Crossflow Idling at too high revs

[Eric Mc]

I seem to be having a problem with my Crossflow 7. Once the engine gets warm, the revs won't drop back to normal idling speed. It's settling at about 2,000 rpm which is too high

I've tried playing with the idle screw on the throttle linkage but it doesn't seem to make a lot of difference. Any ideas what the solution might be?