atc 110 carb problems

[yogi]

The carb was working great, usually, even when cold, one pull would start the machine. One day it started wanting to die, as though fuel starved. I could jiggle the throttle and it would keep running. When it would die, it would take a short while/wait before it would start again. I came home and "fiddled" with it for a while. I got to where it would take 20-30 minutes before it would start, but would not idle. I pulled the carb, cleaned it as throughly as I could. The only problem I could see was a dirty fuel filter. I drained and flushed the tank checked all fuel lines, reassembled the carb and installed it. It starts well, but have to use the choke to start it now. However, I cannot get the idle correct. I set the pilot screw to manual specifications and started the engine. When I start the engine, it will idle satisfactorily for a minute or so then rev up to rather high rpm. When I try to adjust the idle, even with minute adjustment, it will rev down dramatically, and sometimes dies. I tried to adjust the pilot screw to adjust the idle, and it seems to do nothing no matter which way I turn it. It runs even when screwed all the way in. What do I need to check next, or what repair do I need to make. It is all completely stock (1985 model) and I can't afford to buy a new carb. Incidently, it runs an goes well when riding with no apparent carb problems. It is only at idle.
Thanks for any suggestons.

[Mr_RPM]

look for airleaks. intake boot seals end up being broken alot 0f the time and such