can someone tell me what part of the carb this is?(picture)

[Renato250r]

I have a trx250r with a kehein 38mm carb, the bike was sitting with fuel in it for the last few months in storage ( I know I know)when I turn the gas lever to reserve or on the hose pictured below starts to drip fuel.... I had the bike running for a min but then it would just start revving real high without me touching the throttle so I just shut it with the kill switch before it got too high. When I start it in the past with the choke up it revs a lil high but this time was diff, was like it was getting gas on its own, throttle is fine..
why would that tube be leaking when the petcock is turned on?
thanks

[DnB_racing]

your float valve is either dirty or sludged and sticking, or the rubber tip is rotted, but you have to take apart the float bowl and check and clean

[CanuckR]

Its the vent tube that connects to the overflow tube in the bowl.
Do what DnB said. Float valve and jets are probably all gummed up.

[pilotpete]

before you strip it ...switch off the fuel ..tap the bowl with the handle of a screw driver (just lightly) switch the fuel back on still tapping the bowl....this will dislodge the float.....works 9 times out 10....