Idle problem

[fstblk66]

Idle is currently set at 750 RPM, which is fine until I exceed 3000 RPM for a few seconds, at which time idle begins dipping below 500 RPM (while at a complete stop in neutral) eventually shutting down. Tried adjusting idle screw to 1000 RPM and again once car exceeds 3000 RPM idle reduces (in this scenario) to 750 RPM. Carbureator was recently rebuilt, is there anyone that has experienced this annoying problem ?. (66 427/425)

 

[motorman]

Idle is currently set at 750 RPM, which is fine until I exceed 3000 RPM for a few seconds, at which time idle begins dipping below 500 RPM (while at a complete stop in neutral) eventually shutting down. Tried adjusting idle screw to 1000 RPM and again once car exceeds 3000 RPM idle reduces (in this scenario) to 750 RPM. Carbureator was recently rebuilt, is there anyone that has experienced this annoying problem ?. (66 427/425)

check the opening of the primary idle transfer slots and if over .020 try close the primary side to this spec and then opening the secondary some to get the correct idle speed