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Discussion Starter · #1 ·
Ok men and ladies, I have fought with a rich situation on a 600 double pumper for a while, I called holley numerous times and watched and rewatched videos for this. I have a 358 with with a large valve overlap and low vacuum at idle, like 6hg, with that being said , I call holley and was told to do quite a few things, 1 was block off pv and increase primary jets 6-8 sizes, next time was hey drill a whole in the throttle blades, all this and still no idle circuit. So my fix was as follows, I went back to the primary jets I had before I stepped up too, turned the idle screws in, I recovered an idle circuit around 1 turn out from lightly seated. Before I started I took the carb off set the secondary butterflies at .012 thousandths and the primary source at .020 thousandths. I ended up with a .155 thousandths whole in the butterflies on the primary , I also found that my motor was sensitive to the air filter being clean, I had to turn my idle screws in very little to accommodate for the filter and turn my curb idle up a hair, I hope this helps someone any questions just ask I'll help if I can
 

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Sounds as if you went right back to the out of box settings....jets at 68 and 72 ..?
 

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You don't say how your adjusting the lean/rich screws. First thing I do is set timing. Let it get to operating temp. Find a GOOD manifold vacuum port and attach a GOOD vacuum gauge. Set Idle. LEAVE air cleaner on. Start with screws out 2&1/2 turns each side. Adjust both screws the same going out or in ,what your looking for is max vacuum. Once you have max vacuum you should be set. Be CAREFUL not to lean it out to much unless you want to replace pistons. When its all set and ready I would back the screws out about 1/8 turn more just to be safe. anim_25
 

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Discussion Starter · #4 ·
Sounds as if you went right back to the out of box settings....jets at 68 and 72 ..?
very close , pops had them different ,lean, but I found out the pv was open at idle in gear so I blocked it, called holley and they say step up 6-8 sizes in primary...wrong double pumper has enough lol went back to 65 72, blocked pv ,much better and cleaner at idle
 

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Discussion Starter · #5 ·
You don't say how your adjusting the lean/rich screws. First thing I do is set timing. Let it get to operating temp. Find a GOOD manifold vacuum port and attach a GOOD vacuum gauge. Set Idle. LEAVE air cleaner on. Start with screws out 2&1/2 turns each side. Adjust both screws the same going out or in ,what your looking for is max vacuum. Once you have max vacuum you should be set. Be CAREFUL not to lean it out to much unless you want to replace pistons. When its all set and ready I would back the screws out about 1/8 turn more just to be safe. anim_25
I got truck to operating temperature, set idle air screws at 1.5 turns, watched vacuum gauge till highest vacuum was achieved, about 9hg, set idle around 950-1000, realized I forgot air cleaner, installed it, adjusted idles screws again,i had to turn screws in or lean, and reset curb idle, thanks for the info guys
 
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