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Last year after on my engine was de-carboned, and after just 10 hours it started buring oil. Smoked for 10 minutes after start up and the oil level in the reservoir would go down about 1/2 inch in 2 hours of use. I sent the engine back this past winter to have this problem fixed. I was told that a seal in the crank was bad and I had a new crank installed.
Now I have oil in the pulse line. I thought it might be some oil left in the engine after rebuild so I put on another line. This line got oil into it after the first flight, and the oil level in the reservoir dropped about 1/16 of an inch. I have never seen oil in the pulse line before.
Is this a problem and does it need immediate attention?
Engine runs fine and all temps are at acceptable levels.
  • Re: Oil in pulse line, 582 Blue Head

    by » 11 years ago


    Oil in the pulse line is usually a sign that the carb on the mag side is contributing to a rich mixture.Is the EGT on that cylinder cooler than the PTO side? The other problem can be the oil injection pump lever isn't adjusted correctly or a cable is sticking for it.Remember ,fuel/oil mixture goes into the crankcase first on a 2 stroke.The pulse line gets pressure/vacuum from the crankcase.That's why you will see residue in the pulse line..

  • Re: Oil in pulse line, 582 Blue Head

    by » 11 years ago


    Hi, thanks for your help.
    The EGT temps are on average about 10 degrees apart and yes the PTO sides is usually the higher temp.
    As for the oil injector, it is disconnected. I mix gas and oil. One less thing to go wrong. My engine guy told me that over 50% of the rebuilds he did was due to oil injector problems. That was enough for me to remove that from the equation.
    Should I adjust the slide in the carb on the mag side to bring that temp higher?
    And am I to think that no real damage is happening? I did not think there was but my engine guy is no longer available and I do not anyone else to talk to about these engines.
    Again thanks for the help!

  • Re: Oil in pulse line, 582 Blue Head

    by » 11 years ago


    As long as the oil reservoir level is not dropping, oil in the pulse line is not necessarily a big deal. In fact, the pulse line oil was such a common occurrence that rotax has a small hole drilled in the bottom fitting of the fuel pump (pulse line fitting) to expel this oil. Only time I've seen it cause a problem was when the fuel pump was mounted vertically and the oil couldn't be ejected until the pump was half full of oil on the pulse line side of the pump. The pump should always be mounted horizontally. so the pulse line fitting is on the bottom. That way, even tiny amounts of oil are ejected immediately. If you have an older pump without a hole, you can drill it yourself. Back in the day, we used to drill a tiny hole in the lowest point of the pulse line itself. Worked great; just had to stick a small piece of wire in it occasionally to make sure it was clear.

    Bill

  • Re: Oil in pulse line, 582 Blue Head

    by » 11 years ago


    You are forgetting that oil in the pulse line can also come from a worn inner crank seal.If that is the case, the rv oil will go down.Remember, that oil doesn't get consumed,it circulates from the center of the crankcase and is the "bath" for the rv shaft.The two crank seals keep the oil in the center.That's why I asked what the EGT's were.If the seal is leaking,one EGT (pto)will be alot cooler than the mag side.The fuel pump "weep" hole is spot-on.

    Shayne

  • Re: Oil in pulse line, 582 Blue Head

    by » 11 years ago


    Hi Shayne
    I flew for 2 hours last night.
    The EGT's were again within 10 degrees of each other. Sometimes the PTO side was higher and sometimes the mag side was higher.
    But I just checked the level in the oil reservoir, it was down almost 1/4 of an inch.
    I suspect you may be correct that the seals on the crank are at fault.
    This is very disapointing, as I said in my 1st post, the crank was just replaced because of bad seals.
    This crank has only 12-14 hours on it and the oil reservior has not dropped after every flight,but clearly I have a problem. Its hard to believe that a seal on the new crank is bad but the oil is being consumed some where. As I said earlier, my engine guy cannot be questioned, medical problems (stroke),cannot speak any more. Perhaps he did not do his best work on the new crank install.
    Now what should I do? It seems I need a complete rebuild again, yes?
    Shayne,thanks for your help and insight.
    And thank you Bill for your thoughts also.
    I'm not sure what I should do next.
    Doug

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