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Engine won’t stop

Category: General Tech Discussion 3 months ago

 I have a 912 ULS. Today when I did my mag check, the right mag did not drop. The left mag work properly.  After that I tried killing the engine by turning off both mags and the ignition switch. The engine kept running. I had a friend chock the plane and then I removed the mag switch. Nothing changed, the plane kept running. I then disconnected the fuel line and the engine died. 

 Any suggestions on where to start looking for my problem? 

  • Re: Engine won’t stop

    by » 3 months ago


    Your Right Mag switch is NOT connected to the engine ignition coil.

    If the Switch OR the Wiring fails, the engine will keep running.

    The switch could be bad.

    The wires on the switch may have become disconnected or corroded.

    The connector on the engine ignition Coil may have become disconnected or corroded.

    The wires from the switch to the Ignition Coil may be severed.

    The simple explanation of how the MAG Switch works it that it Shorts Out the Points to kill the ignition.

    If the switch does not have continuity to the Points, it can't short them out and the engine keeps running.

    These are the only switches on the panel that are mounted upside down.

    Switch DOWN = Switch ON = Ignition OFF.

    - - -

    Removing a MAG Switch will definitely keep the engine running.

    You needed to short the wires together to kill the ignition.

     

     


    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    whertzel1@yahoo.com
    Clicking the "Thank You" is appreciated by all.

    Thank you said by: RotaxOwner Admin

  • Re: Engine won’t stop

    by » 3 months ago


    Thanks for the explanation.  I disconnected the wires from the mag switch and touched them together.  The engine kept running.  After that didn’t work, I cut the fuel off and the engine died.


  • Re: Engine won’t stop

    by » 3 months ago


    That probably means the problem is at the engine end of the wiring.

    - - -

    You initially said you "Disconnected the Fuel Line". 

    Do you have a fuel Shut-Off Valve?


    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    whertzel1@yahoo.com
    Clicking the "Thank You" is appreciated by all.

  • Re: Engine won’t stop

    by » 3 months ago


    Thanks.  I will the the P-lead going into the black box.  Hopefully I find a loose wire.


  • Re: Engine won’t stop

    by » 5 weeks ago


    Usualy wires in electrical systems gets broken near of connectors where there are an elasticity change.

     

    Disconnect connectors and perform a continuity test from switch to connector.

     

     


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