The actuator plumbing is looking for trouble, there's nothing wrong with the std amal valve.
The addition of hunting tells me it is the CO, it is running very lean by the sounds of it, richen it up to around 2.5 % CO, obviously this needs doing on a gas anylyser, but if it is a car that you don't know the true history of I would suggest that first you replace the coolant temp sensor, this is at the rear of the head on nearside(inlet), a blue sensor with a two pin plug on it, this ensures the fuel mix is correct at the correct temp and is the main corrective factor for fuel mixture.
Just a simple turn of a screw afterwards on the ecu will have it nice and happy!!
tabetha