Idle speed question

["Mark S. Lepore, M.D." <Sirmoog@ix.netcom.com>]

Hello all:
Another question about my 1971 TR6.
Before I bought it, a reputable mechanic performed a tune up, including
plugs, points, condenser, filters, etc.
The engine idles when warm at 1500 RPM.  I know this can't be right. 
When I shut the engine off, it chuggs for a few seconds.
What is the likely remedy to this problem?  Is there an "idle
adjustment" that I could safely mess with?  Besides this, the engine
runs great.  Starts very easily.
Sirmoog