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Hi all,

Apologies for yet another EGT question in the fourm but I've had a good search and general read around and I am still confused.

I've got a reoccuring EGT alarm (900c+) from cylinders 2 and 4 on the flydat that only occurs during power descent (RPM approx 4600-5000). 1 and 3 stay below alarm limits and all remain below 900 in the climb/cruise. Engine is a older 912 with 900hours. It lasts long enough for me to notice (30secs-1min) but drops when i raise the nose and airspeed bleeds off.

I first noticed this a few weeks back in a descent  when the OAT started getting colder (Uk based) so not sure if that has something to do with it. Carbs have been overhauled a few months back, new spark plugs this week and new floats and carbs synced using carbmate alongside changing fuel filter etc. Temp probes seem to be working ok and as I said it happens on both at the same time with no obvious rough running.

I only use Ul91, normal K&N filters.

I know some people don't read too much into EGT's but welcome any thoughts as I'm a little stumped. Maybe it's something, maybe it's nothing but I don't think I'm flying the aircraft any different the last few weeks that would easily explain away the alarm so would appreciate any thoughts.

Thanks all.

  • Re: EGT alarm in Power descent

    by » 9 months ago


    If the carbs were rebuilt a few weeks back then you may want to check to see if the needle clip is in the #3 slotted position or the #2. The #2 runs leaner. The 4600 rpm area runs leaner than rpm's above 5K. So check the carbs and you could also stay below the 4600 rpm are and above 5K. Make your powered approaches let say at 4k - 4200 rpm. Just food for thought.


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


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