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I just had my first start of my 912iS Sport and it didn't go well.  Started right up but ran terribly rough and I shut it down after about 10-seconds.  Pulled the cowl and checked all the spark plug connections because it feels like maybe only 3 cylinders are firing.  Performed another start and same extremely rough run.  Again I shut it down around 10-seconds.  Too nervous to try again thinking I'm going to grenade the thing.

I've verified oil pressure by hand cranking as well as verified oil had been returned to the oil tank priot to start.  Thinking tomorrow I'll pull the plugs and check for fowling and that I have a spart at each cyulinder, although I'm not exactly sure how to do that last one.  Will read up tonight and see what I can find.  The whole engine felt out of balance, it that makes sense to anyone.

Oh, I also am adhearing to the latest starting guidlines by having the throttle set to just over 50% and the EMU shows green.  After reading other posts, I'm wondering if I should have opened the throttle up to closer to 70%???

Any recommendations and/or guidance would be greatly appreciated.

Thanks.

Tim

  • Re: Rough First Start

    by » 3 years ago


    Not sure where this 50% came from I always start mine at about 5-10% so it idles at 2200 rpm. Never had a difficult start. I just did my 700 hr service still original compression does not use oil between 100hr changes.

     

     

     


  • Re: Rough First Start

    by » 3 years ago


    The latest Operator's Manual (June 1st, 2019) states, "Put throttle between 1 to 2 cm throttle opening (correlates with 55%-65% throttle valve opening)."

    My ECM indicated about 55% throttle when I started.  Both times I immediately throttled back, which might account for the engine not smoothing out.  I was caught off guard by the rough run and jerked the throttle back to idle pretty quickly both starts.  Nervous has heck to try a third time...

     

     


    Thank you said by: Glenn Martin

  • Re: Rough First Start

    by » 3 years ago


    I had a similar problem on my first iS engine start. Turned out to be blocked fuel injectors. Dean Vogel @ Lockwood Aviation quickly diagnosed my issue and helped me through the procedure to clean the affected fuel injectors. No further problems

    Good Luck,

    Gary


  • Re: Rough First Start

    by » 3 years ago


    Hmmm...  Was it an easy process?  I was going to try another start this week if I get a break in the weather but now I'm wondering if I shouldn't do that for good measure.  Thoughts?


  • Re: Rough First Start

    by » 3 years ago


    Rob Seaton called me this morning and helped further put my mind at ease.  Very generous and thoughtful of you reaching out, Rob!  Thanks for the awsome support!

    After Rob and I chatted a bit on the "interesting" starting behavior of the 912iS, and since the engine has sat for some time, Rob recommended I pull the injectors and send them out for cleaning, which is what I did today.  After I get them back in a week or two, I'll perform another start and see how it goes. 

    Think I can sleep more comfortably now... ;-)

    Also, a big thanks to others who have responded to this post.  Not sure what I'd do without the Rotax-Owner and Zenith forums.  Asked the wife (I mean Santa) for a paid membership in my stocking this year.  With another month or so to complete my build and begin taxiing, I know I'll be relying even more on this forum and the fantastic asistance it provides.

    Happy Holiday's everyone and thanks again!

    Tim


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