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Old 03-28-2011, 06:10 PM   #1
'72_Cheyenne_Super10
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Question Holley Carb Tuning???

Little help here pro's...

Here's the situation: The truck is running a little rich to begin with and I have a hunch that the carb is the problem. Can someone please tell me how to tune it for max performance? Any tips would be appreciated. I don't know the specific size but here are some pics... I think it is a 600 or 650??









Thanks ya'll!
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Old 03-28-2011, 06:23 PM   #2
elf w/capital T
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Re: Holley Carb Tuning???



Uploaded with ImageShack.us

close all the way *clockwise*

turn with flat head two rotations *counter clockwise* and you should be hearing and smelling a bit better, don't forget the other side, there's two of them!

Last edited by elf w/capital T; 03-28-2011 at 06:26 PM. Reason: dumbass
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Old 03-28-2011, 06:24 PM   #3
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Re: Holley Carb Tuning???

Have you checked your float level, if thats not it try setting the idle mixture
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Old 03-28-2011, 06:27 PM   #4
elf w/capital T
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Re: Holley Carb Tuning???

oh yeah make sure your float level n what not, screw out the screw right infront of what i circled, and peek inside
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Old 03-28-2011, 06:49 PM   #5
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Re: Holley Carb Tuning???

Quote:
Originally Posted by elf w/capital T View Post
oh yeah make sure your float level n what not, screw out the screw right infront of what i circled, and peek inside
What should I see or better yet, where should the float be?
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Old 03-28-2011, 06:55 PM   #6
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Re: Holley Carb Tuning???

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Have you checked your float level, if thats not it try setting the idle mixture
Haven't checked... what should I be looking for?
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Old 03-28-2011, 06:55 PM   #7
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Re: Holley Carb Tuning???

with truck running just bumpthe fender with your leg if gas just does come out your ok, you don't want gas just coming out by itself,
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Old 03-28-2011, 07:03 PM   #8
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Re: Holley Carb Tuning???

hit it with a hammer until fuel starts pouring out. then replace it with a quadrajet.
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Old 03-28-2011, 07:26 PM   #9
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Re: Holley Carb Tuning???

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hit it with a hammer until fuel starts pouring out. then replace it with a quadrajet.
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Old 03-28-2011, 07:36 PM   #10
Sicklajoie
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Re: Holley Carb Tuning???

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hit it with a hammer until fuel starts pouring out. then replace it with a quadrajet.

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Old 03-28-2011, 07:39 PM   #11
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Re: Holley Carb Tuning???

dont forget to check both floats on the carb, also when setting idle mixture if you have a vacuum gauge adjust both idle mixture screws until you reach the highest possible vacuum with your particuler engine
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Old 03-28-2011, 07:44 PM   #12
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Re: Holley Carb Tuning???

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Originally Posted by Pondscum View Post
dont forget to check both floats on the carb, also when setting idle mixture if you have a vacuum gauge adjust both idle mixture screws until you reach the highest possible vacuum with your particuler engine
I just did the two rotations and it seems to crank and idle fine. I'll know if its acting funny when I drive tomorrow. Unfortunately, I don't have a vacuum gauge yet. What am I looking for with the floats?
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Old 03-28-2011, 09:00 PM   #13
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Re: Holley Carb Tuning???

With the truck running at idle you want the fuel just at the bottom of the hole. As FLDAWG stated you want to be able to bump your fender and have fuel come of the sight hole. If your not used to adjusting the floats you'll probably be better off shutting the engine off while your doing the adjustment. Also I believe the Holley web site has a really good how-to on this procedure.
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Old 03-28-2011, 09:12 PM   #14
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Re: Holley Carb Tuning???

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Originally Posted by Pondscum View Post
With the truck running at idle you want the fuel just at the bottom of the hole. As FLDAWG stated you want to be able to bump your fender and have fuel come of the sight hole. If your not used to adjusting the floats you'll probably be better off shutting the engine off while your doing the adjustment. Also I believe the Holley web site has a really good how-to on this procedure.
Thank you... I'll try that and check out the website.
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Old 03-28-2011, 09:17 PM   #15
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Re: Holley Carb Tuning???

If you pull the sight plugs & have fuel pouring out, you found your problem. I had a new 1850 holley on my 401 wagoneer, set it up & it ran great....3 monthts down the road, the bioch is running FAT. Readjust the front float, & 2 months down the road same issue....time to pull the front bowl! Holley dropped the ball for a few yrs & put a lite weight plastic float in some of the carbs(mine was 1). After replacing with a brass float, & adjusting my troubles were done. crazyL
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Old 03-28-2011, 09:27 PM   #16
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Re: Holley Carb Tuning???

Well for all the VERY important info that was missed go get this book http://www.summitracing.com/parts/HPB-HP473/
#1 Float level #2 U use the vac gauge or ear to tune to best vac or Idle THEN You turn each screw in all the way and count the turns you then divide that number in half and screw the mixture screws out that number so they are equal . #3 If your POWER valves are blown U will NEVER get it to run right at idle. I can rattle on for days about it but the book will learn ya right =) then after all that u take and toss it out and get u a TBI setup from a mid to late 80's and never look back (its Cheap)
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Old 03-28-2011, 09:34 PM   #17
'72_Cheyenne_Super10
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Re: Holley Carb Tuning???

Quote:
Originally Posted by crazy longhorn View Post
If you pull the sight plugs & have fuel pouring out, you found your problem. I had a new 1850 holley on my 401 wagoneer, set it up & it ran great....3 monthts down the road, the bioch is running FAT. Readjust the front float, & 2 months down the road same issue....time to pull the front bowl! Holley dropped the ball for a few yrs & put a lite weight plastic float in some of the carbs(mine was 1). After replacing with a brass float, & adjusting my troubles were done. crazyL
If I remember correctly, mine is plastic as well. I'll check that. Thanks for the info!

Quote:
Originally Posted by Madspeed View Post
Well for all the VERY important info that was missed go get this book http://www.summitracing.com/parts/HPB-HP473/
#1 Float level #2 U use the vac gauge or ear to tune to best vac or Idle THEN You turn each screw in all the way and count the turns you then divide that number in half and screw the mixture screws out that number so they are equal . #3 If your POWER valves are blown U will NEVER get it to run right at idle. I can rattle on for days about it but the book will learn ya right =) then after all that u take and toss it out and get u a TBI setup from a mid to late 80's and never look back (its Cheap)
Thanks for the good info. I will probably get the book if it is that technical (or sounds that way). I sure have a lot to learn!!!
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Old 03-29-2011, 02:07 PM   #18
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Re: Holley Carb Tuning???

Y a Know I forgot a good bit to know. There are emulsion tubes that let air mix w fuel from up top at the air horn. If u all have leaky air filters You can clog those very easy with dirt and it will run poorly at idle and just off as well.
So Use those air filter base gaskets and make sure u have no holes in the filter base lid or elements =)
BTW Im an FI guy what am I doing here
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Old 03-29-2011, 02:23 PM   #19
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Re: Holley Carb Tuning???

first thing,, clean that pig..
get a can of carb cleaner..
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