Ok cool. So it is not a tuning issue then. Tuning these carbs adjusts the mixtures, It will not affect the stopping nor the full speed revs. The revs are governed by the Governor and its spring. Being that you have changed the carburettor, it is always a good idea to adjust the governor. Simple process, you will probably have to remove the throttle control at the back of the motor where the throttle cable goes. loosen the nut on the governor arm and hold the throttle wide open. while holding that twist the shaft the same way until it stops and tighten the nut.
If it still over revs and the spring doesn't look modified or shortened, try bending the bracket it attaches to, some people fiddle with these to try and get more power from the motor. They do, but the engine also goes bang.
As norm said stop switch wire will go from under the cowl to the throttle control at the back of the motor. usually to an insulated bolt. there is then usually a wire from there to the key switch. check something hasn't fallen off or been cut somewhere.
I just found you're pictures!. so the brass coloured screw on top should be wound all the way in. I do not know why these have a spring on the aftermarket carbs. Also by the way there isn't a kill wire attached to the motor that i can see. check for a loose wire lying around.
