Change a Fuel Drain Valve without emptying tank

Discussion in 'Miscellaneous' started by cgzro, Jan 21, 2018.

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  1. Jan 21, 2018 #1

    cgzro

    cgzro

    cgzro

    Peter Ashwood-Smith P

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    I've watched people change drain valves (like the Curtis) by simply letting the fuel pour out while you quickly insert the new one. This seemed a bit silly to me, not to mention a tiny bid dangerous. In the past I have drained the tank to do this, usually in conjunction with other things. However today I was in the process of checking my fuel vent line and the obvious idea of simply plugging the vent line, putting the fuel cap on and letting suction in the tank stop the fuel from flowing while you change the valve.

    Anyway it worked like a charm. Just put a bit of hose with a hemostat or tie-wrap to seal it over the vent line, put the fuel cap on tight (has to be non vented type), then drain a bit of gas out of the old valve and presto, it stopped after about a 1/8th of a litre. Undo the old valve, put in the new, unplug the vent line and your done.

    No fuss, no muss, and much reduced danger.

    IMG_4799.jpg

    IMG_4800.jpg
     
  2. Jan 21, 2018 #2

    wally

    wally

    wally

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    Good idea. Changed one on my Cessna 150 not too long ago. Out on the ramp, old one out, new one in, not more than a cup or two ($4.00/gal) lost.
    Wally
     
  3. Jan 21, 2018 #3

    cgzro

    cgzro

    cgzro

    Peter Ashwood-Smith P

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    I suspect you could even retap / follow the threads while the valve is out with this trick if necessary.
     
  4. Jan 22, 2018 #4

    will moffitt

    will moffitt

    will moffitt

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    I think you need to give the vacuum line a big suck before you pinch it off to create a vacuum in the tank. :D

    will
     
  5. Jan 22, 2018 #5

    cgzro

    cgzro

    cgzro

    Peter Ashwood-Smith P

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    you first, i prefer to let gravity do the job :)
     
  6. Jan 22, 2018 #6

    dimcuesta

    dimcuesta

    dimcuesta

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    Good idea. Had to remove one at a contest last summer and this technique would have saved me a bit of fuel!
     
  7. Jan 23, 2018 #7

    airplanegeek

    airplanegeek

    airplanegeek

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    kuddos on your idea of plugging the vent. I do these on a regular basis with out the vent plugged, and if i loose more then a cup or two i am having a bad day. i usually just put my finger over the open hole and get the replacement in place and then do a quick swap.
     
  8. Jan 23, 2018 #8

    cgzro

    cgzro

    cgzro

    Peter Ashwood-Smith P

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    You could use the same trick to replace the sight gauge without draining the tank too.
     
  9. Jan 23, 2018 #9

    Steve H

    Steve H

    Steve H

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    Man, you lose the "air conditioning" effect of the 100LL evaporating as it flows down your arms into your armpits on a hot summer day!

    This is a good idea, thanks.

    Steve H
     
    Larry Lyons likes this.

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