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Contaminated Fuel

in 912 / 914 Technical Questions 12 years ago
Rotax 912UL - History: 350hrs: 200 ltr Drum of fuel delivered. Aircraft tanks almost empty. Filled with fuel from drum. Flew aircraft for 3.1 hrs. Everything OK. Next pre flight and noticed oil was approx 250 ml over. Drained oil and refilled to correct amount. Another 3 hr flight and again about 250 ml of oil too much on next pre flight. Drained oil again and another flight endurance 2 hrs. Checked oil after flight when engine had cooled and it was about 200ml too much. Checked every component likely to cause this growing oil enigma. No sign of leaks anywhere. Took sample of fuel and tested with blotting paper against a new drum of fuel. Paper sample from the aircraft stayed wet and oily. Sample from new drum was dry in a matter of minutes. Sent sample of fuel for analysis and result was contaminated fuel. Suspected distillate (diesel fuel). Drained aircraft tanks, drained oil and changed filter and oil. Filled tanks and flew for 3 hrs. Problem resolved.
Everything seems okay and it is running better than ever.

Does anyone here know if any damage may have occurred to the 912UL? :S

Thanks

  • Re: Contaminated Fuel

    by » 12 years ago

    Same hapends to our plane Tanktruck was not cleaned after diesel delivery. We do the same cleaning as you and after that engine running with no problem We have two plane one Rotax 80 hp and one 100hp
    I heared abt in Germany this allsow hapends.some times.
    Good flights
    keb from Aland isles in Finland
      
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  • Re: Contaminated Fuel

    by » 12 years ago

    Hi Frank,

    You should be okay especially with the lower compression UL. Nothing to do at this time, but keep an eye on things.

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

      
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  • Re: Contaminated Fuel

    by » 12 years ago

    Hello,
    Is it strange that the plugs were not fouled due to the diesel ?
    I take it, the diesel was getting past the rings ?
    Regards,
    Rhett Mitchell
    Australia
      
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  • Re: Contaminated Fuel

    by » 12 years ago

    To Rhett
    The plugs were the last thing we thought about checking when we did a leak down test. The plugs were wet, and yes most of the diesel was not burning but getting by the rings. But as I say the engine appears to be running better than ever. I don't think any damage has occurred, though had we let it go we may have had blown seals.
      
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  • Re: Contaminated Fuel

    by » 12 years ago

    Here in Italy, summer 2010, at the club we have 5 planes running on 912ULS different age, diferet brand. The oil level did start to rise on all, one after the other. It took sometime to figured out whot the problem could be, but at the end the only thing the were sharing was the refuelling station.
    We sent a simple to be cheked , the answer was : 13% of diesel in it. Still figting with the fuel company......
    It's not very clear to me why diesel is passing under the piston rings ( or maybe the hole contaminated fuel) un complete explosion? whot else ?

    Since april on the new edition of the OM rotax is stating that one of the possible cause og oil level rising is diesel contamination......to late for us.....
    I am shure some tech can explane whot happening

    ciao
      
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