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Discussion Starter #1
A while back I rebuilt a Holley 4V w/ vacuum secondaries for my fastback. I finally got around to putting it on the car yesterday. It runs pretty well, but there are a couple of issues:

1) When I am at mild throttle and step on it hard, there is a noticeable bog or hesitation before I feel any throttle response. Then it takes off and pulls fine.

2) When I run through the gears pretty hard, it pulls OK at first and then I feel a noticeable boost at higher RPMs and it really takes off. I assume I am feeling the secondaries kick in, but I never felt such a noticeable difference before. It's like there is an extended delay before the secondaries engage.

When I work the throttle by hand, I can see 2 nice jets of fuel squirt into the carb.

Can any of you carb gurus out there give me so guidance as to what my problem(s) might be?

Thanks,
MrFreeze
 

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1) sounds like a lean issue
2)you should not feel any transition when the secondaries open up on a properly set up 4 barrel.

The squirt you see it the accelerator pump indicating it's working. You can try different setting to see if it alleviates the bog.

I'm sure others can give you better information.
 

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Discussion Starter #5
First, thanks to everyone for their responses.

Boss68: I adjusted the float levels I "think" correctly, but I will re-check next chance I get. The power valve is new, but if it seems like a likely culprit I can swap it out. I don't know what "PVCRs" are - please educate me on this. How would I check for a leak at the secondary diaphragm? The vacuum advance is plugged off at the moment. Here are the part numbers off the air horn:

D0PF-9510-U
LIST-4548
2005

Zrayr: it's not a big carb, about 450-500 cfm. I previously had a 600 cfm on the car that didn't bog. But it was too big (sooty exhaust, fouled plugs, etc).

Beechkid: how do you adjust the power valve? Or do you mean swap it out for a different number? I believe it is an 8.5 in there now.

Thanks again,
MrFreeze
 
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