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Technical Holley 94 secondaries sucking at idle

Discussion in 'The Hokey Ass Message Board' started by hb32, Apr 18, 2014.

  1. Carbs are rebuilds from a member on the HAMB. Reading lots of info on the 94 thread as well.
    Idle is low and tried playing with the mixture screws. When I get it to idle enough to keep running, I place my hand over either secondary and engine stumbles plus can feel noticeable draw with throttles closed. No idle circuits on secondaries and using a progressive linkage. Also, off idle around 1500 rpm, significant bogging like it wants to stall but responsive after that. Significant stumble after I release throttle to the point of stall and hard to restart without throttle to floor and lots of cranking. I have not test driven yet.
    Bases are originals that have been cleaned up and I modofied the primary for vacuum advance.
    After some reading on the HAMB, everything points to the plates not sealing in the bores, am I on the right path? Would the machined bases from Charlie Price fix my issues?
     
  2. OK the best way I know how is to pull both end carbs. Use a block off plate and close off both ends. Now get the motor running and adjusted. Now replace both end carbs. Turn the idle screws on the end carbs so the plates close. Adjust your progressive linkage so all carbs are full open at full throttle. Also make sure the accelerator pumps on all carbs squirt when the throttle blades move on each carb. This should get you in the ball park.
     
  3. ^^^^good advice!
    Check with Dickster....he may have the goop that was used by GM back in the day to seal the secondary blades. I got my last off the net and have used it twice with good results. Secondary's have to seal tight or you will always be chasing issues
     
  4. 57Custom300
    Joined: Aug 21, 2009
    Posts: 1,424

    57Custom300
    Member
    from Arizona

    Good advise x2. I spent a week getting mine to run right. Picked up secondaries from Charlie, adjusted the primary carb w/the sec. blocked off then reinstalled the secondary carbs. I ended up with a lean condition at idle that drove me crazy. I could feel a slight vacuum on the secondary carbs but the idle speed would pick up 1000 rpm's when I hand choked it. Long story short, I had a worn throttle shaft bore on the primary carb. Put the throttle shaft in another base & it fixed it. Don't know why the leak didn't show up when it was blocked off but it run fine now.
     

  5. Ole don
    Joined: Dec 16, 2005
    Posts: 2,915

    Ole don
    Member

    The simple fix is to open up the idle circuits and open the mixture screws about 1/8 turn and tune from there.
     
  6. Working with the dickster on this one.
     
  7. Blocked off the end carbs as suggested and found the problem after introducing each carb individually.
    Dickster is fine tuning the plates and should be back up and running as soon as they return.
     
  8. Cooooooooooooool
     
  9. Update on the carbs. Sent the secondaries bases back for rework as the gap was kind of too much around the plates.
    Quick turn around and put them back on shortly there after. Car is running decent and managed to put 500 miles on it last weekend. Still backifiring thru the exhaust on decel under load which I have determined is my headers leaking where the 4 tubes meet the collector. I had them welded up last year and thought it was solved but still an issue...new ones coming with a warranty of sorts this time as they were used. Car is bucking, for lack of a better definition, under load which I am slowly resolving as well. Primary came with 54`s for jets and they are not providing enough fuel. Swapped them out for 64`s and then 66`s. Improving but still there so will try 70`s when I get a chance. Car is very driveable and acceleration is very impressive when the secondaries starting dumping fuel :D:D:D
     
  10. kuhn1941
    Joined: Feb 15, 2013
    Posts: 192

    kuhn1941
    Member

    I am learning on my 248 straight eight buick too . I built the intake and exhaust plus rebuilt carbs myself and using model 59 carbs on the ends with a 7h model for primary . My rear carb has the leak past the throttle blades which makes it so my idle doesn't need to be set . I am running 51 jets in all three and no power valve front and rear , but a 8.5 power valve in center carb - after checking the vacuum in the intake . My distributer vacuum advance makes a huge difference in the smooth Ness to the transition of throttle . I'm still learning good luck on yours !

    Posted using the Full Custom H.A.M.B. App!
     

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  11. clem
    Joined: Dec 20, 2006
    Posts: 4,188

    clem
    Member

    If having to enlarge primary jets to such a size why not go to a bigger centre carb, or run 2 outside carbs as primaries and tip in middle carb as secondary. Just a thought ! I realise that it is probably a bit late to go down either of these paths.
     
