what exactly does the Spout do - what is it for ???

 

SPOUT stands for SPark OUTput. The EEC-IV computer gets information (cylinder ID, PIP TACH signal, etc.) from the ICM. The EEC_IV computer then calculates the desired spark advance from this information and other information (MAP signal, TPS signal, etc). This SPark OUTput advance signal is then sent to the ICM which controls the firing of the spark plugs. If the ICM doesn't get any signal from the SPOUT circuit, then the ICM fires the spark plugs at a fixed "base" timing -- usually 10 BTDC (which is why you unplug the SPOUT connector when setting base timing, to disable the timing advance).