It's on the passenger side of my carburetor. Appears to be leak fuel. Runs like crap. I have to keep my foot on the gas to keep it from dying. Small amounts of black smoke are coming out of exhaust. Fuel filter is half full of air.

 

Does your truck have Air Conditioning?

I believe that part is the A/C idle up actuator. It raises the idle a bit when the A/C is on to prevent the truck from stalling with the extra load of the A/C compressor.

 

It does have AC.

 

I'm looking to buy a new carburetor from National Carburetor. Does anyone know if all carbs will come with the "Idle-up actuator" for air conditioning???