i have a couple questions regarding my os120 fs (non-pumped) engine
i bought the plane used for a steal of a price - just want to get more familiar with it

1) i have a fuel line that wraps along the top of the firewall, in the middle of the line is a fitting with a screw in cap. what is this for? i can a pic if needed

2) the carb as a flap with a stiff wire leading down to beneath the cowl, nothing is hooked to the stiff wire so in order to move the flap, i would need to manually twist the wire. what is this set-up for? do i need to do anything with it? should the flap on the carb be in any speceific position idling though wide open throttle? again i can get a pic if needed.

thanks for the help