Holley Carb Question
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Holley Carb Question
I put a new holley spread bore carb on my 350. The instructions call for the idle speed to be set for the primary and secondary at the same time in equal amounts amounts. The picture in the instructions show he secondary adjustment screw and it appears to be on the bottom of the mounting flange, requiring the carb to be removed for adjustment. I don't feel that this correct, nor can I see the adjustment screw from the top.
I have e-mailed Holley with no response.
Can anyone help?
Does anyone have a picture or different instructions?
Thanks for your time,
gm
I have e-mailed Holley with no response.
Can anyone help?
Does anyone have a picture or different instructions?
Thanks for your time,
gm
Burning Brakes
Joined: Jan 2006
Posts: 876
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From: Same as our leaders Out of my mind
Originally Posted by GM73VETTE
I put a new holley spread bore carb on my 350. The instructions call for the idle speed to be set for the primary and secondary at the same time in equal amounts amounts. The picture in the instructions show he secondary adjustment screw and it appears to be on the bottom of the mounting flange, requiring the carb to be removed for adjustment. I don't feel that this correct, nor can I see the adjustment screw from the top.
I have e-mailed Holley with no response.
Can anyone help?
Does anyone have a picture or different instructions?
Thanks for your time,
gm
I have e-mailed Holley with no response.
Can anyone help?
Does anyone have a picture or different instructions?
Thanks for your time,
gm
http://www.holley.com/data/Products/...199R8108-2.pdf
Melting Slicks
Joined: May 2002
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From: Sulphur LA
St. Jude Donor '05-'06,'11,'13-'14,'16,'18,'19,'24, '25
The spread bore Holley's I've seen are vacuum secondary carbs that don't have the four corner idle system, so they don't have the secondary adjusment screw. What is the list number for your carb? I am no expert on carbs by no means. Hopefully Lars will chime in and set us streight.
the four corner idle carbs have an adjustment screw on the secondaries, and it is adjusted from the bottom. There is a replacement arm that you can order that will allow you to make this adjustment from the top without removing the carb. The P/N for that part is 26-137 but this is for a 1000 CFM HP carb. I am not sure that it will work on your modle carb. I found this part number on the holley site in the tech instructions for my modle carb. Lars recently had a write up stating that both the primary and secondary plates need to adjusted the same amount open.
For the life of me I can not understand why Holley would not install the adjustment arm to begin with, rather than me having to remove the carb to adjust it.
Neal
the four corner idle carbs have an adjustment screw on the secondaries, and it is adjusted from the bottom. There is a replacement arm that you can order that will allow you to make this adjustment from the top without removing the carb. The P/N for that part is 26-137 but this is for a 1000 CFM HP carb. I am not sure that it will work on your modle carb. I found this part number on the holley site in the tech instructions for my modle carb. Lars recently had a write up stating that both the primary and secondary plates need to adjusted the same amount open.
For the life of me I can not understand why Holley would not install the adjustment arm to begin with, rather than me having to remove the carb to adjust it.
Neal
Le Mans Master
Joined: Jan 2003
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From: Tuttle OK
Cruise-In VIII Veteran
Originally Posted by GM73VETTE
The picture in the instructions show he secondary adjustment screw and it appears to be on the bottom of the mounting flange, requiring the carb to be removed for adjustment.
for me, i removed the carb 3 times before i got it close enough for my taste - just a touch of the idle trough showing. from there on, i adjusted the idle from the top.
Lars says that a good tuner will keep removing it 'till it's 100%, so i'm just a 1/2 tuner...
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avette4me
Thanks, I thought I was missing something.
Out of the box, the carb performed very well, but need dialed in.
After you got tired of removing the carb, how and what adjustment did you make from the top side?
Thanks,
gm
Thanks, I thought I was missing something.
Out of the box, the carb performed very well, but need dialed in.
After you got tired of removing the carb, how and what adjustment did you make from the top side?
Thanks,
gm
Le Mans Master
Joined: Jan 2003
Posts: 6,575
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From: Tuttle OK
Cruise-In VIII Veteran
Right or wrong, I set the rear butterflies up so that I could just see a very small part of the idle tunnel. The car won’t idle quite right if I close the front butterflies.
From there, I adjust the idle from the top using just the front butterflies.
You have to set the idle mixture just like normal of course…
From there, I adjust the idle from the top using just the front butterflies.
You have to set the idle mixture just like normal of course…
Safety Car
Joined: Aug 2001
Posts: 3,685
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From: Waterford Mi
I had to do the same thing with mine. After that was done I had to tune in the accelerator pump circut. The carb came with a size 40 discharge nozzle, I ended up using a size 21, the smallest size offered. Next I changed the pump cam. They come in a set wth different colors relating to the amount of gas and time it shoots it. I ended up with the black cam. Now it works great but I am sure a tuner could probably make it better.
