Al
It sounds like it is running very lean (lack of fuel) at idle, thats why you have to go slow on the throttle. if you open the throttle too fast it leans out and dies from to much air.
When you give the idle circuit more fuel with the adjustment screw, then it is more than likely getting too much fuel on the top end.
Spraying cleaner in the port makes the port clean, but does nothing for the internal parts of the carb.
I`m having all kinds of trouble with my carbs because of the "corny" gas. Are you using and additive? Maybe someone will chime in on the gas cure. months ago some members mentioned getting gas from major brands. They may all have enthanol in the gas now, I`m not up todate on that.
Now they are talking of going to 15% from the now 10%. I hear all the lawn equipment dealers etc are real busy because of this.
My plan is to install shutoff valves in my fuel lines and run carbs dry after a ride, or drain the carbs that have bowl drains.
good luck! keep us posted.
Ron .