6 gallon portable gas tank

[boatn]

Are 6 gallon metal portable tanks suppose to vent? After mine sit in the heat for a while the gas expands and spills/vents out the fill neck. The fill caps on mine seal tightly and if I open the caps slowly alot of air is expelled but I still get a spill. Am I suppose to leave the caps on loosely? Do the tanks need rebuilding and where do you buy a rebuild kit?

[boats.net]

The Yamaha metal tanks has a vent where fuel hose connects to tank, a small spring loaded valve. If fuel hose is disconnected from tank, tank will not vent.

[boatn]

Thanks for the reply. So how do I stop the fuel from leaking around the black fitting that screws into the red part of the tank? During the heat of the day fuel continuously leaks from around the fitting. When I open the tank cap LOTS of gas vapor (and some gas) escapes. then at night the pressure equalizes and the same process starts aging the next day. Last week I left the boat outside and I'm guessing about a quart of fuel leaked from the tank. Is that tank cap suppose to have a vent? Is the tank supoosed to be complety sealed? I unscrewed the black fitting, used a little permatex gasket sealer around the gasket and tightened everything back up and the pressure was so high that it pushed the permetex out.

[boats.net]

Tempo used to sell a gas cap with vent that will fit that tank but Tempo went out of business and I'm not sure if there are any others available. May have to replace tank with a plastic one.