  12. Thanks and that was an option I did not think of having the secondaries run as a primary.
     
  13. clem
    Joined: Dec 20, 2006
    Posts: 4,188

    clem
    Member

    I had a bit of a alternative motive for suggesting this. I tried to set up straight linkage on mine and car ran better when I took off centre carb so I may tip in middle carb progressively. Thought that I might generate some helpful comments. I will start a thread on this.
     
  14. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,681

    Bruce Lancaster
    Member Emeritus

    A traditional flog on triples with secondaries is to very slightly loosen the screws holding throttle plates to shaft and jiggle, poke, and prod the plates while peering through the thing at a light until you achieve a good seal. Or don't, and try a different base! I think the plates may well have been select fitted originally, as unlike with Stromberg Ford said not to mess with them and to replace the whole throttle body if there was a problem...something that is now a bit impractical! Obviously, a loose shaft makes everything hopeless.
    Those jets worry me...the need for jets bigger than about 051 suggests that something is wrong somewhere else. The thing should not even run with jets in the 60's. This needs some analysis!
     
  15. saltflats
    Joined: Aug 14, 2007
    Posts: 12,594

    saltflats
    Member
    from Missouri

    I think I would be looking at the spark plugs maybe a different heat range or may just play with the plug gap.
     
  16. Thanks for your input Bruce and appreciate it.
    Secondary bases are now a lot better and thought I was fixing a "Bucking" problem so started upping the jet sizes to see if it would help. After reading some posts determined it was fuel pressure. Increased pressure and the problem as changed considerably for the good so will now start jetting down. Primary came with 54`s and agree that 68`s is a drastic increase. I read an article of a similar set up on a y block using 66`s for the primary and 61`s for the secondaries. Engine is a roller 5.0 with a more aggressive then stock cam, aluminum heads with bigger valves.
    Car actually runs well with the 68`s. I have 56 and 57`s that I am gonna give a try.
    Once again appreciate your knowledge Bruce and feel free to add your thoughts.
     
  17. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,681

    Bruce Lancaster
    Member Emeritus

    For a normal '39-50 or so 94 (model ID is on left of bowl) the thing should be happy somewhere close to 50 and starting to smoke black at 54! Look into float level. fuel level if you can rig a sight glass, and try to figgerout why it needs such big jets. I would believe that the jets are compensating for something wrong...
    3 94's are not really much carb at 5 liters, and should work fine fairly close to stock. I personally would try for a good throttle plate fit to allow close adjustment and go for straight linkage.
     
  18. Installed 56`s and bucking is back big time so put 66`s back in to minimize the problem.
    So, should the primary plates seal as well as the secondaries as in no gap when held up to the light? If this is the case, that is where my problem lies. There is a considerable sucking through the primary at idle as well, which I thought was normal. Sorry for the lack of knowledge on these carbs and learning as the days go by...
     
  19. Don't apologize...I am trying to troubleshoot mine along with you and appreciate the questions and feedback!
     
  20. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,681

    Bruce Lancaster
    Member Emeritus

    Primary carb of course runs with plates open a bit. Fitting them to seal first may help, though, in getting settings even.
    I personally would try to get all 3 sealing then get straight linkage. Throttle openings need to be very small with all 3 working, so gettem to seal, then install with slight opening, keep dialing down carb idle setting on each and resetting mix screws to their happy places at each change until you get the whole mess down to a sensible idle speed. Best is actually to leave linkage loose, hook up simple springs so carbs can't open up on their own, don't tighten on linkage until idle is right.
     
  21. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,681

    Bruce Lancaster
    Member Emeritus

    What carbs are you running? Info on left of bowl, "94" is pretty meaningless. Whatever they are...66 jets are insanely huge and should not even allow the car to run above idle! Something is STRANGE here.
     
  22. kingofthecrate
    Joined: Sep 25, 2012
    Posts: 49

    kingofthecrate
    Member

    IM having the same issues as the OP. the bases charlie sent to me are binding with the linkage going to the accelerator pump arm. I am about to set fire to this car after spending almost 1000 bucks on having the carbs redone by a guy who knows how to build carbs but has never worked on a 3x2 set up and the other half on parts from vintage that aren't fitting. still waiting for a call back from vintage to fix that issus as well.
     
