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Rough Running.......need help.

in 912 / 914 Technical Questions 10 years ago

  • Re: Rough Running.......need help.

    by » 10 years ago

    I think it would be a waste of time and money to take it apart. Unless it is making metal or the crank is bent?
    -You can do the crank distortion test (see video) to precisely measure the out of round.
    -Check the magnetic plug and cut open the oil filter to check for metal.
    Have you balanced the prop? checked prop tracking?
    Rob
      
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  • Re: Rough Running.......need help.

    by » 10 years ago

    I also am scared of spending much money and motor is found to be good.
    I have not tested crank is round.
    Magnetic plug is clean, oil filter paper is clean of metal.
    Prop is good static balance and motor is rough at same speed when run with prop removed.

    Thank you for your suggestions Rob.
      
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  • Re: Rough Running.......need help.

    by » 10 years ago

    Is the nose wheel fairing loose? True story I heard from the factory: many many hours spent troubleshooting vibration in new engine (I don't recall the aircraft type). Put the old engine back in and the vibration disappeared! put the new engine back in and vibration came back! how strange, what happened? Answer: the wheel fairing was not re-installed when the old engine was installed but it was installed again for the new engine. removed nose wheel fairing and vibration is gone.
      
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  • Re: Rough Running.......need help.

    by » 10 years ago

    Hi Rob,

    I have had a half dozen or so Flight Design owners tell me they had some rough running on take off. It was just the front tire out of balance.

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

      
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  • Re: Rough Running.......need help.

    by » 10 years ago

    Well,
    I have done a lot over the last week to try to resolve this issue. I found that my radiator was somewhat flexing so I made a bracket to make it more secure. I also loosed all my rubber mounts as 2 of them were tightened until they bottomed out. The barry mounts adjustment made the most difference. But I still have the vibration.

    The visual vibration has not changed at all, but what I can feel has ( I attribute this to the motor mounts). I am still baffled as to why the vibration is in this rpm range 4500-5300. I am attaching another video I took this morning as you can see the vibration increase with rpm and then decrease when rpm nears 5300. This really makes me think it is in the carbs.

    Travis

    https://www.youtube.com/watch?v=01sTeHHUGSw&list=UUaJg4CalA-Yo5UzgrrsM8Jw
      
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