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-   -   stuck open secondaries (http://www.clubcobra.com/forums/shop-talk/114186-stuck-open-secondaries.html)

aa909 01-30-2012 05:28 PM
stuck open secondaries
 
Hi Guys

I started the car last night and it fired up fine but had a rough idle around 600 rpm (normal cold idle is 1200), and after 20 seconds the idle picked up and started rumbling fast. Shut it down and waited 30 minutes, fired her back up again and the same thing happened

So this morning I took my air cleaner off today (car was not running) and noticed the secondaries were stuck open half way. Couldn't move the valve, and the arm was stuck as well. Toggled the arm back and forth a few times and freed it. Now it is loose and opens and snaps shut freely when I move the arm.

Haven't started it up yet but I was wondering if you guys can tell me the obvious symptoms of stuck open vacuum secondaries?

thanks
Art

zrayr 01-30-2012 06:08 PM
Runs lean.

Z.

Cashburn 01-30-2012 06:25 PM
Could the linkage be hung up after the air cleaner base was swapped?

lovehamr 01-30-2012 06:40 PM
What carb?

aa909 01-30-2012 06:40 PM
Quote:
Originally Posted by Cashburn (Post 1173380)
Could the linkage be hung up after the air cleaner base was swapped?
Hi Jay

I haven't swapped the base yet, waiting for my BAR appointment in a few weeks before I do that. Not sure what would have caused it to hang up but it's loose now. Sounds like if it runs lean with open secondary then that explains the rougher idle around 600 that I experience yesterday.

aa909 01-30-2012 06:42 PM
Quote:
Originally Posted by lovehamr (Post 1173384)
What carb?
It's a quick fuel 780 cfm hot rod series w/ vacuum secondaries

lovehamr 01-31-2012 02:52 AM
Check the linkage that I have pointed out with the red arrow, when the primary throttle plates are closed it should be snug.

http://i266.photobucket.com/albums/i...vehamr/QFT.jpg

The vacuum secondary diaphragm spring will push the secondary plates closed but there are several tension levels available for those springs and they mostly determine how quickly the secondaries open, not how well they close. This linkage is what's most responsible for making sure that the secondaries close with the primaries. It can be bent one way or the other (I just use pliers or vice-grips) to make sure that they are closed but NOT holding the primaries open either. If this is set right, the secondaries are subject to the same return spring pressures that the primaries are and should solve any problems like that. Hope that helps.

Steve

aa909 01-31-2012 06:32 AM
Thanks Steve. So when I check this linkage am I checking to see if it has been bent?

Silverback51 01-31-2012 03:26 PM
Quote:
Originally Posted by aa909 (Post 1173451)
Thanks Steve. So when I check this linkage am I checking to see if it has been bent?
Correct. It should not be binding or holding the secondaries open.


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