fuel tank overflows

[j0hn]

When I fill my tank gas flows out of the fill input when it is full. I usually fill it as slowly as possible. The vent is located below the fill hole, but fuel does not usually flow out of there. The lines are not kinked or bent. The fill line makes a gradual slope to the tank and the vent line is located next to it on the tank. I don't think it is obstructed. If I remove the cap and blow into the vent, air comes out of the fill hole. If I blow into the fill hole a little air comes out of the vent, but it builds up pressure and most comes out the fill hole. Any ideas?

 

[mattttt25]

Re: fuel tank overflows

john,<br /><br />is this a large tank? do you usually fill from the pump or pour from separate container?

 

[j0hn]

Re: fuel tank overflows

Matt,<br />This is a 21 gallon tank. I always fill from the pump and set it on the first notch. It usually turns the pump off, but a lot of fuel still spills over.

 

[Mikedg]

Re: fuel tank overflows

Check your vent fitting screens for corrosion or wax build up. If this is not the case remove the vent line from the tank and check for obstructions by clearing with compressed air. I had this problem with my boat due to the screens being clogged. The fuel would kick back through the fill when fueling to quickly or when nearing the capacity of the tank.

 

[mattttt25]

Re: fuel tank overflows

john- agree with mike, sounds like it has to be the vent line. filling slowly may hurt your cause as well, overriding the pump's back pressure auto-off function (like when we top off our car's tank). good luck-

 

[j0hn]

Re: fuel tank overflows

Both the screen and the vent tube are clean and free of any obstructions. It seems that air can get in, but not much out. Could there be an anti-siphon valve or something inside the tank at the vent tube fitting, or maybe the fitting is just too small?

 

[philtheskipper]

Re: fuel tank overflows

I also have the overflow problem, but the gas comes out both the vent and fill tube. No matter how slow I fill it up some gas always spits out when it gets full. This is a concern because I sometimes fill the boat up while in the water and I have to try to hold a towel under each opening so I don't get gas in the water.

 

[denniz]

Re: fuel tank overflows

Hey Phil make sure your tank vent hose is routed much higher than your fill hose. It could be gas getting siphoned into the vent line restricting it from venting properly.