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RPM drop with a 914 above 100%

in 912 / 914 Technical Questions 12 years ago

  • Re: RPM drop with a 914 above 100%

    by » 11 years ago

    Carlos, I found the following issues during the debug of this problem:
    - Debris were located in the hoses before the fuel pumps due to a hole in the gascolator grid
    - The rubber between the manifold and the carbs were not hermetic, so I replaced them
    - The carbs were replaced - not willing to wait for the older ones to be overhauled

    That solved my issues.

    Jacques
      
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  • Re: RPM drop with a 914 above 100%

    by » 11 years ago

    If you believe it is a full issue and you have found debris and cleaned it, but still have an issue then the whole fuel system may need to be cleaned.

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

      
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  • Re: RPM drop with a 914 above 100%

    by » 11 years ago

    Thanks for the answer,
    Well, fuel filters and gascolator were checked.
    In fact the gyro is new, with 250 hours total time since new, with the 914 as well new.
    All OK from factory, never a problem.
    I am worried because the the trouble I have, with the loosing of 1500 rpm at 100% power, sea level, it is always there, in all tests I do.
    At 100 % power I have only 4500 rpm, but the main point is that always it collapses in the same point and drop to 4000 revs. Is not randomly failing and not, it fails always.
    I realized the problem last flight, low power at take off, but I could manage to level and fly back and land.
    Since then, months ago, just couple of aborted take offs, and 7 hours of land engine checkings without success. I have a private short airfield, close to Mediterranean Sea, and....well, with 4000 Rpm, ...no way to climb.
    Even the turbo, I don't really know if it should go on or not...

    I will go over carbs, again.

    Thanks for helpful ideas.
      
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  • Re: RPM drop with a 914 above 100%

    by » 11 years ago

    I would disconnect the fuelline from carburator and check the quantity of fuelflow you have with 1 fuelpump running. As you know, the r914 needs maximum about 33 l/h with full power, you should have about 80 l/h to be on the save side.
    Karl

    Karl (Charly) Kistler
    HB-YPL(RV12iS) / HB-YNB (Helicopter CH7)
    karl@kistleronline.ch
    www.kistleronline.ch
    www.chaletferienfurna.ch

      
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  • Re: RPM drop with a 914 above 100%

    by » 11 years ago

    Hi Karl,
    Disconnect metallic pipe coming to every carb, and measure fuel flow in each pipe, switching on fuel pump?
    Is this what you propose ?
    So, you think can be one fuel pump not working well?
    Thank
      
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