John912ULS

Hi Skippydiesel, Thanks for your kind message. I haven't been to the aircraft yet as I work in the UK and my plane is in Ireland. I'm flying back at the end of the month to try some of the recommendations posted here Kind regards, John

Thanks- actually this very thing was told to me by a respected Rotax maintenance engineer here in Ireland over the phone also today Pardon my ignorance but would you be so kind as to explain how exactly I can find this. I'm given to understand it's a 10mm head nut somwhere close to the CDIs? Kind regards, John

Thanks Blueadventures, I am trying to find out who that is :-)

Go raibh maith agat, Skippydiesel, an Éireannach thú? Yes, I tried the mag check at higher RPMs, same large drop and rough running unfortunately. Regards, John

Hi Downunder, Thanks for your reply. Yes, I've bought 8 plugs and I'll change them all and see what happens. John

Hi Kyle Communications, Good point. Yes. It's doing it at higher RPMs also. It's very strange that they are both doing it. An engineer I know says he has encountered two cases of both CDIs failing at the same time. Odds must be very high on that. I pulled all 8 plugs out and inspected them- they were all a normal healthy colour with minimal deposits or signs of either fouling or hot running. I'm going to changed them anyway just to be sure. I'll gap them first, of course. Thanks for your help, John

Dear friends, My engine, a Rotax 912 ULS, has started running roughly on each mag. Aircraft; UFM-13 'Lambada'. Year of Construction; 2006. Total hours; 530. Previously it would always drop approx 150-180 RPM on each mag. Now, however, it's dropping over 500 RPM on each mag and running roughly with considerable shaking and roughness. It runs normally on both mags. PLEASE SEE VIDEO, ATTACHED Spark plugs seem unlikely as they only have 29 hours on them since being gapped and fitted last year. I changed the fuel to fresh, quality fuel and that didn't' change anything. There's a lot of gents on here posting about the CDI modules giving trouble. It's €400 to overhaul each one at Carmo, Netherlands if I have read correctly. If anyone might be able to offer some advice which might see me resolve this less expensively I'd be very happy to hear from you Kind regards, John. PS: Is there any risk of the spark plugs failing to spark when I'm flying? I have been advised that the design of the ignition system offers the same level of redundancy of a classic magneto (whereby the spark will still be supplied to the plugs regardless of any ignition and/or battery problem) and therefore my CDI problem is only a startup problem -is this in fact the case? VID-20190726-WA0014.mp4