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  • Re: Rotax 912 cylinder running hot

    by » 11 years ago


    Roger and Bill
    I have some new information about the hot cylinder. I switched the probe and got the same results so I don't think the probes are bad.

    On my latest flight both CHT's (left and Right) acted the same. 210-220F during 10 minute taxi at 2000 RPM. ~230F during runup at 3500. Both rose to ~300F during climb at 5400 RPM. ~240-250 at 5000 RPM cruise. And down to 230-240 for downwind at 4000 RPM. Back to ~220F for taxi.

    Suggestions?
    Tony

  • Re: Rotax 912 cylinder running hot

    by » 11 years ago


    I would start by using 50/50 coolant and toss the Evans and then try again.

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


  • Re: Rotax 912 cylinder running hot

    by » 11 years ago


    Can I just drain the Evans and replace it with 50/50 or do I need to somehow flush the system after the Evans is removed?
    Tony

  • Re: Rotax 912 cylinder running hot

    by » 11 years ago


    Just drain it. You can even blow it out since its an open system. You can open the low point and actually blow down through the coolant tank on top. For the most part it will all come out.

    What is your wide open throttle (WOT) rpm in flat and level flight? Is it around 5500-5700 rpm? If you are down between 5100 - 5400 that is also where some of your extra heat is coming from. You're over propped.

    If you are over propped and using Evans then you are adding a lot of heat. Could be any where from 50-75 F and that could take care of your problem.

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


  • Re: Rotax 912 cylinder running hot

    by » 11 years ago


    Yep, just drain it. While putting it in requires draining, prepping, and other hoops to jump through, removing it does not. It is mainly just propylene glycol and what little you don't drain will mix readily with the water and ethylene glycol antifreeze you put in.

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