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And the fuel system hits just keep on rolling.  A friend has a KitFox Vixen with a 914UL and the original builder of this EAB aircraft did not experiment with a fuel return line. 

At idle and up to about 2700 rpm both carb float bowls overflow into their vent tubes and dump fuel into the engine compartment.  (No carb drip trays either.)  Yikes, talk about a fire hazard.  

Kitfox does design a header tank vent line into their aircraft but suggests the builder engineer their own fuel return line from the fuel manifold.  And course our good friends at Rotax say return lines are MANDATORY.  

Has anyone out there for either a Kitfox or any other EAB for that matter engineered fuel return lines?  I am looking for two items that are required for installation to a header tank, a check valve and an inline restrictor orifice.  Source and part numbers, please.  

Thank you


Jeffrey Fritts, USAF (ret.)

www.flywwlsa.com

"In aircraft maintenance, good enough is not good enough."

  • Re: 912 UL in an early Kitfox and fuel return lines

    by » 5 months ago


    For a 914 you do not want any restriction in your return line. Quite the opposite, you want as little restriction as possible. Refer to Rotax 914 Installation Manual.


    Thank you said by: Jeffrey Fritts

  • Re: 912 UL in an early Kitfox and fuel return lines

    by » 5 months ago


    Are you intent on just buying premade parts or are you willing to make them yourself?

    For my return line, I added a 3/8 brass "T" in the pressure hose and threaded a Socket head Cap Screw into the Side Port.

    I drilled an 1/8" hole down the middle of the Cap Screw and then refilled the hole with old fashioned 60/40 solder; It machines even nicer than Brass.

    Next, I drill out most of the solder from both ends, leaving about an 1/8" of bulkhead remaining.

    Finally, I very delicately drilled a #80 (0.0135") hole through the solder bulkhead to produce the restricting orifice.

    Many people use a fuel Jet for the orifice, but sometimes I just like to play.

    There was a post on here a few months ago that referenced someone that was selling completed orifice assemblies but mostly this is a do-It-Yourself Item.

    The 914 Installation Manual, Page 90, suggests that a Banjo Bolt with an internal Orifice could be piggybacked on the fuel Fitting.

    There is no mention as to the source of the restricted banjo bolt.  Shopmade DIY ???

    - - -

    What is your reason/intent for the check valve?


    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    Bill.Hertzel@Yahoo.com
    Clicking the "Thank You" is Always Appreciated.


    Thank you said by: Jeffrey Fritts

  • Re: 912 UL in an early Kitfox and fuel return lines

    by » 5 months ago


    Just to avoid confusion, note that the restricted line in the 914 Installation Manual that Bill refers to is for the fuel pressure gauge. The return line is not to be restricted. I got my restricted fitting from the fine Rotax folks in British Columbia (shop made, I think).


    Thank you said by: Jeffrey Fritts

  • Re: 912 UL in an early Kitfox and fuel return lines

    by » 5 months ago


    Ken,

    Thank you for your advice.  I am working on two other 914 engines, also at this time, that have fuel flow problems. 

    This aircraft is a 912UL and the fuel system is slightly different.  

    Jeffrey


    Jeffrey Fritts, USAF (ret.)

    www.flywwlsa.com

    "In aircraft maintenance, good enough is not good enough."


  • Re: 912 UL in an early Kitfox and fuel return lines

    by » 5 months ago


    Gentlemen, 

    I need to apologize I made a mistake in the post.  I said the engine was a 912UL in the header and wrote 914 in the body.  I'm working on several different aircraft at this time and two of them with fuel problems are 914s and this one is a 912UL.  That is my story and I'm sticking with it.  wink

    Sorry about that.  


    Jeffrey Fritts, USAF (ret.)

    www.flywwlsa.com

    "In aircraft maintenance, good enough is not good enough."


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