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Climbing at full throttle 912is after about 1 hour flight and than really rough running and rpm dropped to 4100 still at wide open throttle (WOT). Reduced throttle to idle and OK. Back to full throttle bad vibration and only 4100 rpm. All gages norma, 1 and 3 EGT slightly lower but nothing unusual…... Landed, shut down, restart, systems check, all ok. Takeoff power ok for about 5 seconds than same problem,  rpm drop and bad vibration. Landed, tried again 2 more times and same - full throttle ok for 3 to 5 seconds than rpm drop and bad vibration.

Pulled off runway, pulled cowl off, wiggled every plug, electrical connection, fuel injection wire twice. Started up ran fine all the way home 40 minute flight.

Down loaded with BUDS dongle and nothing for the ECU time of the flight. No warnings, faults, nothing. 

Thinking back, I should have shut off one lane while flying to see what happened. 

Next step is to fly with the BUDS system to look for any thing in the engine health screens and shut of lanes individually if the problem happens again.

Any thoughts, experience?

  • Re: Intermittent rough running and RPM drop

    by » 4 months ago


    I don't have any advice other than to be careful.  Hopefully some of the tech guys on here can help you. Good luck and keep us informed.

     


  • Re: Intermittent rough running and RPM drop

    by » 4 months ago


    It's difficult to say at this point; however, I would like to see the data contained within your ECU. It may be possible that you had a loose connection and after wiggling plugs and wires it fixed itself? Let us know if you see anything when you fly with the BUDS system and if you want, you can send us the ECU data file and we can have a look.


  • Re: Intermittent rough running and RPM drop

    by » 4 months ago


    Rotax-Owner wrote:

    It's difficult to say at this point; however, I would like to see the data contained within your ECU. It may be possible that you had a loose connection and after wiggling plugs and wires it fixed itself? Let us know if you see anything when you fly with the BUDS system and if you want, you can send us the ECU data file and we can have a look.

    As I said above, after I looked at the downloaded data, there was NOTHING for the time period of the event, otherwise I would have had something to go on.

     


  • Re: Intermittent rough running and RPM drop

    by » 4 months ago


    Update. Hooked up buds system and Went out to test fly this morning. Quickly  going to full throttle, could only get to 4300 rpm. No friction above 4300. BUDS system showed partial position correlating to rpm. Slow advance idle to full no problem. Back to the hanger and turns out advancing to full throttle the arm connecting the the throttle was sticky and not going all the way to full throttle. Some lube and it functions great. Word to the wise, great place to lubercate that throttle valve spring area.

     

    However this does not explain the previous problem of rough running. Running great now……

    We are keeping it within gliding distance now for a while.


  • Re: Intermittent rough running and RPM drop

    by » 4 months ago


    Paul Hamilton wrote:
    Rotax-Owner wrote:

    It's difficult to say at this point; however, I would like to see the data contained within your ECU. It may be possible that you had a loose connection and after wiggling plugs and wires it fixed itself? Let us know if you see anything when you fly with the BUDS system and if you want, you can send us the ECU data file and we can have a look.

    As I said above, after I looked at the downloaded data, there was NOTHING for the time period of the event, otherwise I would have had something to go on.

    I should have added to this. Yes I was expecting to see something in the BUDS data to point me to the loose connection system  so I could focus on that system but nothing on BUDS.

     


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