secondary throttle blade position

[scremn]

I have read a couple of times about carburetors that have the secondaries
adjusted to be slightly open on some applications. Is this to help improve the
idle on some motors with aggressive cams that have low vacuum or does it
help with an idle that may be too rich. A friend of mine and I were shooting
the breeze about this and would like your input.Thanks for your input.

 

[rumblefish360]

It shouldn't be the secondary throttle blades open for that. It should be ethier a couple of very small holes drilled in the primary butterflies or a Demon carbs idle eaze wi=hich is a controled vacuum leak via a screw in the center of the carb. Normally where the air cleaner stud goes is the location of the screw.

One other way is escaping me right now......

 

[C130 Chief]

Holleys have an adjustable secondary throttle stop. It is possible to open the secondaries slightly at idle so the primaries may be closed farther. This is sometimes needed with long duration cams.

 

[waggin]

You hit the nail right on the head, sometimes when the primary idle circuit is too rich and the mixture screws are unresponsive this can be a great remedy...look for the idle transfer slots on the primary side to be covered or the carb will think it's not at idle and run rich,this is true on most carbs.drilling the butterflies to correct this problem is a last resort and I don't recomend doing it till all other adjustments have been corrected. on the demon with the idle ease you still have to adjust the secondary throttle plates before the idle ease system will funtion properly,with the demon carb you need to read the instructions and adjust everything before installing the carb, contrary to popular belief they need all adjustments checked and the instructions followed and then you have one fine carburetor....This Is all my opinion and ya'll can do what you wan't with your carb,after all it is your carb....do as you will :cheers:

Holleys have an adjustable secondary throttle stop. It is possible to open the secondaries slightly at idle so the primaries may be closed farther. This is sometimes needed with long duration cams.

 

[waggin]

if you uncover the idle transfer slots on the primarys to obtain a suitable idle speed it will run rich and the idle mixture screws will be unresponsive, the secondary throttle plates have an adjustment for some reason.......you hit the nail right on the head....why else would they have an adjustment there???? Demon carbs have a very similar design and if you have instructions for a demon with or without the idle ease system you will find them very enlightening concerning the idle transfer slot's and responsivness of the idle mixture screws...the imformation applies to most carburetors...this is all just my opinion and I hope it is helpful to you

I have read a couple of times about carburetors that have the secondaries
adjusted to be slightly open on some applications. Is this to help improve the
idle on some motors with aggressive cams that have low vacuum or does it
help with an idle that may be too rich. A friend of mine and I were shooting
the breeze about this and would like your input.Thanks for your input.