New Kart, need help

[CraZyQuick]

So my new 150 trailmaster came today. It's all together but I'm a bit confused with the fuel lines. I took some pictures so you can see and maybe help me out. When the kart came there was a fuel line with the spring hanging from the carb, and another from the tank. If I'm correct the line with spring goes to the top outlet on the bottom on tank ? and the line on the bottom outlet goes to the Y, but there were 3 lines into the Y already so I have a line thats not plugged into anything. Please help ..

 

[noiseguy]

Appears you have as vacuum operated petcock. Lines from tank, big one flows fuel little one needs to see engine vacuum in order to flow fuel.