yeah, but sometimes the solenoids dont work, so people just wind the screw in to make them idle.
Sometimes the shafts wear, and they such air in from there, causing them to idle lean and run on,
Possibly a spacer / heat insulator may help also, alternatively it may also be a leaky manifold gasket too.
Also check the oil, if the fuel pump is leaking, it may be running on fuel vapour in the sump, maybe the vacuum advance is connected to the wrong vacuum port? there is a number of posibilities
What is the idle rpm? does it sound like its idling too fast?