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Why did fuel came out the vent when filling?-gctid821852

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    Why did fuel came out the vent when filling?-gctid821852

    1987 2450 Cierra

    Gas was near empty. 55 gal tank. Got to about 45 gal and fuel began spilling out the vent.

    What went wrong? Is this typical?

    Thank you,


    Well the good news is that the tank was not as empty as you'd thought! As the vent line is below the filler pipe level, when the tank filled up, rather than push air out through the vent line, it pushed out fuel. This is not uncommon. Next time you are filling up, listen for the telltale sound that your tank is getting near full. A gurgling sound will alert you. Now is the time to stop pumping fuel. The fuel coming from the station fuel tank is cold, it will expand as it warms up to outside air temperature in your fuel tank, and there's no sense in overfilling the tank.
    Bob Hawes.
    Kelowna, B.C.
    1998 Trophy 2052 WA
    4.3 Vortec, A1 G2


      Yep, just as bhawes said, made the same goof on Friday at the 76 station, wasn't paying attention or listening at the filler hose :whistle:
      Edmonds, WA
      "THE FIX" '93 2556
      Carbureted 383 Vortec-Bravo II
      The Rebuild Of My 2556
      My Misc. Projects


        A frequently discussed topic. Another issue is that the vent is at the rear of the tank and most single engine boats sit low at the stern an air pocket forms in the front of the tank as you fill. At a certain point the pressure will "burp" some fuel up the vent line.

        I highly recommend adding a Racor vent fuel capture unit. I used the LG100. It eliminate the fuel burping out the vent.
        Jim McNeely
        New Hope a 2004 Bayliner 305 Sunbridge Express Cruiser
        Twin 5.7s with Bravo2 drives
        Brighton, Michigan USA
        MMSI # 367393410