How can I tell if my secondaries are opening ? It's a 750 holley with vacuum secondaries, I installed the lightest spring on the diaphragm which should have caused a hesitation. So now I am wondering if the secondaries are working. I can't feel/hear them... I have checked for vacuum leaks, the gauge indicated 17 to 25 depending on rpm ect. Is there some place to connect vacuum to and see if they open manually ?

Thanks for any advice.

My throttle links indicates WOT

It's on a 406 SB / 700R4 trans / vacuum assist brakes.

Two ways to test this... Disconect the diaphram rod from the secondaries and test drive comparing performance against being hooked up. Or you can put something (paper clip or tywrap) on the diaphram rod that will slide (be moved) if the diaphram pulls up the rod and opens the secondaries... Care should be taken using the second second method as you don't want the clip to keep theme from working but you don't want it to slip from vibration...

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...Dennis
www.camaroslimited.com (http://www.camaroslimited.com)

You should NOT feel the secondaries kick in - if you do, it means you are running way too lean before they open. DjD is dead on on how to check, use one of those ty-wrap things as he suggested.

Good advice..I like the more brutal approach...Just thread a screw into the secondary link..about half way or so..and they WILL open..a trim screw fits fine.Just don't mash right away,or it will bog..bigtime.Wait to about 2500 RPM or so..and again,you will feel them and hear them open.

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Chris Corwel,TC Member 785

Exercise caution with the screw trick!! I know someone that did it and when his foot came off the pedalthe first time he stepped on it the primaries closed but the secondaries hung open!! http://www.chevelles.com/forum/eek.gif Can you say "time for a change" http://www.chevelles.com/forum/wink.gif

You should not feel a kick with a vac sec carb or you're actually loosing performance... That seat of the pants feeling and the sound are deciving...