Err.. I'm surprised no one said anything about the set screw, which is probably the culprit
Also.. less probably, maybe the carb hase a hole somewhere?
Maybe the radio's throttle setting is in "reverse servo" position and its at full throttle during idle?
J/K
The LSN can definitely have a big impact on idling, but if your sure its tuned right and it still idles high, I'd take a good look at the set screw!
Adjust the LSN to have a good low range, not to get a good idle!
ram