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Thread: Gas Drains Question

  1. #1
    Senior Member Steve Y's Avatar
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    Default Gas Drains Question

    Straighten me out here tech guys-

    The most forward gas drain is the sump of the carburetor ?
    The second (nose) drain aft is the "Steve's" Gaskalator?
    The aft fuselage drain is the lowest point in fuel system between tanks (water catch)?

    Thanks in advance-

    Steve
    Last edited by Steve Y; 09-20-2013 at 11:18 AM.

  2. #2
    Senior Member Pete D's Avatar
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    Default Re: Gas Drains Question

    Quote Originally Posted by Steve Y View Post
    Straighten me out here tech guys-

    The most forward gas drain is the sump of the carburetor ?
    The second (nose) drain aft is the "Steve's" Gaskalator?
    The aft fuselage drain is the lowest point in fuel system between tanks (water catch)?

    Thanks in advance-

    Steve
    Sort of.

    The sump of the carburetor does have a drain but would typically only be drained on the 100 hour or annual condition inspection. It is a small bolt in the bottom aft of the carburetor bowl that is safety wired.

    The gaskolator on the firewall collects sediment from and filters all of the fuel going to the carburetor. It also functions as the low point drain for the left fuel tank and the forward line from the right tank.

    On late model CC11 there is a drain a few inches back from the gaskolator that drains a potential low spot in the line between the back outlet of the left tank and the fuel selector. That low spot typically would only be there if the aircraft had larger tires.

    The drain that is aft of the cabin on the right side of the belly is to collect sediment and water coming from the aft line in the right tank.

    Section 5.4.10 of the Aircraft Maintence Manual has diagrams of the fuel system. It can be accessed on the main CubCrafters website under the Owner Support tab.

    Direct link here.
    Pete Dougherty
    R & D Shop Manager
    Cub Crafters Inc

  3. #3
    Senior Member Steve Y's Avatar
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    Default Re: Gas Drains Question

    Thank you for the support Pete....I'm totally straightened out now! And after sitting
    in the plane with a battery charger going for four hours, playing with the GDU 375
    and Dynon.......I now have them set up to turn on the lawn sprinklers, pool pump
    and Air conditioners at my house! Amazing this Carbon Cub!

  4. #4
    Senior Member John Hodges's Avatar
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    Default Re: Gas Drains Question

    Don't forget the blender!

  5. #5
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    Mission Beach, Qld, Australia
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    Default Re: Gas Drains Question

    I have AC no 167 with a single fuselage drain. I am in avery humid area. I have been experiencing rough running which seems to be corrected temporarily by draining a large sample (a coke bottle) from both drains. After a rough running episode, this collects about a dessert spoon of water from the aft drain, less from the forward. When checking with a fuel sample tube I do not see any water ĖI have to run a large sample. I am not sure why the large sample works when the small one doesnít, just that someone told me to try it. I am concerned that Iím not getting all / enough of the water out. Interestingly, the rough running is usually on late final, maybe due to attitude? Has certainly caused me to routinely do glide approaches! Iím interested in comments as to whether I should install more drains and why there are no drains in the lowest point of each tank? Paul.

  6. #6
    Senior Member Pete D's Avatar
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    Default Re: Gas Drains Question

    Rough running on late final and high humidity make me think carburetor ice is building up when the engine is run at low power settings.

    When I suspect the conditions are such that carburetor icing is likely I tend to keep a little more power in, or every once in a while give a little "burp" of power to listen to how the engine responds. Also using carb heat.

    Another thing that can contribute to carburetor icing or make it worse if there is some is running the engine too rich. A little leaning will sometimes help prevent it as well.

    Try putting the tail up on something, just a few feet off the ground when you drain, that will change the angles in all the lines of the fuel system and might make it so you don't have to drain of liter of fuel out.

    Also, it is recommended that the aircraft be stored with full fuel tanks to prevent condensation.
    Pete Dougherty
    R & D Shop Manager
    Cub Crafters Inc

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