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Holley 94's running too much fuel off idle, pressure?

Discussion in 'The Hokey Ass Message Board' started by BobbyD, Sep 2, 2007.

  1. BobbyD
    Joined: Jun 6, 2005
    Posts: 581

    BobbyD
    Member
    from Belmont NC

    This thing will idle like a dream, and cracking the throttle hard sounds good, but just off idle, around 1500 or so its rough as hell, and looks like its dumping way too much fuel while looking down in the carbs. Too much fuel pressure?, floats seem OK but maybe, what?? I read thru alot of posts and still I'm a little lost. Help!!
     
  2. Flatman
    Joined: Dec 20, 2005
    Posts: 1,975

    Flatman
    Member

    Check the power valve in the carb. It may be blown and dumping fuel. What setting do you have the accelerator pump lever in?

    Flatman
     
  3. BobbyD
    Joined: Jun 6, 2005
    Posts: 581

    BobbyD
    Member
    from Belmont NC

    2 new power valves, 4.5s in them, 48 jets and the acc. pump in the middle hole. There on a regular Offy intake, seems i read somewhere where this may affect pressure due to height of manifold??
     
  4. Flatman
    Joined: Dec 20, 2005
    Posts: 1,975

    Flatman
    Member

    Are you running a stock pump? They usually provide enough pressure for two carbs. Are you running tandem or progressive linkage?

    Flatman
     

  5. BobbyD
    Joined: Jun 6, 2005
    Posts: 581

    BobbyD
    Member
    from Belmont NC

    Stock pump, a new one, and tandem linkage. Also, the vacuum advance was hooked up to manifold vacuum, which I thought was wrong, its now on the rear carb, could this maybe be causing this?
     
  6. Flatman
    Joined: Dec 20, 2005
    Posts: 1,975

    Flatman
    Member

    The stock distributer needs the ported vacuum, so you were thinking right:D . However, with two carbs your vacuum signal will be about half of what the distributer needs to see as you are running tandem.
    I have the same set up, but plan on getting a mechanical advance distributer from GMC Bubba, then I don't have to worry.
    I don't think this is causing your overfuelling problem though. The accelerator pump bridges the gap between the idle circuit and the main circuit so you don't get a flat spot. Try shifting the pumps to the lean hole and see how it runs. The main jets will only pass fuel according to the air passing through the carb, two carbs=half the normal airflow per carb.

    Flatman
     
  7. BobbyD
    Joined: Jun 6, 2005
    Posts: 581

    BobbyD
    Member
    from Belmont NC

    Think putting a pressure regulator between the pump and carbs will help any?
     
  8. Flatman
    Joined: Dec 20, 2005
    Posts: 1,975

    Flatman
    Member

    The stock pump puts out around 3psi, which shouldn't be too much in the way of pressure. Are you 100% sure of the float levels? These things are prone to flooding. Mine have this tendency to leak fuel all over the manifold externally:mad: A regulator certainly wouldn't hurt, but probably isn't nescessary. How did you sync the carbs?

    Flatman
     
  9. jalopy43
    Joined: Jan 12, 2002
    Posts: 3,085

    jalopy43
    Member Emeritus

    I tried 97's, 94's back 20 years ago. I couldn't stop them from dribbling fuel on the manifold either. That's when I started to carry a fire extenguesher. I would say power valves are the culprit(off idle,the vacuum drops, they will pour fuel in) I helped it a little by replacing them with plugs,and jetting up(94) to #56 jets. It ran a little rich at cruise though. I finally 'solved 'the problem by switching to a wcfb four barrell. No, not as cool looking , but runs nice,and with power... good luck...
     
  10. 3blapcam
    Joined: Jul 15, 2004
    Posts: 531

    3blapcam
    Member

    Are the power valves the early style or did you buy off the shelf valves? My buddies flatty had this problem with BG powervalves. We even went to 3.5's to keep them from openning too soon, but in the end we swapped them out for a plug and a stock PV and it responded very well to the change. We ended up jetting it way down also. I would start by dropping the vacuum advance distributor because that can be causing a headache in it's own. We've never had any issues with fuel pressure and it's running the stock pump. I don't think I'd chase that route. Hope this helps...
     
  11. BobbyD
    Joined: Jun 6, 2005
    Posts: 581

    BobbyD
    Member
    from Belmont NC

    I sync'ed them by ear, I loaned my uni-sync, well we all know how thats goes, anyway I guess I should pull the airhorns off and check 'em yet again. I don't have any external leaks at all. I've put 94's on alot of motors over the years and have never run into this. What do you recommend for float settings?
     
  12. Flatman
    Joined: Dec 20, 2005
    Posts: 1,975

    Flatman
    Member

    The float level, measured between the machined surface of the bowl cover and the top of the float, should be 1 11/32" for the AA-1 and 2100 carbs. The 2110 sets at 1 15/32", and the IHC truck 2110 sets at 1 5/16".
    The float drop should be 1 7/16" for the AA-1 and 2100 carbs, and 1 3/4" for the 2110 carbs. this is measured with the float hanging freely from the bowl surface to the bottom of the float.
    I'd try the lean accelerator pump link setting (hole closest to the throttle shaft) and drive it, see if it makes a difference.

    Flatman
     
  13. hotrodder51
    Joined: Aug 22, 2007
    Posts: 12

    hotrodder51
    Member

    Block off the power valve on the secondary carb, and use a progressive linkage. I did this on my AV8 and all problems were salved. Leave the 4.5 power valve on you primary carb. I use an original Eldelbrock Sling Shot so height has nothing to do with it. Contact Vintage Speed for advice on 94's, Charlie is a great source.
     
  14. BobbyD
    Joined: Jun 6, 2005
    Posts: 581

    BobbyD
    Member
    from Belmont NC

    Well, I've reset the floats and checked the PVs, no change. This thing run fine before, the front carb is the one orginally on it, and the rear come off my F1, so I know they were both good before. What the hell??
     
  15. BobbyD
    Joined: Jun 6, 2005
    Posts: 581

    BobbyD
    Member
    from Belmont NC

    Put a regulator in line, problem solved, too much fuel pressure.....Thanks fo all the help!!!
     
  16. Dirty2
    Joined: Jun 13, 2004
    Posts: 8,903

    Dirty2
    Member

    Thanks for that info. I needed it.
     

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