Your mixture screws are the needles. When you lean mixture, they are just screwed in closer to the seat.
Click on 'related links' (below) and the link will take you to a diagram.(you need to scroll down a bit)
That is the main jet needle valve.
You can find a vacuum hose routing diagram for a Quadra jet four barrel carburetor at most auto-parts stores. Some Ford dealerships will also have the vacuum routing diagram.
80 and 100
The are on the left portion of the carburetor.
I'll give you 4. The Float System, the Fuel Jet, the Venturi Pipe and the throttle valve.
function of jet in carburettor
In your carburetor. You have a main jet and an idle jet.
primary jet size 105 secondary jet size 150
choke, throttle, jet
Type . . . . . . . . . . . . . . . . BST 34 Mikuni Main Jet . . . . . . . . . . . . 155 Pilot Jet . . . . . . . . . . . . . 45 Jet Needle . . . . . . . . . . . J8--4FA01--3 Needle Jet . . . . . . . . . . . P-4 Throttle Valve . . . . . . . . #100 Pilot Screw . . . . . . . . . . 1.5 Turns Out Pilot Air Jet . . . . . . . . . . 160 Valve Seat . . . . . . . . . . . 1.5 Float Height . . . . . . . . . 14.7mm (.58I)􀁲1mm Fuel Octane (R+M/2) . 87 Non-Oxygenated or 89 Oxygenated
the jets are inside the carburetor. They look like brass pipes, they can be unscrewed. The jets have to be clean (the hole has to run all the way through the jet) in order for the engine to run.
To remove a stripped jet from a carburetor, you can use a screw extractor or an easy-out tool designed for this purpose. First, apply penetrating oil to the area and let it sit for a few minutes. If the jet is still stuck, carefully drill a small hole in the center of the jet, then insert the extractor and turn it counterclockwise to remove the jet. If these methods fail, you may need to consider a drill and tap solution or replacing the carburetor.