Very Fast Idle Cold

[parkersnine]

Just got the 3gee started upon rebuild. Engine revs to about 4k then we shut it down.. I am hoping someone can give me a good starting point...The carb is not original and do not know if the rpms would continue to rise or not. Thanks!

[A20A1]

The TC (throttle controller) screw should temporarily be turned all the way out negating any effect it could have on raising the idle speed, because the TC can raise idle uncontrollably if there is a vacuum leak. The TC needs proper adjustment and steady vacuum for it to resist the internal spring pressure that presses against the throttle linkage and raises the idle.

[A20A1]

The TC Vacuum Diaphragm is on the throttle cable side of the carb at the front. The TC adjustment screw is accessed from the front of the carb.
Idle speed should be set using the black throttle stop screw knob at the back of the carb. Set it as low as you can run steady for now.

[parkersnine]

Will try the idle adjustment thanks . Would a malfuntioning choke pull off cause fast idle cold or only messed up idle when warmed up?

[A20A1]

Also check fast idle setting... the fast idle screw is pretty low on the carb and hiding between the black throttle stop screw and the TC screw.


Not sure, it's been a while since I ran anything with a choke, but if the malfunction is from a vacuum leak then there you go.

[parkersnine]

Well..Adjusted the throttle stop screw and the fast idle screw and it had no impact on the fast idle cold. When I replaced the original carb with a supposidly lower miles one I purchased I did sysytematically replace the original cracked vacuum lines with new lines. If someone has any more suggestions please let me know. In the brief moments the rebuilt engine has been running it runs good. Because the idle quickly races to about 4k we do not continue to let it run .