This car belongs to a client who hired me to bring it out of 4 years improperly stored in a chicken barn. Got the car out of the barn this past weekend. He plans on flying to Ontario from Alberta and driving the car back when I'm done addressing everything that's wrong with it, and put insurance on it so I can drive it and find any issues before the trip.

Work done so far on the engine is new plugs/wires/cap and rotor, drain fuel tank of stale fuel, adjust valves and an oil change. Have new fuel and air filters on the way.

After sorting out the braking issues, we took it out on a 200km round trip. The car ran flawlessly, silky smooth power delivery, smooth idle, great acceleration. This morning I got in it and set off on my 5 km drive to work, and at the first stoplight it started bucking and surging and just running terrible at a stop. Would run awful, clear up for a second, run a bit worse, run awful again, run a bit better, etc. acceleration does not seem to be affected.

Had it in the shop tonight to turn the brake rotors and decided to look down the carb. At idle, one barrel is getting a constant supply of fuel, while the other is getting none at all. I don't know which one is normal, but judging by the smell of the exhaust I'd say it's overfueling. I'm guessing a chunk of crud in the fuel system has come loose and is now in the carb, but I have zero experience with this particular carb or multi- barrel carbs in general. Below is a video looking down the carb at idle, you can see the difference in fuel delivery. Any input on the issue would be greatly appreciated!

https://vimeo.com/105088546