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Hi,

I had an engine out in my Fisher 303 over a year ago. I never did find a cause. I have since replaced my entire fuel system (except the carb) and now my Rotax 277 runs at 7,000 RPM and over 500 degrees CHT. This is way out of spec! I flew it for 30 minutes, but will not fly it again in this condition.

The total time is 103 hours and I've had two engine-outs for no apparent reason and it's lost 50% power twice as well. It has electronic ignition, a bing 54 carb and it's mounted inverted on my plane.

Do you have any idea what could cause this over-speed and over-temp condition?

 Thanks!

  • Re: The 277 on my Fisher 303 runs very fast and hot

    by » 2 weeks ago


    Hi Larry,

    I would start by looking at the basics...

    Tell us about the fuel you are using.

    Can you post spark plug pictures?

    You said 103 hours TTSN?

    Are you the sole operator of this engine since new?

    How many years old is this engine?


  • Re: The 277 on my Fisher 303 runs very fast and hot

    by » 2 weeks ago


    Well... it turns out that both my (Wesberg/WesTach) CHT and Tach are inaccurate, although I don't recall them being this inaccurate a year ago. I installed a TinyTach, which shows the RPMs well within range and a Digitron multimeter, which is a CHT, RPM, Hours meter used in go-kart racing. It shows the same acceptable RPM as well as the CHT, also well within range. 

    I've put about an hour on the plane since adding these meters with no issues.

    In answer to your questions:

    - Fuel is always 91 octane with Pennzoil Marine 2-stroke oil mixed 50:1

    - Spark plug is light brown and dry

    - A little over 107hrs TTSN, after checking my log book

    - I am the sole operator

    - I've been flying this motor since 2014... 

     

    Thanks for your feedback!


    Thank you said by: RotaxOwner Admin

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