Gas Burp while filling

Discussion in 'Boats, Motors, Trailers and Towing Rigs Forum' started by RogersonCrusoe, May 6, 2019.

  1. mbowers

    mbowers Active Member

    I have not tested my theory yet by swapping to an angled fill from the vertical one I have that sprays a lot of fuel but I'm pretty sure a vertical fill will not trigger the auto shut off early enough.

    The sensor tube triggers the shut off with a certain amount of pressure from fuel (head / cm of fuel) . If the nozzle is vertical that might be 5cm from top of the fill. If the nozzle is angled at 45deg the auto shut off should trigger when fuel is 7cm from top..

    Anybody see any holes in my theory?

    I've never seen a vertical fill on a road vehicle but sure see lots on boats.
  2. ab1752

    ab1752 Well-Known Member

    There is a vertical fill in my old 911 It will burp fuel too so I have to insert the nozzle effectively backwards so the grip is pulled towards me. if I don't it shuts off every few seconds. I'm going to try this method when I fill the boat tomorrow.
  3. Chuck

    Chuck Active Member

    My Weldcraft pukes fuel also, very poor vent system. Now what I do is stop the fuel flow pull the nozzle out every few minutes and let air into the tank to breath then continue. Pulls air in hard if I wait too long to vent tank while filling. Does similar thing if boat sitting on the trailer on uneven ground in the sun. In that case I just twist off the fill cap a bit, then all can breath. Vent must be in a bad position. Good luck..
  4. Geno

    Geno Member

    I'm getting a lot better listening for the gurgle while filling to prevent the back spash. I might give this a try: www.
  5. Rockfish

    Rockfish Well-Known Member

    If you want to avoid fuel spray and other problems be careful when you replace your worn out built in metal fuel tank. I did a lot of reading and research before we had our keel line Al. custom built tank made to replace the warn out factory tank. From what I learned the tank needs to be built to industry and government standards and be designed specifically to work with your boat/hull and your boats fuel supply and vent system. Those systems and their locations need to be designed to all work optimally together. We could not find an out of the box tank that would match our boat.

    There are likely many with the welding and fabrication skills to build you a replacement built in tank, but not all of them may have the marine experience or design knowledge necessary. We had ours built by a small marine shipyard with experience building marine metal fuel tanks to Canadian Govt. Standards. They also for the most part cloned the boat manufactures original tank which was built to US Govt. Standards and also was correctly matched to the most effective vent location for the tank and its location on the keel line and the design of the boat and hull.

    What I learned is that you don't just weld up a metal box. The tank may have internal baffles but the baffles must allow for the sufficient flow of air/fuel, especially along the length of the inside top of the tank so as to not trap or restrict air rather than vent it . Our original factory tank was designed with the fuel filler and outlet tubes at the stern end of the tank and the vent out to the hull very far forward towards the bow end of the long but not very deep keel tank. A good tank design, location, mounting and fuel supply and vent systems must all work together optimally taking into consideration the design of your boat overall. In short, the factory marine architects/engineers likely got it right and you don't want to make it worse when you replace the tank.
    Last edited: May 21, 2019

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