What hose is this in carburetor? Overflow?

[jyrki]

Hi, as I was making yearly maintenance I note one hose coming out from side of each carburator. Two of those hoses are closed/blocked with a screw, two of those hoses are open. I do not  now mean those two general overflow hoses, these what I mean are four more hoses (one for each carburator). Should all of those hoses be blocked? Has there maybe been some kind of fuel overflow/floating problem with previous owner, so he/she has blocked those two hoses? Is there a risk that those open hoses are taking (suction) air inside to cylinder and causing overheating of cylinder with excess air, so should those be blocked?
br Jyrki

[Pat Conlon]

Choke vent. It draws air into the choke circuit.
A dribble of gas can come out of this hose from leaking float needle seat o rings or dirty float needle.
The real gusher of gas comes out of your bowl vent hoses, typically from a stuck float.