What's the petcock?.. Snort!..
...
Sorry... It's the thing you're messing with. It lets the gas flow from the tank to the carb..
The knob on it has three settings. Off, On, and Prime..
Prime let's gas flow without engine vacuum.
Hoses... one big one, goes from the left (shifter) side of the carb up to the petcock, near the knob. It's the fuel line
The other comes from the right (rear brake) side of of the carb up to the backside of the petcock (kinda' hard to see) behind the other one. It's the vacuum line
Two smaller hoses at the rear of the carb are vent tubes
They go here,... and they connect to nothing. They should be open to atmosphere...
Like this..
Ignore the writing in this photo, but this is Prime position) Lever pointing to rear...