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912uls Oil In Exhaust

in 912 / 914 Technical Questions 7 years ago
2012 912ULS w/210 hrs total time running 93 Octane ethonal free.

I'm in the early troubleshooting stage.
Began after a normal oil/fuel filter and plug change. No contamination in any filters or magnet plug.
Engine ran rough at high RPM (above 3000). Mag drop ok.
Initial thought was fuel so pulled float Bowls. Bowls were perfectly clean. Noticed one float was sinking a little, weighed it at 5g, replaced it. Still ran rough at high RPM.
Pulled cowl again and noticed oil coming from the #1 cylinder exhaust. Pulled #1 cylinder plugs and they were wet with oil. Used an endoscope to look in the cylinder and detected oil bubbling up along the cylinder wall. Haven't done a differential compression test yet(bad gauge on a brand new E-2A).
Any ideas where to start?
Aaron
IMG_1577.PNG (You do not have access to download this file.)

  • Re: 912uls Oil In Exhaust

    by » 7 years ago

    Hi Aaron,

    You're doing a good start by doing a differential compression test. If the compression is bad time to pull the head and see what's going on with the valves or rings. If you have good compression then time to find out why the plugs probably aren't firing. The top of that piston may need cleaning.

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

      
    Report

  • Re: 912uls Oil In Exhaust

    by » 7 years ago

    Compression is good. Determined it to be a bad spark plug. Running well except now I'm getting a 300 rpm drop on the right magneto.
    IMG_1320.JPG (You do not have access to download this file.)
      
    Report

  • Re: 912uls Oil In Exhaust

    by » 7 years ago

    Usually a 300 rpm drop is a single plug or plug wire. Either change all those plugs and or unscrew each plug boot and trim the wire back 3/8", put a dab of dielectric grease on the end and screw the cap back on. My bet is one of these will fix your 300 rpm loss.

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

      
    Report

  • Re: 912uls Oil In Exhaust

    by » 7 years ago

    Thanks Roger, amazing support, thanks again.
    Will check the other plugs and wires.
    With the carbon deposits found on the pistons with the endoscope. If I pull the heads to clean them, you wouldn't happen to have all the gasket and o-ring part #s necessary to re-assemble the 912uls cylinder do you (I've got the cylinder alignment tool)? It'd be nice to have everything necessary to re-assemble instead of waiting weeks for parts while the engine sits on the floor in pieces.

    Aaron
      
    Report

  • Re: 912uls Oil In Exhaust

    by » 7 years ago

    Hi Aaron,

    With 210 hrs. I can't imagine you have hardly any carbon build up.
    Sorry I don't have any parts. You'll need to call a Service Center for "O" rings. If all you are going to do is pop the head off and clean the top of the piston then you really don't need much. There is no gasket.

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

      
    Report
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