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  • Re: New fuel pump

    by » 11 years ago


    Ken,

    In the rotax fuel manifold, the restrictor screws into the manifold hose nipple. If you make your own, I would use a straight barb hose connector and make a restrictor that would press fit into that. That would allow you to remove it for cleaning if necessary. All you would need is a short piece of brass rod that would press into the brass barb. maybe 1/8"-1/4" long with a .35mm hole drilled through it. The bing jet would also work. It could be placed anywhere in the return line.

    The way yours is plumbed, with the Facet on, the return line is pressurized and the engine runs OK. With the Facet turned off the gascolator is no longer pressurized and, with no restrictor, all the mechanical pump fuel pressure is dumping right back into the gascolator with very little pressure at the carbs.

    Go to the top of this page and click on support. Under that, you can click on the manuals tab and download the 912 installation manual. In the fuel system section you will see the fuel plumbing schematic and also a cutaway view of the restrictor. This can give you some good restrictor installation ideas.

    Bill.

  • Re: New fuel pump

    by » 11 years ago


    OK thanks, the diagram I was looking at was in the Operators Manual which shows a 5 way manifold, but says nothing about a restrictor, but now when I look at the diagram very closely the return nipple looks different than the other 4 (like they are showing a restrictor but its not mentioned on the page 9-2)

    So other than vapour lock the return line helps prevent overpressure of the fuel pump diaphragms correct ?

  • Re: New fuel pump

    by » 11 years ago


    Yes. Although not designed for that purpose, it does slightly reduce fuel pressure. It also eliminates all residual fuel pressure after shutdown.

    Bill.

    Thank you said by: Ken kitzmann

  • Re: New fuel pump

    by » 11 years ago


    Thanks again Bill, the online manual has way more detail than the small Operators Manual that came with my engine 2-3 years ago, and the other manual I had from my first 912 was from 2007.

  • Re: New fuel pump

    by » 11 years ago


    Hi Ken,

    The restrictor is talked about in the Installation manual. The newer fuel pumps and cowled engines should have a return line and all fuel lines should be in fire sleeve.

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


    Thank you said by: Ken kitzmann

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