[steveK]

Why is it that the throttle linkage will not let the carb go to idle on 4 barrel 400 motor? There is about a 3/16 gap in the carb throttle linkage arm to idle screw so I am idleing very high. These are all stock items from pedal to the cable bracket and manifold. I had the same problem on my 69 convertible but I modified the holes on the linkage bracket. There are no adjustments that I can see to rectify this situation. If you "modify" the throttle cable bracket to let the car idle down, you may not get full throttle . Any ideas on this? Thanks in advance.

[steveK]

Why is it that the throttle linkage will not let the carb go to idle on 4 barrel 400 motor? There is about a 3/16 gap in the carb throttle linkage arm to idle screw so I am idleing very high. These are all stock items from pedal to the cable bracket and manifold. I had the same problem on my 69 convertible but I modified the holes on the linkage bracket. There are no adjustments that I can see to rectify this situation. If you "modify" the throttle cable bracket to let the car idle down, you may not get full throttle . Any ideas on this? Thanks in advance.

[pontiacmark]

A couple of things to check, is the cable a 4 bbl cable (different than 2 bbl)? Is the bracket correct? Someone had placed a '66 and earlier on my '70 GTO and it had the same problem you described.

[Held for Ransom]

It's easy to check the throttle bracket. If it's original, look for F-4 stamped into it.

[steveK]

Yes and yes, the cable is for a 4 barrel and bracket has F4 on it. All equipment is original. The only thing is the carb was totally rebuilt so I dont know if there may be something amiss.

[BVR421]

What do you mean the carb was totally rebuilt? As in, you exchanged the real carb for this one? Also, check the linkage on the choke fast idle make sure it isnt stuck on the highstep. Did this carb EVER work properly?

[RAJ7395]

Disconnect the throttle cable at the carb and see if the carb returns to low idle.

If it doesn't return to low idle then gently rotate the throttle linkage and see if you can get it to go to low idle. If rotating the linkage manually works then replaced the spring with a tighter one. If it doesn't work then rotate the choke linkage on the right side of the carb (the wierd lookin stamped piece just to the rear of the vacuum bell) cloclockwise until the choke plate is wide open and recheck the idle, check the 400 kickdown switch for binding (if equipped), check the secondary butterfly return spring on the left side of the carb base and make sure it's still in place and working.

If disconnecting the cable allows the carb to hit the low idle stop then check to see if the cable is operating smoothly (these things corrode inside and stick which is very dangerous), check to see that your pedal isn't getting hung up on a floor mat, check to see if the throttle pivot isn't binding.

Just my thoughts
Rob

[steveK]

Rob, thanks, the problem was the choke linkage was hung. Rotated to full throttle (not running) and retied and she stepped down on idle and has not hung up since. Thanks guys for the info. I take it one battle at a time you know!!!!