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Thread: Riddle Me This... Fuel Valve Leak

  1. #1

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    Riddle Me This... Fuel Valve Leak

    Abridged version - flying along, burning more from left tank. Switch to right instead of both, smell fuel. Reach behind panel, hand comes out with fuel on it. Put the selector back on both, no leak.

    Got to where I was going after a stop to verify it wasn't leaking and pulled the cover. When the right tank is selected, it leaks around the bottom fitting coming out of the valve that goes to the engine. How can it not leak around that fitting when both is selected but leak when the right tank is selected??

  2. #2

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    Upload a picture of the selector and leak. Which selector? Could be a worn a torn o ring, just guessing, show us what you got, the ones I have had apart are SIMPLE, not many places they can leak.. so could be a fitting leaking
    Likes DENNY, flylowslow liked this post

  3. #3

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    From the description, I would say it is a valve position dependent leak that only appears to be at the bottom fitting because gravity is drawing the fuel there. Expose the valve as much as possible, dry it off, use strips of colored paper and press them to all the other fittings and seams of the valve. Test with valve in all positions. Any leak should show quickly on the colored paper.
    DENNY
    Likes stid2677, flywhatever liked this post

  4. #4

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    See if this works…


    Last edited by TxAgfisher; 02-16-2022 at 09:05 AM. Reason: Fixed video link

  5. #5

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    Are you sure thats not OFF at the top? I have a valve like that and its a Left Right Off Off valve, its made by Allen. Why dont you go all the way 360 with it stopping in each position long enough to show when it starts and stops leaking
    Last edited by supercub1999; 02-15-2022 at 10:09 PM.

  6. #6

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    If it only leaks in one ON position that is strange. It cannot be coming out the fitting if its not leaking in the other ON positions.

    The valve is simple to rebuild, there are pics of the valve on here and posts describing how to not lose the BBs that lock the positions
    Last edited by supercub1999; 02-15-2022 at 10:12 PM.

  7. #7

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    Feel the back of the valve. Should be a indent with snap ring in the back. take that piece of paper I talked about and put it over that indent, hold it in place with your finger. repeat test and see if paper is wet. DENNY

  8. #8

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    The only thing that makes any sense to me is what Denny said, check that its not leaking out the back.

  9. #9

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    What would leaking out the back signify and why would it only leak when the right tank is selected?

  10. #10

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    Quote Originally Posted by TxAgfisher View Post
    What would leaking out the back signify and why would it only leak when the right tank is selected?
    A big oring back there that might be getting fubar as you twist to R tank, thats why I wanted to see a video of you turning it all the way around a few times

    You will need one MS29513-011 and two MS29513-114 Orings

    Last edited by supercub1999; 02-16-2022 at 09:58 AM.

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