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Oil burping of my 912ULS takes much longer and significantly more effort than on my 914.

Could I safely avoid all the manual effort and achieve the same result by spinning the starter for a few seconds (mags off of course)?

Or would the oil not return to the canister using the starter?

  • Re: Oil burping with starter

    by » 5 months ago


    LOL my 912iS can take 30+ turns....I take it as an opportunity to mentally settle down and focus on flying...also cheaper than a GYM membership.

     

    Having said that I have friends that do as you say and it seems to work, I have another whom has never burped his Rotax in 30 years and has never had a problem so....

    But I like to feel the engine the compressions and lubricate everything before the start, it gives me some confidence in the engine


  • Re: Oil burping with starter

    by » 5 months ago


    Don’t know how hard that would be on the starter.  On my 912uls burp is about 30 blades.  That is a lot of starter time, since my starts are usually only 3 or 4 blades before the engine catches. I think of it as a ritual.  


  • Re: Oil burping with starter

    by » 5 months ago


    When the oil is warm I turn the prop to max compression, hesitate for 5 seconds turn to next top compression, hesitate for 5 seconds . I never have to turn more than 5 blades. 


    Walt

    my blog; waltsrv12.com


  • Re: Oil burping with starter

    by » 5 months ago


    There are reports in the dustbin of 912 ULS history of hydraulic lock caused by oil seeping into the cylinders - folklore or legend, I don't know but I'd stay with the manual option for all of the reasons previously stated (and, the stories may not be legend).  I've noticed that fewer blades are needed if the prop is turned more slowly which might mean more blades will be needed if turned as fast at the motor turns the engine.


  • Re: Oil burping with starter

    by » 5 months ago


    All great responses. To add my experince:

    My 912ULS is quite new, just over the 80 hrs, which may help with the time/effort needed to achieve sufficient crankcase pressure to force the oil out into the oil tank.

    If I go slow, & pause at each Max compression, it takes about two full revolutions of the prop for the first Gurgle/Burp.

    I suspect that oil tank position, as related to crankcase, may also have an effect on Burping (see Rotax  Installation Manual, Chapter 79-00-00, Oil Tank, Permissible position and location, Pages 19-21

    John, If changing your technique and the position of your oil tank is okay and there has been no reduction in time to Burp, I would consider doing a Compression Leak Down Test.


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