Hello -first post here!

I have recently purchased a Tecnam p2002 with a Rotax 912s2 engine. Engine has reached 2000 hrs and been extended twice - we are currently around 2300hrs. Recently I've had an issue with the aircraft no developing full power and running a bit rough / vibrations. 

First time I noticed this was after a 50 hr check, run up was normal but just after rotation, power dropped from 2200 (FP) down to around 1900 - landed back on runway. Did another power check including full power stationary and a high speed abort and couldn't replicate. Tried another take off and same thing happened. Mechanic changed the spark plugs and checked the engine and all seemed ok. 2 days / 5 hours flight later, we had a reduction of power to around 2100 when in flight and some vibrations, this was improved instantly when carb heat selected and even after 5 mins of carb heat, vibrations returned if we put it cold.

Back at the field and another run up attempt resulted in 1700-1800 max with significant mag drop. Fuel is good, compressions are good and mechanic has found no sign of split /loose hoses etc. 

Any ideas where to look next?

Thank you.

  • Re: Carburetor/power problems 912s2

    by » one year ago

    I would look at:

    1. Debris in carb float bowl.

    2. Heavy floats.

    3. Fuel level in bowl.

    4. Bowl vent line open end positioning.

    5. Slide assembly rubbing?

    6. Starting carb (choke) mechanism problem (blockage, leak, not closing fully).

    Good luck!

    Thank you said by: Ian Palmer

  • Re: Carburetor/power problems 912s2

    by » one year ago

    Re choke we also note that applying choke during run up improved vibrations and results in less significant mag drop, as does carb heat. 

  • Re: Carburetor/power problems 912s2

    by » one year ago

    Choke and carb heat both richen the mixture. Since those improve the symptoms, perhaps there is a restriction causing lower fuel flow. Since the symptoms are intermittent, I would not think the fuel filters would be the cause. Since the engine runs rough instead of dying, I would suspect one carb. A previous responder mentioned debris in a float bowl.

    Although I have decades of engine troubleshooting, I am new to the Rotax 912 and do not recognize the symptoms caused by the electronic ignition boxes. 

    Good luck.


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