Paul,
        with a slide throttle in the closed position, Approx. what gap should
there be for the engine to idle?  My preliminary adjustment has the throttle
fully closed!  That would be interesting on final!   Neil.

Perhaps you have some leaking going on.
What idle RPM are you seeing? Is the engine running?
Is there a prop load on it?

If the gear box is on and there is a prop on it it must
idle 1800 engine RPM or more. The prop RPM will then be 630 RPM with
a 2.85:1 gear box. About 200 RPM slower than my O-470 can manage.
If you try to idle the engine slower than that the gear box will rattle.

Paul Lamar