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Hi I have a 2 year old 914, and I am constructing an aircraft so I was unable to run the engine for about a month. It had auto fuel in it.

 

Upon starting with the choke it idles around 2600 RPM and won't go any lower

Also when the choke is pushed in the RMP drops a bit and at a certain point the engine dies

 

The turbo also had some oil buildup in the air side from the check valve not sealing over time, not sure if that oil also contributed to this.

 

 

  • Re: Carb Issue

    by » one month ago


    Know nothing about 914's - suggest you work through Rotax recommended method for initial setting of the carburettors (see below).  From this initial setting, you should be able to make whatever adjustments necessary, to get the engine to idle satisfactorily - then move on to balancing the carburettors for best performance.

     

    Maintenance Manual Line

    Chapter 12–20–00 – SCHEDULED MAINTENANCE

    Fuel system ...........................................................................................................................................28


  • Re: Carb Issue

    by » one month ago


    The carbs were set and functioning correctly during previous runups with a normal idle speed.

    They seem basically identical to the 912 carbs. 


  • Re: Carb Issue

    by » one month ago


    I can only speak from 912ULS experience -

    My new engine, with "Soft Start", starts (when cold) almost instantly.

    Method;

    Choke full on (I use two plastic pegs on the choke button shaft) .

    Throttle fully closed (off).

    Start - within a second or so, the engine rpm rises to about 2500 rpm.

    Choke half off (remove one peg) .

    Choke fully off  (may be a further 2 seconds at most)

     Throttle open to maintain 2300 - 2500 rpm for warm up.

    I do not run my engine with choke fully or partially engaged, for more than 2-3 seconds in total.

    I do not bring my rpm down to 1700 (idle) until doing preflight checks (oil temp 50+C) 

     

    "The carbs were set and functioning correctly during previous runups with a normal idle speed."

    Sound like a control cable/rod may be sticking OR choke mechanism not returning - return spring missing?


  • Re: Carb Issue

    by » one month ago


    My 914 behavior is similar except for the high idle. I have to advance the throttle quickly and simultaneously while closing the choke or it dies every time. Check/drain the oil from the turbo if sitting for extended periods and use 100LL also, it’s more stable.


  • Re: Carb Issue

    by » one month ago


    Sam Purpura wrote:

    My 914 behavior is similar except for the high idle. I have to advance the throttle quickly and simultaneously while closing the choke or it dies every time. Check/drain the oil from the turbo if sitting for extended periods and use 100LL also, it’s more stable.

    Question, how long to you have to run the engine before this works?

    I just did a run where I left the choke on, the RPM gradually rose to 3,000

    It wasn't until about 4 minutes then I was able to turn the choke off and advance the throttle simultaneously

    After that the engine had normal RPMs / behavior


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