• The Genesis of the Evinrude E-TEC Outboard

    Dividing Lines

    Four-stroke engines have benefitted from decades of refinements in the automotive industry, and designing an emissions-friendly four-stroke outboard would be a relatively straightforward process. Much of the technologies developed for the cars we use today could be incorporated into outboard engines to some degree, but there are definite downsides. When compared to a two-stroke engine, generally, a four-stroke engine of equivalent horsepower will have twice the components and many more moving parts. Things such as camshafts, timing chains, and gears, and an oil sump simply do not exist in a two-stroke engine. This also means that a power-equivalent four-stroke engine will almost always weigh more and be larger in size -- a very negative trait in an outboard-powered boat. Furthermore, the added mechanical components in every four-stroke engine increase operating friction, adding to parasitic power losses which must be overcome. But the most important difference is in how these two engine designs principally function; the two-stroke engine produces power on every cycle of the piston, which is every revolution of the flywheel. The four-stroke engine must use a separate, non-power cycle for expelling burned gases out of the combustion chamber. Because of that required exhaust gas purging cycle, a four-stroke can only produce power on every other revolution of the flywheel.

    There were indeed challenges to overcome with the four-stroke engine platform for an outboard engine application. Even so, this became the platform of choice for most of the industry. It was viewed as being the easiest to develop for future emissions requirements, and it was a common belief at the time that the two-stroke engine would be incapable of matching the emissions performance of four-stroke designs. It was also a misconception that emissions laws actually outlawed the two-stroke engine altogether. This of course, was false - the EPA regulations stipulate maximum allowable limits for hydrocarbons (unburned fuel) and nitrogen oxide (NOx) as well as carbon monoxide (CO). The total hydrocarbon emissions reported by any particular engine or type of technology did not matter to the EPA; just the maximum emission limits that they regulated. Put simply, the EPA regulates emission levels, not engine technology.

    And while it seemed that the industry would, as a whole, move toward four-stroke outboards, there was an exception. It might be difficult to believe, but the technology that was to be the genesis of what would be the emissions-compliant two-stroke outboard engine was developed over 90 years ago, in 1925. This is direct fuel injection or as it is known commonly in today’s times as DFI. Its history might suggest that direct injection is not much different than the fuel injection systems that became common in the 1980s. However, the opposite is true; direct fuel injection offers important advantages over intake manifold injection systems, and those advantages would open the way for the new generation of emissions-compliant, high-performance two-stroke engines.

    2006: Engine testing in Key Largo, Florida. The famous Evinrude E-TEC test boat rigged with a Yamaha four-stroke for performance comparison testing. This boat is always a favorite.
    Traditional fuel injection methods as we have commonly known, injects fuel into the engine’s intake manifold, where it then mixes with air along its way, passing through the intake valve(s) and on into the combustion chamber. This technology is certainly a step above carburetion, and was not so difficult to implement into automobiles, and ultimately, outboard engines. It offered increased power by means of more precise fuel metering and delivery.

    By contrast, direct fuel injection delivers gasoline at very high pressures directly into the combustion chamber after the exhaust port is closed by the piston, which offers an extremely precise delivery of fuel, resulting in more power and fuel economy. By injecting the fuel directly into the combustion chamber, the inefficiencies of passing a charge through the intake manifold and valves are bypassed. That means combustion will be much more complete, and thus, leaving less byproducts of combustion – a much ‘cleaner’ engine than the traditional two-stroke of previous years. The downside to direct fuel injection is that it is a more complex system than ordinary automotive-style fuel injection. Thus, a system had to be developed for use in two-stroke outboard engines that was accurate enough to minimize emissions yet not be super expensive or unwieldy.
    Comments 19 Comments
    1. baja200merk's Avatar
      baja200merk -
      Nice job good read
    1. CRH1's Avatar
      CRH1 -


      Looking forward to part 2
    1. Instigator's Avatar
      Instigator -
      Nicely done Greg.

      The G-2 is the mack daddy and cant wait ti read about it.
      It is the "starboard starboard motor" and is amazing that anyone would make the investment to make that motor.

      Thank you.

      Gary
    1. DanUmbarger's Avatar
      DanUmbarger -
      Great read Greg, can't wait for part2...Thanks
    1. mjw930's Avatar
      mjw930 -
      Greg,

      Would it be safe to say the only thing that holds the G2 or the E-TEC in general back is the lack of a lower unit suitable for surfacing applications, costs aside?
    1. David Borg's Avatar
      David Borg -
      Thank you Greg. Great read
    1. Scream And Fly's Avatar
      Scream And Fly -
      Quote Originally Posted by mjw930 View Post
      Greg,

      Would it be safe to say the only thing that holds the G2 or the E-TEC in general back is the lack of a lower unit suitable for surfacing applications, costs aside?
      I think that could be accurate, however, as I researched the G2 I learned that the current Lightning II lower unit is tested at over 90 MPH, and can run surfaced. Not like a Sportmaster of course, however unofficially, it has run over 100 MPH without modification. Never know what the future brings, though!
    1. Scream And Fly's Avatar
      Scream And Fly -
      Quote Originally Posted by David Borg View Post
      Thank you Greg. Great read
      Thank you David, I really appreciate you taking the time to read it

      Greg
    1. Scream And Fly's Avatar
      Scream And Fly -
      Quote Originally Posted by Instigator View Post
      Nicely done Greg.

      The G-2 is the mack daddy and cant wait ti read about it.
      It is the "starboard starboard motor" and is amazing that anyone would make the investment to make that motor.

      Thank you.

      Gary
      Thank you so much Gary. I knew you would be interested in this article. The G2 is really a different outboard in most respects, which is one reason I decided to make the G2 an entirely separate part to this. Originally, the G2 was going to be incorporated into this article, but it really deserves its own feature article. I had great fun with the G2s at the press event. The steering system and network link (along other things) is really revolutionary.

      Greg
    1. Scream And Fly's Avatar
      Scream And Fly -
      Quote Originally Posted by DanUmbarger View Post
      Great read Greg, can't wait for part2...Thanks
      Thank you so much Dan! Part 2 is really where most of the content will be.

      Greg
    1. Scream And Fly's Avatar
      Scream And Fly -
      Quote Originally Posted by baja200merk View Post
      Nice job good read

      Quote Originally Posted by CRH1 View Post


      Looking forward to part 2
      Thank you so much guys!

      Greg
    1. Knut74's Avatar
      Knut74 -
      Read this and really enjoyed it. Very well written Greg, can’t wait to read second part! Good job!
    1. SALSTRIP's Avatar
      SALSTRIP -
      Absolutely the best article I have seen on these engines , can't wait for the G2 info in Part 2.Thanks for posting it up its Awesome
    1. Laker's Avatar
      Laker -
      Fantastic Virus!!
    1. Scream And Fly's Avatar
      Scream And Fly -
      Quote Originally Posted by Laker View Post
      Fantastic Virus!!
      Thank you so much buddy, I appreciate it very much! I knew you would be reading this for sure.
    1. powerabout's Avatar
      powerabout -
      great stuff
      first time I have read anywhere the difference between a ficht injector/emm and an etec version.
    1. Knut74's Avatar
      Knut74 -
      When is Part 2 due? Can’t wait to read it.....
    1. JP Love's Avatar
      JP Love -
      Verry nice reading... Art of engineering.. Thank's S&F..
    1. JP Love's Avatar
      JP Love -
      Best technical infos from old and G2 systems...