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When my 914 was brand new needle position was #3 on oneside and #2 on the other. Fellow LAME (licensed aircraft maintenance engineer) thought Rotax had made a mistake and made them both even. Subsequently have found this is done by Rotax to counter difference in temps between cylinder banks.

Problem is - I cannot remember which side was what, it is somewhere in the documentation but have been unable to locate this information.

Would like to try the needle positions as originally set by Rotax. Guidance as to what side has what needle position would be appreciated.

Cheers and thanks
Peter Armstrong
Auckland, New Zealand
  • Re: Offset Needle Position on 914

    by » 13 years ago


    Do A topic search on needle positions. I have posted that chart on one of the topics.

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


  • Re: Offset Needle Position on 914

    by » 13 years ago


    On a 914 engine, the needle jets are set at the factory with the 1/3 carb at position #2 (2nd leanest) and the 2/4 carb set at position 3 (2nd richest).

    The reason for this is the 914 turbo charger feeds the compressed air into the air box via the elbow on the 1/3 side of the air box. Since air likes to take the easiest route, the 2/4 carb gets a little more blast of air than the 1/3 carb. To compensate for this and even out the temperatures and fuel air ratio between the 2 carbs, the factory sets these needle jets staggered.

    This info can be found in the Heavy Maintenance Manual Chapter 73-00-00, Page 28.

  • Re: Offset Needle Position on 914

    by » 13 years ago


    Thanks guys appreciated, will change back to standard recommendation.

    Cheers Peter

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