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Discussion Starter · #1 ·
I seem to be having a problem with my holley 4160 vacuum secondary carb as it doesn't appear to be opening up the secondaries. When I look down into the carb the primarys are all clean from having fuel in them but the secondaries are dirty like they have been dry for a while. The only way that I can get the butteryfly on the secondaries to open by hand is to manually pull the throttle back and then push the lever under diapragm housing. Then they open only about a 1/4 of what the primaries open and no fuel squirts out like on the primaries. I checked the spring and the previous owner had the yellow tipped spring in. The car runs anemic and I am not sure what to do as I haven't really done much work on a carb before. The carb is at least 15 years old and the previous owner has told me that it was rebuilt at least twice. Thanks
 

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I recently rebuilt my Holley 4160. It was fairly simple, but my secondary butterflys were also 'frozen' stuck. Once I got the base plate off, I hosed it down with WD-40, and worked it with my hands for a little while. It eventually became unstuck and worked just fine. I'm sure you don't want to have to take it apart, but I wouldn't spray WD-40 on it while it's still all together. It seems like things like this just need a good cleaning. Good luck.
 

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OK, it's a vacuum secondary carb. This means that the secondaries will not open unless the engine needs the addition air flow. Between your engine combo and driving style, you may not be reaching the needs for the secondaries to open!

Also you did not say what size your motor is, state of tune and carb size, this will have a big effect.

But you could have something wrong though. You could have a secondary spring that is too stiff, a block vacuum passage, torn diaphram, ect.. Also you will not see gas being squirted when you open the secondaries. That is because vacuum secodary carbs do not have accelerator pumps like the primary does. Only a mechanical secondary carb will have an accelerator pump like the primary side.

A trick to see if the secondaries are opening is to put a paper clip on the secondary linkage. Then take the car out on the road and get on it hard. Come back and see if the clip moved. At least you have a starting point. With the carb that old, there's no telling what's been done to it as well. Also your engine being sluggish may have to do with your engine and not the carb. Even if the secondaries are held shut, it still should run well and not be sluggish, just not as quick.

Give us more info and get back.
 

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Discussion Starter · #4 ·
Thanks for the response.
The engine is a 289 in a 65 fastback with 600 cfm holley vacuum secondary, melling cam, edelbrock perform intake, 4 speed toploader and 3.89 gears. The car dosn't run sluggish it just doesn't seem to have much preformance. I have tried the clip and the secondaries are not moving, I don't know if they are stuck or something is not hooked up rigth. Should I check the fuel bowls as it seems to me that it doesn't seem to be getting fuel. I have checked the diaphragm and the spring is the yellow one which is supposed to make them open the fastest from what I understand.
 

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Suck on diaphragm port (with pod removed) and note whether diaphragm holds vacuum or not. Holley diaphragms can be tempermental.

Re-check freedom of linkage/throttle plate movement while pod is off.

You have plenty of engine and gear to get deep into the secondaries. By all rights, you should have a low 14 second, high 13 second combo if it's built right.

As was noted, vac-sec carbs don't have accelerator pumps on the secondaries. Even with the secondaries inoperative, you should still have a very spirited ride. My car only lost about a half second (from 11.50 to 12.00) when shutting off the secondaries. Still very impressive for a 2 barrel *G*

Get back to us...
 
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