so the line marked "emissions" is the vent for the tank. disregard that, it connects to nothing.
now, onto more interesting items.... colored circles!
all of these are vacuum lines or connections.
yellowcircle: fuel tap. the "clear line" is vacuum, the black is fuel. now if you follow that thru the sheath you'll see it pops out where the
green circle is. that connects to a T fitting in the
red circle. the fuel dips right into the carb inlet, and traveling upward (to 12 o'clock) is the vacuum line to the SAS system. you can just see it's connection at the 7 o'clock position of the yellow circle. the line continues from the red circle to the
blue circle at the manifold.
okay now that we've identified the suspects... check out that vacuum line-- it sucks (pause for groaning laughter). all kidding aside it looks suspect and is more than likely broken at or near the green circle. also, that
and the SAS line are 100% original and well past their sell by date. I'm
guessing the line from the T to the manifold is as well, and it appears it doesn't even have a clamp on it.
this is some sloppy, low rent work. they swapped your manifold and didn't do the vacuum lines and the new fuel line
appears to have a zip tie instead of a clamp.
replace all your vacuum lines. you can choose to eliminate the SAS and just run direct to the manifold port from the fuel tap (yellow to blue without a layover in T-town), and just cap the SAS up where the port is.
while you're doing that, check the fuel line has proper clamps and test the operation of the fuel tap. fresh clamps for all the vacuum lines as well.
I'm betting this is the source of your problems. and if not, that all needed to get done before repairing whatever the underlying issue is.
go forth. do work. report back.
