin. For this new E-TEC Evinrude’s designers had a long hard look at how outboards of this size have traditionally been made and they challenged many perceptions. Previously outboards of this size were often 3 cylinders for smoothness, or two cylinders for lighter weight, but with a roughness penalty. The E-TEC designers reckoned we could have the best of both worlds by using some of the 21st century’s computer design tools. Two cylinders keeps the weight and bulk down while easily providing all the power required, what was needed was a new approach to reducing engine vibration and how it is transmitted to the boat and crew. A sister company to Evinrude in BRP is Rotax, one of the world’s best known high performance engine builders and a world leader in pressed together compact crankshaft design. Rotax designed the new 25/30 E-TEC crankshaft using single piece conrods for the smallest mass, and a pressed together crank design to allow optimum counterweight shape and best balance.
E-TEC designers also redesigned the mounting system. Engines around 25/30 HP typically have 5 or 6 rubber mounts supporting the engine and transmitting the propeller thrust through the stern brackets to the boat. To reduce transmitted vibration those mounts are usually quite close together so that vibration forces have the minimum of leverage, but they are still some distance away from the engine’s pivot point, the steering axis. Vibration pulses from the engine try to rotate the engine around its steering axis, and the operator feels this as side to side tiller handle vibration. The new 25-30
E-TEC’s have a new approach – “focused” mounts. Computer modelling, shows how engine vibration forces act upon the steering pivot. CAD drawing of the new E-TEC mid-section shows how the new mounts are “focused” towards the steering pivot. This design also requires only 4 mounts to handle both steering and thrust forces. The large exhaust relief silencer attached to the rear of the exhaust housing ensures very quiet low speed operation.
The new E-TEC 25-30 mid-section also features a tuned exhaust system with separate inner and outer housings. A “wall of water” cooling system is used where cooling water on its way out of the engine is used to fill the space between the inner and outer exhaust housings to reduce noise and isolate the hot exhaust areas away from the outer housing. Previously these features were only found on much larger engines. All models also feature through tilt tube steering for remote steering applications and an easily user adjustable steering friction on tiller controlled models.
The heart of the new E-TEC is the two cylinder 576 cc (35.3 CI) powerhead. It is a loop-charged two cylinder 2-stroke with thin iron cylinder liners featuring a temperature and pressure controlled cooling system for best economy and lowest emissions. A plenum chamber style intake manifold with a single throttle valve improves mid-range power and further reduces engine noise while providing a very compact engine. Engine sensors for throttle opening, air temperature, engine temperature and crank position are also shared with the larger
E-TEC models for commonality of parts and reliability. The new 25/30 E-TEC powerhead also features multi-point oiling. An engine mounted 1.5 litre oil tank will supply enough oil for about one year’s boating for most recreational users. Inside the oil tank is an electronic injection pump controlled by the EMM.
Multi-point oiling means oil enters the engine at two points for each cylinder. Oil injected into the crankcase and lubricates the crank, rods, bearings and the cylinders at higher speeds, plus oil is also injected through the cylinder wall directly onto the piston skirts for optimum lubrication at slow speeds. The new 25/30 E-TEC, like all other E-TEC’s, features a fuel system with two fuel pumps, an inline fuel filter, a water cooled vapour separator and an electronically controlled E-TEC Direct Injection fuel injector for each cylinder. New ground was broken for the 25/30HP E-TEC by designing a fuel system that has no high pressure fuel lines to reduce the number of parts required and to take up less space. The vapour separator bolts directly onto the fuel injector housings. The vapour separator includes the high pressure fuel pump, a fuel pressure test point for simple diagnosis and a “roll over” valve that ensures the fuel system is sealed if the engine is removed from the boat and transported or stored horizontally, as engines of this size sometimes are. All Evinrude E-TEC outboards feature full electronic engine management and the new 25/30 breaks new ground here with the smallest most compact EMM (Engine management Module) so far. Simple diagnostics can, like all other E-TEC’s, be achieved by using the 4 red LEDs (light emitting diodes) on the EMM. The New 25/30 EMM mounts the LEDs internally, for minimum size, and uses a clear casing and potting compound so they can be easily seen. The four LEDs come on when cranking the engine to signify the main circuits are functioning OK, then when the engine is running the LEDs only come on to indicate a problem has occurred and in which area of the electrical system. 2009 model E-TEC’s feature a new fast rise time inductive ignition system called IDI ignition. Previously high performance 2-stroke engines used CD (Capacitor Discharge) ignition. CD ignition has a very fast rise time, so spark plug fouling is virtually eliminated. For low emission engines a multi-strike spark is used where, in some conditions, there can be up to 8 strikes for each combustion cycle. This to ensure that even at low speeds, when in stratified combustion mode, the fuel-air mix is always ignited on every stroke. However, CD systems have very brief spark duration so while the fuel is ignited every time, the gaps between multi-strike sparks sometimes means the fuel is not ignited at the ideal time for smoothest operation. The new IDI ignition system has one long spark discharge for each combustion event and always ignites the fuel at the optimum time. This results in smoother operation on all combinations of speed and load. Further, longer spark plug life is an added benefit as the single strike spark causes less spark plug electrode wear.
