carb idle question

Discussion in 'Engine Topic' started by cutty, Jun 10, 2016.

  1. cutty

    cutty Veteran Member

    Messages:
    342
    Likes Received:
    0
    Joined:
    Dec 12, 2008
    Location:
    ontario canada
    hi guys, got a question with the battle ive been having, ive got a 650 holley double pump on my motor, specs are 10.5 to 1 comp roughly, double hump heads, cam is a 540/540 lift, vac in idle in park is 9, gear 7, i cant get it to idle in park lower then 1100 gear 900 rpm,any lower it stalls, tested and retested for vac leaks, theres none, specs on carb are front jets 68 rear 78 front squirter 28 rear 31, power valve is a 4.5, ive tried putting my thumb over front bleeds, dies right away, idle mixture screws are 2.5 full turns,( just a 2 idle mixtures) it works dont get me wrong, but would like my idle down abit, timing at idle is 16, 36 total by 2800, any ideas?
     
  2. CorkyE

    CorkyE Veteran Member Lifetime Gold Member

    Messages:
    10,453
    Likes Received:
    508
    Joined:
    Nov 4, 2004
    Location:
    Ringgold, GA
    What's full specs on that cam? Mine doesn't like to idle much below 1K either. I have found that if you can increase base timing without going over on total timing, you will get a better idle. Also, going to assume you're not using full time vacuum advance either, that's hard to get a consistent idle with a big cam.
     
  3. G72Zed

    G72Zed Veteran Member

    Messages:
    1,258
    Likes Received:
    299
    Joined:
    Sep 8, 2015
    Location:
    Canada
    X2 ^

    Mine likes a min. of 22* at 1,100 rpm, 38* all in by 2600 rpm. I play with the spings only. I even tried 24-26* at 1,100 engine loves it, great throttle responce.

    I think allot of "carb issues" are actually timing issues, that's just my thinking.
     
  4. 80sz

    80sz Veteran Member

    Messages:
    3,216
    Likes Received:
    429
    Joined:
    Feb 2, 2014
    Location:
    Buffalo,n.y.
    I got same #s also, Almost same setup,540 cam,10.9-1 comp,vac same,rpm same,I can go little lower if I didn't have electric fan,it kicks on bogs me down 50-75 rpm
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.