912UL hasn't run for a year.  Tried and no luck starting.  I have cleaned all the grounds and there is still no spark. I checked this by cutting a plug gap down so it could be seen from above. Then put a tube over the plug to make it dark by the electrode.  I checked it on an engine that runs and could see the spark.  No idea why both ignition systems would fail.  

  • Re: 912UL no spark

    by » one year ago

    Other than NOT running it for a Year, what HAS been done to it since it last ran?

    What ignition modules do you have? How many Six, Four, and/or One Pin connections are there?

    The first place to look will be the BROWN WIres going to the Ignition Kill (MAG) Switches.

    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    Clicking the "Thank You" is Always Appreciated by Everyone.

  • Re: 912UL no spark

    by » one year ago

    One of the common failure modes of the ignition modules is not to produce a spark at cranking RPM. Sometimes heating the modules with a hairdryer or hot air gun is sufficient to get them working again. It is a quick test and then you would know if this is the issue.

    If that doesn't work then there are a number of other things to check:

    1. Grounds from module and coils to the crankcase.

    2. Make sure that the kill switches measure open and closed at the module.

    3. Check the coil resistances from the module connector to:

        a) the charging coils (red wire).

        b) the trigger coils.

    4. Check the position and gap on the trigger coils.

    5. Measure the voltage on the red wire during cranking.



  • Re: 912UL no spark

    by » one year ago

    Do the cheap and most common things first to rule them in or out. 

    If this hasn't been done then I'd do it first. If the engine doesn't turn over fast enough the the CDI ignition system won't generate enough power to cause the spark. The engine may be just turning over too slow. This isn't a standard magneto setup. I would either replace the battery or jump it to make sure I had enough rpms to generate the power you need to start. I

    If it was running before it just sat then the battery could easily be the culprit. Plus if it was running then who or what caused a wiring issue? Plus spark plugs could contribute to your issue if the battery is weak and your plugs are gapped too wide.

    Plus since it sat so long clean the idle jets out. I'm sure they're clogged.

    f this gets ruled out then follow the other trouble shooting comments in previous post.

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

  • Re: 912UL no spark

    by » one year ago

    Dear Clyde,

    I am the owner of a 912 UL. Brand new without any problems. Why I answer? The reason is I will learn (maybe in the future I will be in the same position like you) and I will help others. My expereance is that you know all the relevant issues and you need help but it is in your mind that all the helpers in this forum cannot read your mind?

    So if you give us the relvant informations, it is much more easier to help you. So for my understanding: Are you sure the engine run well before? Are you a witness for this? Are you the owner? Why don't run the engine not for a year? Where was the engine/aircraft stored? Dry conditions, wet conditions, outside? Are there any damages esp. at the cables (marten bite or so on)? If you try to start can you smell the fuel?

    Yes, i perseived your information about the spark. If you sure that it is really a ignition problem? Give us the information that you try everything to narrow the cause. If you the owner, if you sure the engine run well before, if you sure the battery is stronge enought, if you sure the fuel passed the carburators in a right way, if you sure the compression is wel, if you sure the wiring is OK (includin maste swich or so on)l so I agree with you the ignition modules are fail.

    If both ignition modules are fail (with one sound ignition module the engine will start) find the wire which support the both ignition modules with power. Is power (enough volt) at this cable? If not maybe the generator fails. If if if ... There are good ideas from the responsers of your question but without the informations they needed you must have outstanding luck to find the needle in the haystack.

  • Re: 912UL no spark

    by » one year ago

    So far I have checked all the resistances as outlined in the heavy maintenance manual.  Replaced all the spark plugs.  Attached my Dr. Rotech electronic engine analyzer and all of the checks the analyzer does come up green.  This includes checking the trigger coils, the primary and secondary coils, the stator, the battery ground and the proper wiring of the ignition switch.  No failures were noted.  The only thing the analyzer doesn't check is the ignition module.  So I iced it down and still no start.  Sooooo....I conclude the only thing it could be are the modules.  I have a friend that is sending me his spare module to try.  I will let you know the results. 

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