husqvarna 142?

Will not idle down can 't get the chain to stop spinning.
have back idle screw out all the way.no change in rpm.
I have also check to see if carb linkage is hanging up.
When my friend gave the saw to me to fix, it would run for a short time an die. I figured the fuel system&rebuild the carb.
this saw has a new carb fuel lines &filter carb adapter carb boot & fuel pulse tube . I have worked on many
saws in the past as well as other equipment .