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Eco mode throttle position

in 912iS Technical Questions 6 years ago
I read in the manual that the engine should stay lean until about 95% throttle. Me egt drops and my fuel consumption goes way up at about 70% throttle. Is this normal, is there an adjustment for this?

My fuel flows tend to be 10-20% higher than book values at a given rpm and manifold pressure.

Thanks.

  • Re: Eco mode throttle position

    by » 6 years ago

    Usually if you stay down around 5200 or lower you're good. Run at 5300 plus and you'll consume that extra fuel. No adjustment. For the most part everything is computer controlled.

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell

      
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  • Re: Eco mode throttle position

    by » 6 years ago

    The engine selects ECO mode based on Manifold Pressure (MAP) and RPM. Power!
    You should be able to maintain ECO Mode up to 900mBar(26") below 5500 rpm.
    If you are seeing, for example, 27" or more at 5200rpm, you are Over Propped and lugging the engine.
    The engine goes into Power Mode to save itself.

    At Wide Open Throttle (WOT), can you make 5500 rpm in a climb, and 5800 in level flight?
    Reducing the prop pitch will increase the RPMs and lower the MAP.

    The engine will last much longer if you do not over stress it.
    It will reward you with lower fuel consumption.

    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    Clicking the "Thank You" is Always Appreciated by Everyone.

      
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  • Re: Eco mode throttle position

    by » 6 years ago

    Hi Bill,
    The guys in the US use ground adjustable props and probably none of them see 5800 rpm and especially at take off. Most only see 5500 to 5650 at WOT in level flight and of course less in climb. Usually around 5000 - 5100 in climb. I have 6-7 912iS owners I see and because of their ground adjustable prop settings 5300 is their magical number.
    I agree it would be nice to be able to use a variable pitch or constant speed prop to be able to get the full benefit of the engine, but we're stuck here in the US.

    p.s.
    He lives in Idaho so he's most likely has a ground adjustable prop.

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell

      
    Report

  • Re: Eco mode throttle position

    by » 6 years ago

    Roger, is the 5300rpm at static run-up or during an in flight condition?
      
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  • Re: Eco mode throttle position

    by » 6 years ago

    I agree with Bill, but we're stuck.

    In level flight. Not static.
    It's unfortunate we're stuck with a ground adjustable prop. It would be nice to fully utilize the full capabilities.

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell

      
    Report
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