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Thread: holley carb issue

  1. #1

    holley carb issue

    im not to good with the hole carb deal more into fuel injection an turbos some what knew to carb an spray
    i have a holley 80 582 witch is a 750 dom with mech secondarys
    it seems to spit back an pop somtimes when i stab it
    no vacumm leaks
    no fuel leaks getting twisted
    its on a ls1 with work in a mustang
    any ideas or input would be helpful

  2. #2
    sounds like a lean issue. how far out are your mixture screws what jets any power valves. need alittle more info to help. could be squirters too small

  3. #3
    Senior Member RACING JUNKIE jmarksdragster's Avatar
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    Not enough initial timing?
    Mark Whitener
    http://racingfuelsystems.myfunforum.org
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  4. #4
    its on a ls1 with that 6ls kit from msd
    the timimg been the same never change it from when i first tune it

  5. #5
    Senior Member RACING JUNKIE
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    The "spiiting back" tends to sound like a lean condition. I agree w/ the other post though... lets get some spec's: Jets size, PV or blocked? If PV, what size? Had a vacumn guage on it yet? Hows the float levels? Next, does it have a secondary idle adjustment? If so, no more than 1.5 turns there... that can cause hesitations/burps. Fuel mix screws... how many turns out at present? Ok, I am done w/ all the questions. Get some info & see if we can help more.
    "I would walk through hell on Sunday before I fear the enemy"

  6. #6
    Senior Member RACING JUNKIE
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    More info would be nice and is needed but from what I gathered it's definetly lean. Probably needs either the pump circuit fattened up, like bigger squirters nozzles front and back and or maybe a 50cc pump kit or you just may need to go up a few jet sizes in the primaries. It's kinda hit and miss, try one thing if it doesnt work put it back the way it was and try something else.
    Carbs need to be tuned to each indiviual set-up one that worked well on one motor might run like crap on yours, even if the motors are very similar.
    Also you need to proof-read your posts, before you click submit, tidy things up a bit, it's very confusing the way you stated your problem especially with all the mispelled words and your shop talk, not poking at you just trying to help.
    Goodluck, Cp
    ***IN GOD WE TRUST***

  7. #7
    Senior Member RACING JUNKIE
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    Good point CEPX, I have had to learn the hard way making multiple adjustments at one time. This rarely ever made any sense... as it hid the real issue even longer. I am not an expert, but he is exactly right... ONE ADJUSTMENT AT A TIME. Keep asking this forum until you get there, these guy's here helped me get my carb dialed step by step... keep diggin'
    "I would walk through hell on Sunday before I fear the enemy"

  8. #8
    Senior Member RACING JUNKIE
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    I would set the idle with a vacuume gauge ,and I would choose the pv by the vacuume gauge as well..with the car in gear at idle...I think a bigger squirter would probably fix it, but it may just be a bandaid to the real issue, if that makes sense..a big squirter may dump enough fuel in there to cover up the hesitation but still may not be "correct" or optimal tune on the carb...

    Completely agree with the above posters on one change at a time and most of all IF IT DIDN'T HELP PUT IT BACK BEFORE MAKING A DIFFERENT CHANGE

    Just my opinion

  9. #9

    carb

    From the info you give definatly going lean under wide open throttle condition, ie: stabbing it. Forget the power valve or main jetting to correct this condition as they only work with the high speed curcuit, which your not on yet when it pops. You need to work on the squirters on both the secondary and primary side. They may be out of adjustment, too small or you may even need to change the nylon cams that work the pump levers. Holley has a number of them that have varying slopes that change the pumps reaction time. You can tell them apart by their colors. I do agree with the other posts though, try one thing at a time so you don't get completly lost.

  10. #10
    Senior Member RACING JUNKIE
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    bigger squirters first, then tune from there, if you do not get a positive response.


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