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There I was lined up ready for the ok from the controller at a very busy airfield in my 503dcdi powered trike,

I had been running at very low rpm waiting my turn to line up....engine prob been running for 20 mins waiting my turn,

I get my self lined up open the throttle and the engine stumbles and would not increase its RPM and quite lumpy with it...I abandon my idea of taking off and need to clear the runway,

I just about manage to get clear of the runway as there is a queue behind me...I think I then closed the throttle completely and opened it again and it was back to normal,

After a ground run of 5 mins and trying to keep the revs up....not easy as my single nose wheel brake is not that effective...all seem fine on both mags so I get airborne with without further probs,

I suspect some kind of flooding...what do you think guys....just to add...it was a very warm day at around 24c 73f...dew point was around 8c 46f.

Nick.
  • Re: 503 dcdi stumbling when going to take off power.

    by » 10 years ago


    Hi Nick,

    You just fouled and loaded up the cyl some. Engines run richer in the warmer air than they do when it is cold out. Then the higher revs cleaned it up and then you were ok. If you have to idle for a while waiting just try to do it at a higher rpm. How about looking into a better brake setup for your trike?

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


  • Re: 503 dcdi stumbling when going to take off power.

    by » 10 years ago


    Hi Roger and thanks you confirm what I was thinking....re the brakes...its a single small drum on the front hub...there never efficient and its not easy getting permission to modifie such things in the UK unfortunately,

    Very embarrassing place for it to happen to me though...lesson learnt.

    Nick.

  • Re: 503 dcdi stumbling when going to take off power.

    by » 10 years ago


    Nick,
    Try adjusting your idle jet mixture a little leaner (open). It'll help from loading up.

    By the book, fully warmed up, adjust the idle jet to max rpm increase (screw out), then richen just slightly (screw in). It's the small brass screw. Out to lean, in to richen.

    Dave

  • Re: 503 dcdi stumbling when going to take off power.

    by » 10 years ago


    I know the screw you mean Dave...I have tried in the past to get a smoother idle but I find its not easy to get the idle mix in sync with the DC engine....should I be able to achieve a shack free idle at 2000rpm,

    Mines not bad but the motor does shake a bit on its mounts...but good idea about leaning the idle mix.

    Nick.

  • Re: 503 dcdi stumbling when going to take off power.

    by » 10 years ago


    Hi Nick,
    Make sure your carbs are balanced and if your engine shakes too much then it may be the carbs causing the problem and it may be weak or old engine mounts. If the rubber mounts are 5 years old toss them and replace them. If you aren't sure about how to get a good balance it is explained in the maint. manual.

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


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