Seasons greetings & I plan to be flying on solstice   : } 

So I see yet another thread on burping, ha if it werent for burping & sinking floats ... this foro would wilt !  j/k

It is amazingly difficult tho., to figure out how to post a post, i have just the nondescript grey button way up & away from the threads ... 

Anyway, many of us were under the impression that burping was requiered to clear the engine of oil & air for the first few compression strokes ... not true, ive learned here   ... but this air in the engine scenario needs a stand alone thread.  Ive learned reversing the prop is a big no no,  I think ive read here that we should not hand prop the last of the oil w/ the oil filter off. I think ive read here that the oil cooler should not be drained during a oil chng.  In my installation, the oil cooler is well above the oil tank, so i assume it drains.  I think ive learned any suction of air into the engine is not good & will require a "purge". 

Well what about the suction occuring during compression testing or finding top dead center ?

With the oil system open to the environment via the overflow line, isnt the inside of the engine equal to the external pressure ?

Hopefuly one of our gurus will take time to educate some of us.

Heres hoping 21 is much better than this, one of the worlds worst years in modern times.  I'm greatful my own life was buffered for the many impacts, hope yours were too ...i'll leave w a view down @ phx sky harbour ;1'st time ive flown in class b,  not gonna try that again  :p




Roger, when this damnvirus abates, i hope you hold another basic class, clearly i need it!


8411_1_KPHX on the VFR Transition.jpg (You do not have access to download this file.)
  • Re: Air in engine - burping

    by » 3 years ago

    ...shoulda linked this :   https://www.rotax-owner.com/en/912-914-technical-questions/8407-spinning-prop-with-plugs-out

  • Re: Air in engine - burping

    by » 3 years ago

    "Burping" ... Clearing the sump of residual Oil to produce a true Oil Level Measurement.
    "Purging" ... Filling the Oil system from the Oil Tank to the Oil Pump  and "Priming" the Oil Pump.

    Rocking the Prop or turning it in reverse a half turn is not the end of the world. No action needed.
    There is no need to attempt to get every last drop out during an oil change.  Overkill!
    Drain the Oil, Clean the tank as needed, Replace Filter, Refill, Burp until Oil Pressure indicates, Done!
    There is no need to Purge with compressed air unless simple hand cranking fails to show oil pressure.

    After any activityy that effects the Oil system or rotation of the prop,  just hand turn the prop intil you see oil pressure.
    ANY pressure at all, confirms that the Oil pump is primed and the Oil Filter is full.
    On the first start after maintenence, watch the Oil pressure closely it should be above 15psi within 5 seconds and stable in 10.

    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    Clicking the "Thank You" is Always Appreciated by Everyone.

    Thank you said by: john gunn

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