Went to raise the idle the other day and the screw won't turn.
I adjusted the idle about 6 months ago and it was ok.
Tried to turn the plastic knob with pliers but I'm afraid that
it is going to break.
Can't get a good enough grip with needle nose pliers
to turn the metal stem.  Not enough clearance.
Any suggestions?
Hate to take everything apart.

There's a thread locking substance on the idle adjust, but it shouldn't freeze it.

Sounds more like it's cross threaded.

Can you unscrew it and clean the threads?

Might be easier if you pull the carbs, too.

It's not cross threaded.
It's been in there since new.
Used it only a few times since 2002.
Guess I'll have to pull the carbs.