  23. kingofthecrate
    Joined: Sep 25, 2012
    Posts: 49

    kingofthecrate
    Member

    BTW.. anybody know what this vacuum port is for? the new gasket kit I was sent clearly didn't seal over that hole.. holley 94 ecg-6
     

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  24. I agree with everything on Bruce's post #14. The jets are super large and there is something going on elsewhere. Have you tried driveing it without the aircleaners to eliminate any restrictions there?

    Regarding the throttle plates, it is imperative to have them comepletly shut on the secondary carburators with a progressive linkage. One trick I learned is to actually open up the holes the screws go through on the plates themselves, slightly, so as to allow a little more adjustment of the plates fit in the throat. Do leave the screws loose and do your best to get them to a point where no light is visable around the edges of the discs when looking through the base before tightning the screws. You realize the discs only go in one way of course.
     
    Last edited: Jul 8, 2014
  25. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,681

    Bruce Lancaster
    Member Emeritus

    ECG question...the vac passage over to the side and up has something to do with an automatic choke setup that I have no experience with. Pluggit unless using on a stocy Y block with all that stuff! This isn't really a 94, it is a substantially bigger bore post-flathead carb. I think there are a few roaming the basement, but don't know much about them.
    All hotrod air cleaners are suspect until proven...carbs should be adjusted and tuned without cleaners, then if things change when you put them on...they are junk and need to be re-thought!
    No one in the "normal" mechanical world knows anything about carbs, because they went out of production use in the mid '80's...that leaves gurus and experts and crackpots, meaning you better learn something yourself. And learn to be suspicious of mail-order expertise...
    The Ford bulletins that explain the circuitry of Strombergs and Ford 94's are online now, and should be memorized. Once you know what each circuit and hole does you can start thinking coherently.
     
    kingofthecrate likes this.
  26. kingofthecrate
    Joined: Sep 25, 2012
    Posts: 49

    kingofthecrate
    Member

    you're absolutely correct Bruce and I have knowledge to myself very well regarding the carburetors I just did not have the tools to get all of the parts sandblasted and cleaned up and this guy was highly recommended by an old car builder as far as carburetor knowledge.

    I am actually driving over to the shop right now to explain a few things with him and figure out which steps we need to move forward with and I will talk to him about plugging those holes because the system does not use a vacuum choke any longer
     
  27. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,681

    Bruce Lancaster
    Member Emeritus

    This club site has posted the best carb bulletins for Stromerg and Ford carbs. Note that details and specs will differ some on later variants of the 94 family.
    Specifically, read the bulletins on 94 operation and circuitry before you get in too deep. Rebuild is well covered too.
     
  28. kingofthecrate
    Joined: Sep 25, 2012
    Posts: 49

    kingofthecrate
    Member

    You're right and I've read all of it. I just never found a detailed idea of the vacuum controlled choke on the ecg-6 holleys. So it was new ground for me.

    As far as what um finding. That vacuum circuit was plugged at the top of the base where the vacuum solenoid would mount. I'm still getting vacuum from the secondaries at idle. I'm trying a stronger spring to help keep hose plates closed. I also adjusted my timing and that made the biggest difference of all.
     

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  29. Carbs are EBU`s for the secondaries and a ECG5 for the primary.
    Car runs well with the 66`s but still a little bucking mostly when idling in lower gears, its a 5 speed.
    Ran a lot better with the 68`s so have no idea what could be wrong. Secondaries are definitely closed until 60% of primary on a progressive linkage. Very responsive on the primary and even better when the secondaries kick in. No bogging on acceleration. Engine is a 5.0 Ford with 220/220 duration 498/498 lift, heads are Edelbrock performers with 1.90 intake valves. I know that the headers are leaking where the exhaust runners join at the collectors and will be swapping in a new set shortly. Carbs are not totally level and not sure if this is causing me issues. Car reeks of gas on idle and after shutting it down but no leaks evident.
    Not sure what else to say.
     
  30. Still driving it and runs well.
    What could I be missing if 66`s are too big for the primary??
     

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