Hi. My ul (equipped with 912S) doens´t have a fuel filter, only an ACS gascolator. I would like to instal a 70 microns filter on the fuel line before gascolator and the fuel  pumps. 

Would like to know the diameter of bing carburator needles.

Please give some opinions on that issue. 


  • Re: Avgas Filter

    by » 5 weeks ago

    Basically any off the shelf inline fuel filter will work.

  • Re: Avgas Filter

    by » 5 weeks ago

    It has been suggested to me that one should not use a "paper" element filter if using mogas with ethanol.

  • Re: Avgas Filter

    by » 5 weeks ago

    Does your aircraft fuel system have an auxiliary electric boost pump? A return line to a fuel tank with a restriction office? I respectfully add to those who make suggestions to you, that you download the free maintenance manuals available on this site, including the Installation manual, where you will find the information about the Rotax-recommended configuration and design of your fuel system, including fuel filter information.

  • Re: Avgas Filter

    by » 5 weeks ago

    Normally a gascolator is a fuel filter....although a coarse one. Therefore the fine filter should be after the gaslocator...


  • Re: Avgas Filter

    by » 5 weeks ago

    The ACS Gascolator is supplied with either a 74 or a 120 micron filter.

    You may have overlooked it.  It is a flat circular disk of extremely fine Stainless Steel screening.

    Replacements are readily available from A/C-Spruce for under $4.

    - - -

    Paper Filters do not like water.

    Paper Filters and 100LL or Ethanol Free MoGas (E-0) would be the worse combination.

    ANY amount of water in 100LL AvGas is going to cause problems.


    E-10 MoGas would be the better combination.

    E-10 MoGas will keep up to 1/2% of water harmlessly in solution.   Harmlessly!!!

    1/2% is ~1/2 ounce per gallon, or over 12 ounces per 20 gallons.

    That is a lot of water to get iinto a tank, and would have you rethinking the entire flight if you ever drained a cup and a half of water out of the sump.

    The Paper Gasoline Filter concern dates from the days when lead was first removed from gasoline and a number of Octane Booster Replacement additives that are NO LONGER legal for use would form mixtures with water that would not pass through paper filters.

    Ethanol does NOT have this problem.



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

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