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Severe Jittering Oil Pressure

in 912 / 914 Technical Questions 9 years ago

  • Re: Severe Jittering Oil Pressure

    by » 7 years ago

    Hi Roger

    I have heard rumours that the mushroom type can lead to misalignment and eventually this will wear off and can produce metal fragments that will eventually damage the oil pump someone mentioned this already above in this thread.

    BTW: I removed the oil pressure gauge an I found out the nut holding the earth to the body was loose! I have now used a locking nut and test benched the gauge according to the ohm’s chart. It’s spot on.

    So that is now out of the equation!! Due to weather I did not test fly but I am confident that it was the culprit for the jittering.. will keep you posted….

    But I was thinking of buying a new spring and ball maybe my spring lost tension 

    Fingers crossed..
      
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  • Re: Severe Jittering Oil Pressure

    by » 7 years ago

    Hi Roger,
    Thanks for responding. Please look back to my original post which started this thread. I have used the new style screw plugs at each replacement. I have tried twice to use the mushroom instead of the ball. In either case, I have replaced all parts, including the spring each time I took things apart. The result is always the same. The problem goes away for somewhere between 25 and 50 hours after parts replacement, then returns. While it's possible something else is going on, I don't understand why replacing the valve parts cures the issue temporarily. I have checked everything I can think of (hoses, hose routing, tank, etc) to no avail.
    Alex
      
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  • Re: Severe Jittering Oil Pressure

    by » 7 years ago

    Rob any comments or insight.

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

      
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  • Re: Severe Jittering Oil Pressure

    by » 7 years ago

    very strange, normally the fluctuations get better over time.
    Check the valve seat inside the pump for damage or contamination.
    Are you positive a hose is not collapsing as it gets hot? is the hose vacuum rated?
      
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  • Re: Severe Jittering Oil Pressure

    by » 7 years ago

    Hi Rob,

    Yes, it is very strange. My hoses are high quality, as supplied by Van's in the RV-12 kit. I believe they are vacuum rated. Besides, if it was a hose collapsing, changing the ball, spring and screw plug would not fix it for 25 to 50 hours. I looked at the ball seat in the oil pump. I do not see any irregularities, but I have no means to determine if the seat was machined correctly.

    This issue has been going on since the engine had only about 25 hours on it. Obviously, I am totally uncomfortable with this situation and I'm losing confidence in my engine. I would like to replace the oil pump as the next step. Would Rotax stand behind that under a warrantee claim?

    Thanks,
    Alex
      
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