Temperature sending unit.

The "temperature sending unit" that you are describing was actually a 3-port ported vacuum switch (PVS).  Yours was *probably* yellow in color, and controlled the EGR valve.  Some models had a red or green PVS, and they switched vacuum advance from ported vacuum to manifold under certain engine conditions.


In your third picture, that round thing that is connected to your carburetor fuel bowl is called a canister purge valve, and it is missing two hoses.  

The skinny top port should have a vacuum hose that connects to the top port of the PCV valve.  If you don't have a two-port PCV valve, see if there is a tee fitting in your PCV valve hose for the hose to connect to.

The larger bottom port should have a vacuum hose that connects to a two-port ported vacuum switch (PVS) and from there to a ported vacuum source on the carburetor.  See if you have a PVS  screwed into the heater hose elbow located on the intake manifold.

The purpose of the canister purge valve is feed the gas vapors that are stored in the charcoal canister generated from the gas tank and the carburetor into the engine for burning.  Much like a PCV valve, this is actually a good thing to have and it doesn't cost you any horsepower to operate.

The way it is now, the gas vapors are trapped inside the charcoal canister, and it can't be purged, or emptied.  The charcoal canister will become saturated and the trapped vapors are probably all going into your carburetor fuel bowl - not good.  Are you experiencing hard hot starts?


(What is that black thing inserted in the hose right at the carburetor fuel bowl?  Is that a vacuum tee?  If so, there is *supposed* to be bowl vent solenoid valve there instead - either electric or vacuum operated.)