Evinrude E-TEC engineers are very aware that engines of 25/30 HP often go on heavy boats and it’s not unusual for the weight of the typical 25 and 30HP rig to double the when loaded. For example, a typical 4 to 5 meter aluminium boat with a 30 HP engine and one person aboard will weight around 350-400 kg. However, boats of this size can regularly hold up to 5 people and have a max load rating of 500 kg or more, so the rig when fully loaded it is more than twice the weight it was when lightly loaded. Engines for these rigs need to have a very broad torque curve to ensure good acceleration and load carrying ability. The power curve of the new 25/30 HP E-TEC models has been tailored for maximum mid-range torque, as the comparison of the new E-TEC 30HP with the older style 30 HP carburettor motor and a typical 30 HP
4-stroke demonstrates. Outboard engines of 25 and 30 HP are equally used in both tiller control or remote control modes and the new 25/30 HP E-TECs have completely redesigned the operator controls. The new tiller handle now has several new features mounted much more conveniently than previous engines in this size range. The new tiller handle has a divided attachment point at the engine for more strength and to provide a hand-grip to assist with carrying or installing the engine. It also now incorporates a top mounted shift lever for easy shifting without the need to reach back to the engine. At the twist-grip throttle end there is an adjustable throttle friction, plus the stop and start buttons. Power trim models will have the trim button at the end of the throttle twist-grip so the operator can use their thumb for trim operation, without the need to move their hand away from the throttle.The new tiller can also be fitted straight ahead or 20° to either side so the operator can sit to port or starboard, or almost directly ahead of the engine. This feature allows the operator to sit in the most comfortable location and to balance the boat. The tiller has a full down position adjustable stop so the tiller can be set from minus 6° to +20° for best comfort on boats with a big variety of transom angles, and it will also latch at tilt angles of 30° and 90°. A small release lever is located near the tiller pivot to unlatch the tiller when required.A new feature for the fisherman who likes to troll at slow speeds is an electronic low engine speed adjustment called Touch Troll. A switch on the tiller handle allows the operator to vary the idle speed by just “clicking” the switch while the engine is idling in gear. Each click moves the speed by approximately 50 rpm, over the range of 650 to 900 rpm. In addition, when operating at speeds up to 25% throttle, or about 2000 rpm, a touch on the Touch Troll switch will keep the engine at that RPM, without the operator needing to constantly hold the throttle. Clicking the Touch Troll switch will then also move the RPM up or down by 50 RPM steps for really precise setting of trolling speeds. To turn off this trolling speed control mode, the operator only needs to only rotate the throttle twist grip, either up or down.
For remote control models, the attachment points for shift and throttle control are included on all E-TEC 25 and 30HP models so that remote controls can be added at any time. Cable anchor points have been designed into the engine castings to reduce the number of parts required and for minimum weight.
The 25/30 HP E-TEC electrical system features modularised accessories. Not all models require battery charging or electric start, so these are not fitted to all models. When required they can be easily fitted as bolt-on accessories. As with all Evinrude E-TEC engines, the new 25/30HP models feature full compliance with all emission regulations including the US EPA, the European EU rules and the toughest of all the California CARB 3 star and the Australian VELS 3-star requirements. Australia and several other countries are also in the process of formulating outboard motor emissions regulations based on these stringent requirements.As with all E-TEC models, emission compliance labels will be prominently displayed on the motor covers. Note also the large bumpers on the aft face of the motor covers. These allow the engine to be laid down for transport or storage while protecting the motor cover finish. And best of all, the new 25/30 HP E-TEC’s will have all of the advantages that other E-TEC owners already appreciate.
To fit them into this relatively tiny package was an engineering challenge that has taken 4 years of design and development. BRP’s philosophy of light-weight, high-performance, quiet, low emission engines was developed through studies of what users really wanted in their recreational engines and then refined into the 4 main value propositions that underpin every E-TEC design.
EASY TO OWN AND OPERATE • 3 years/300 hours no dealer scheduled servicing • 3 year non-declining warranty • Lightweight Design • Easy to fit and transport • High output alternators CLEAN AND QUIET • CARB 3 Star, VELS 3 Star, EPA and EU emissions compliant • Extremely low carbon monoxide at idle • Low particulate matter emissions • No crankcase oil to dispose of • Quiet operation DQR (Dependability, Quality and Reliability) • Multi-point oiling • NASA developed Alloy Pistons • Large diameter bearings and shafts • Oversized robust gearcase • Full Electronic Engine Management POWER AND PERFORMANCE • More displacement for low stresses • Up to 30% more mid-range power • Superior hole shot and acceleration • Faster top speed • Excellent fuel economy