holley 650 secondaries not opening

[Scott42316]

The secondaries on my 65 aren't opening. Are these supposed to be vacuum or mechanically operated ? The carb has an electronic choke.

[Clem Z.]

Re: holley 650 secondaries not opening

i have seen the little ball check valve in the secondary diaphram chamber get all gummed up and not allow the vacuum to open the secondary. what is the "LIST" number on the front of the choke housing.

[Jim T.]

Re: holley 650 secondaries not opening

I have a Holley 650 spreadbore on my 68 that has mechanical secondaries. A few years ago my mechanical operated secondaries would not open. It had been awhile since I had driven the car. I sprayed some penetrant on top of the butterflys and gently unstuck the butterflys without bending or breaking anything. I now make it a habit of driving it with enough throttle application that the secondaries are used more often.

[Scott42316]

Re: holley 650 secondaries not opening

Hi Clem,

Thx for the response. I still have to check the LIST #, but I did take a closer look last night. The carb is pretty new, but I suppose anything can happen. The butterflies are free. I'm not really sure if this is a mechanical or vacuum operated secondary arrangement. My guess is it's mechanical since there is linkage on the left side of the carb that is connected to the primaries. However, the linkage almost looks like it's installed incorrectly. That is, as I open the primaries, the linkage is connected such that it does not pull the secondaries open. If I were to install the linkage in a different hole on the bracket on the primaries, it appears they would get opended as the primaries get opened.

I need to get the carb #s and check with holley unless one of you guys know.

Thx.

[Scott42316]

Re: holley 650 secondaries not opening

Hi Jim,

Thx for the reply. See my response to Clem. ANy further ideas are appreciated.

[Clem Z.]

Re: holley 650 secondaries not opening

vacuum secondary ones also have a link that is there to help close them when the primary closes. if the link on the secondary side is in a curved slot the carb has a vacuum operated secondary.maybe some one can post a picture of the diaphram side of a vacuum secondary carb to show the diaphram housing which the mechanical one would not have.