Attached is an image of a HIF44 as viewed from the engine side.
A - fuel inlet
B - mixture adjustment screw (not visible, inside the shield sticking out)
C - Fuel bowl vent and overflow. Should have a tube leading away from engine to underside of engine.
D - Crankcase ventilation port. Should be connected to crankcase vents to capture blow-by fumes etc.
E - Vacuum port for distributor vacuum advance.

Note crankcase vent port should be capped if not connected to crankcase vents. Vacuum advance port should be capped if not used or when setting idle with vacuum advance disconnected (vacuum advance is highest at idle or low throttle).
The fuel bowl vent should never be capped. It allows air flow for changes in fuel level. If your fuel float fails or your fuel inlet jet sticks open, raw gas will be pumped right out this port. Notice this port is higher than the carb throat. If over-fuelling occurs, raw gas will also flow up out of the main jet and down into the intake, making an extremely rich condition. leading to flooding and stalling. Little known issue: the carb jet top is below the top level of the fuel tank. This is good when you have run out of fuel and need to re-prime the system. It is bad when you have a full tank and park the car for the winter, not knowing the fuel inlet valve is stuck open. The tank WILL drain into the gearbox until the tank level drops below the level of the main carb jet. 

Thanks Dan

I thought there was a screw adjustment by where the gas comes in.  If that was on my weber instead of my HIF 44 that was 20 years ago. LOL

No, turn it in - clockwise - to richen. The screw pushes on a lever that pulls the jet down.

In the first picture, you can see the bottom of a HIF44 with the cover removed. The white thing in the middle is the end of the jet - it has an elbow for pickup. The shiny thing opposite my thumb is the bottom of the lever, with its loop end around the jet. The lever pivots on the back edge  and the screw and spring are the return device.

In the second photo, you can see two levers - the shiny one and an older one on the right. You can see the oval loop that goes around the jet. On the narrow tip, you can see a thin slot. This is where the tip of the mixture adjustment screw pushes against it. So, when the screw is turned in, it pushes on the tip of the lever and the loop of the lever goes down, pulling the jet down to richen the idle mixture.

Now the tricky bit! The lever is bi-metallic and warps with increaased engine heat. This is a fuel efficiency/anti-pollution giszmo: when the engine and carb are cold, it allows a richer mixture for driveability and then as the engine warms, the mixture leans out for economy.  The hard part when trying to set the idle mixture in your driveway or garage is that the car is not moving and benefitting from air flow around the carb. Thecarb continues to get warmer and warmer, as does the bi-metallic lever... leaning out the mixture. The result is that you end up trying to chase a moving target. I couldn't get it right.

I believe shops use a very large fan to simulate air flow at road speed. One option would be to make tiny adjustments and go for a drive. Another option is to defeat the bi-metallic action by dismantling the lever and modifying it. I chose to make a plain one out if stainless steel. That worked for me.

How do I richen an HIF44??   Turn it counterclock wise??