Holley Secondaries Sticking

[440sixpack]

 Been driving the new 428 a bit here lately and until now everything has been text book perfect. 

Now that it has about 500 miles on it I decided to run it a little harder and when I got home I couldn't get it to idle under 2k.  so I pulled the air cleaner of and checked everything out and found the secondaries  had stuck open a little . I couldn't push them back without working them open a little more then they fell back in place.   I tried to get them to stick again by hand but so far they haven't.

This is a brand new vacuum secondary 4160  .   any ideas on what caused this and how I can prevent it again? 

[Drew Pojedinec]

Normally it is simply an issue of the throttle plates not being perfectly centered or machined.  Some 400grit and a lil bit of time loosening the plates and finding their happy spot should cure the issue.

Thumperbird just dealt with some of this here:
http://fepower.net/simplemachinesforum/index.php?topic=7559.0;all

[427LX]

Also check and set that secondary end link to just touch the end of slot on secondary shaft.
That will ensure it closes and also keep it from cracking open and raising idle if you use a lighter vac. tension spring.

[67428GT500]

If you missed the thread; I sent Drew my brand new set of reproduction BJ-BK carburetors. Not only were there issues with the throttle plates but several issues with the quality control and even two different size air bleeds on the same block. They were also oversized for the application. No matter what I did they ran rich as hell at idle.
He got them ironed out and tuned them on his vehicle so It should be damn close on my Shelby.
Quality has gone to hell and I can only recommend that you have new carbs blueprinted by Drew. I have never had an issue getting a single quad dialed in. The dual quad was a whole different game and Holley "junk" didn't help my plight.
                                                                                      -Keith

[440sixpack]

Thanks I'll check these things.   I know the end link I guess you call it, was tight because I tried to force the throttle down to the idle position and it wouldn't let me.   

[Falcon67]

IIRC, almost every vacuum 600 carb I've used I had to go and just barely break loos the secondary throttle plate screws, seat the blades and re-tighten.  And maybe buff the edges a bit to help smooth the operation.  X2 - also check the link and make sure it's pulling them down.  The blades are over centered on the shaft, so when nearing closure engine vacuum should pull against the larger blade area and force them down against the stop. 

[Drew Pojedinec]

Be very careful, if the VS link is too tight, it can also make either throttle sticky.
If the plates and shafts are smooth in the baseplate, it should shut without the link assisting.

No need to send these to me (thanks Keith), just about anyone who is willing to take a little bit of time, can get the baseplate squared away.  It can be frustration, but no reason a person can't do it.

[Thumperbird]

Yep, just did my two new slayers due to same issue.
Fit and finish are marginal from the factory, turning it into a fine operation mechanism is not difficult at all as the basic mechanics are there.

By the way, when I pulled the primary throttle shafts on the slayers they did not have the thin teflon bushings on the shaft like the secondaries do, same for both carbs., is that normal?  Might want to check yours.  I have reached out to Holley but no response yet.

[Drew Pojedinec]

Primary shafts don't have teflon ribbons.
Some factory carbs don't have them on the secondaries either.