My RV-12's 912ULS used 1/2 to 2/3 liter of oil in the first 25 hours and has used at list that much in the next 35 (59.1 hrs). I'm using Shell Sport +4 and oil temps this supper have been 220-230 deg. Everybody says the 912 doesn't use oil. Is this within normal range and how do I ask someone at Rotax? I think it's burning it-- the inside of the exhaust pipe is black and sooty.


Wayne 120241/N143WM
  • Re: Oil Consumption

    by » 13 years ago

    Hi Wayne,

    Your Rotax 912 absolutely shouldn't be using oil. First I would suspect a leak that you may not know about. If you know for sure you have no leaks, that the high pressure and high flow air isn't blowing leaking oil off the engine then it's time to do a leak down compression test like you would during an inspection. Look up inside the exhaust pipe for oily residue. Check the plugs for clean burning. Most pilots never add oil in a 912 between changes. On a leak down test using 87 psi as a test pressure I would expect to see 84-85 residual (80 psi test pressure then a residual of 77-78 psi). This needs to be done on an engine that has been warmed up to operating temp (i.e. 120F+ oil temp)
    Without knowing anything else I would still bet on a leak. It is extremely rare to have a bad 912 engine eating oil.

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

    Thank you said by: Wayne Moyer

  • Re: Oil Consumption

    by » 13 years ago

    If you happen to be doing any sort of 0 or slightly negative G manoeuvres to impress the girls, the oil will pour out the vent tube that attaches to the top or the oil reservoir.
    not saying thats the problem, but one of many possibilities.

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