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holley carb help

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Old 02-06-2006, 08:36 PM
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Default holley carb help

ok..im super new to carburetors..i have only ever messed with fuel injection..(no old hot rodders around to show me the way ) anyway i have a pretty standard universal carb on my daily driver..its the holley 80457s..(600cfm vaccum secondary elec choke carb) my question is, it hasnt ran to its best potential due to me not being able to fully tune it..well now im trying to slowly learn about them and how to work on them..(its f##ed up now)..its running pig rich and smells like its just dumping raw gas through the tailpipe..ive been reading and reading and have discoverd that i need to check my needle and seat. Ive learned that i must pull the primary fuel bowl to gain access to this ,.and i will need to bowl gaskets. I dont belive that the carb needs rebuilt, its only about 1.5 years old. my question is this, a while back i was messing with it, (before i did any research,live and learn) and i believe i messed with the screw on the top of the bowl. I belive this to be what holds the float in place or such..anyways my carb is shitty and doesnt have the adjustable float, or sight plugs for that matter..since its not adjustable, is there any certain torque or anything i can go by to make sure this is right? also, i have read about acc pumps and tuning..my buddy was fumbling with the pump arm adjsting nut i believe. i would like to put this back to factory..i have read something like 15 thousandths from arm to nut or something..i know most dont do it like this..how do you do it correctly..just by feel for play in the arm or what? soory so long.im still trying to learn..
matt
Old 02-06-2006, 09:55 PM
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with your motor running take out the sight plug and see if gas runs out or not.i usually set my floats right below the hole so that will tell if your float is high or not. .015 sounds about right for the accelerator pump arm.is it running rich when it's just idleing or all the time ?
Old 02-06-2006, 11:00 PM
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thats what im saying..there is NO float adjustment on mine.. hence the reason for the lack of the sight holes (i guess? ) i just think that a while back i was messing around with **** and may have turned that screw not thinking..since there is no adjustment i would assume it doesnt matter. i have no idea..i was going to just get one of those street avenger 670's but i would hate to waste money on that when im sure this one will work..i just need to know.1) if there is a procedure or distance that screw has to be in, 2) how to adjust the acccelerator pump cam, ..i think i can do that by going over what i have read,,block the throttle wide open, adjust the nut to where theres .15 clearance bw nut and cam. here is a link to the manual for that carb if anyone would like to see it..as a side note..when i purchased this unit from the speed shop a year and a half ago..it was one that was remanufct.by holley..dont know if that makes a dam or not..i would like to think it was as good as new when i got it..
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http://www.holley.com/data/Products/...199R7948-5.pdf
Old 02-06-2006, 11:04 PM
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edit: it runs super rich at idle but runs rich just normally as well..i know i need to set the idle mixture screws as ive fubbed with the idle and not re-adjusted them..i know this needs to be done, but it was running really rich before that..all i can think of is there is trash in the needle/seat assembly. I have a guage on the fuel pressure and its right at 6.5. sometimes it seems if you listen hard enough..you can hear what seems to be like air leaking from inside teh carburetor with the fuel pump running ..you couldnt hear it if the truck was running..dont know if thats related or not. also i think i need to go down or up on my power valve..my cam pulls about 10 at idle on the vac guage and i ve never changed the pwr valve out, nor the jets..like i said , i have a lot to learn and need to get started if i want it to run right.
thanks for any help
matt
Old 02-09-2006, 11:45 AM
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ttt for me..old hot rodders..anyone
Old 02-09-2006, 05:47 PM
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get you some blue gaskets,those are the reuseable ones. i would jet down a couple sizes and then bottom out your air screws and back them out the same amount with the vehicle running until it idles the best.you should only have around .015 thousandths clearance with the accelerator closed on the pump arm.usually when the needle and seat aren't shutting off fuel it will flood terribly, probably enough to kill your engine.



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