Holley 4150 dripping fuel from primary discharge nozzle?

Fuel and Air Systems

  1. Cope

    Cope Fusing with fire

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    Hi again folks, Im back with more carb issues.
    Im trying to set curb idle and found my passanger side primary discharge nozzle is leaking fuel.
    The driver side is dry.

    I did some web searching and found this to be semi common. Most posts.say to remove.the offending bowl and clean the needle adjust float.

    I did all of that and im still leaking. This carb was just rebuilt (by me) should I pull the needle again and clean it or?????

    I dont think Im passed the idle circuit yet but have not pulled the carb and looked and it is only one side.


    Im having to set curb idle to high and in drive I have to hold the car back with the breaks more than normal.

    Im pulling about 14 pounds of vaccum at idle and power valve is a 6.5.

    Vaccum advance is plugged and with the car in drive my timing is about 10BTDC.
    Cant see timing mark in park. Dose sound even close?

    650 DP on wyand pluss pluss on top of a 318.

    Thanks again for all the time and advice.
     
  2. 67Dart273

    67Dart273 Well-Known Member

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    Does this thing have bowl sight plugs? How is the fuel level? Is heat causing the level to rise? What's your pump pressure?
     
  3. Cope

    Cope Fusing with fire

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    No sight plugs just brass screws. I just adjusted the float with the car running and it was just weeping out.
    Fuel pressure set at 4PSI with a crappy Holley reg (not made in the USA)
    No return line but I do have the nice thick Holley base gasket with the metal anti crush.

    Thanks again.

    Car is a 71 Dart
    OEM mechanical fuel pump.
     
  4. Locomotion

    Locomotion Well-Known Member

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    By "discharge nozzle", are you referring to the accelerator pump nozzles? If so, you may be missing the little "needles" that go under the discharge nozzles. These keep the vacuum from pulling fuel out of them. At idle, they plug the passage. But the accelerator pump pressure simply pushes them up and allows fuel to squirt out when you mash the pedal.

    https://www.holley.com/products/fue...components/accelerator_pump_parts/parts/121-5

    Otherwise, you may be referring to the "booster".
     
  5. mderoy340

    mderoy340 Well-Known Member

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    check the airbleeds are clean. did you use the correct gasket power valve gasket?
     
  6. Cope

    Cope Fusing with fire

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    Sorry Its not the acell pump nozzle rather the ring that is centered in the venturi.

    While playing with it I noticed both nozzels in the primary side are dooing it not just one side.

    Also with the air fuel mix closed on the driver side the car will not stall?
    closing passanger side will stall the engine.

    air fuel screws are one turn out.

    Not sure what the air blead is or where its located or how to check?

    All gaskets are correct as far as I could tell uponn reassembly.

    Thanks again.

    This is a old 4150-4777. It came off my pops shelf so hopefully this is not why it got shellfed 30 years ago....?
     
  7. EL5DEMON340

    EL5DEMON340 Well-Known Member

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    Make sure the bowl vent is clear.
     
  8. EL5DEMON340

    EL5DEMON340 Well-Known Member

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    You said you have the idle higher than normal and have to hold it back with the brakes. You may have to start over on your tune. Make sure idle slots are fairly square. And start with the timing
     
  9. 67Dart273

    67Dart273 Well-Known Member

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    I think your float level is creeping

    "Brass screws," by the way, ARE "sight plugs," LOL

    might try a different needle, or just lowering the level.

    I haven't run a Holley in 30 years. I used to run the level just "before" weeping out if possible.

    Modern fuel does not help
     
  10. Cope

    Cope Fusing with fire

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    Thanks.
    So.with the car in park what number should.I be looking for?
    8BTDC?

    Can you explain squareing up the idle slots?

    I have the bowl off but its dark so in the AM im gonna try a new power valvean gasket, make sure the jets are tight, pull needleand seat an clean and reset float.

    If this the right thing or am I looking in the wrong place?
     
  11. EL5DEMON340

    EL5DEMON340 Well-Known Member

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    Look at the bottom of the throttle plates, bottom of carb,
    you will see a slot it should only show around .040 or be shaped like a square or just slightly rectangle. If it's a longer rectangle shorten it to square. Before you instal the carb blow it out with cleaner every hole in the metering block, take out your A/F screws and spray those, and also the 4 small air bleeds you see when you look down the primary side of the carb by where your boosters were leaking, they will be towards the front of the carb just above the boosters.
    As for timing if it's a mild motor with small cam set it at 12 to 15 initial, if a bigger choppy cam go 15 to 20 for starters.
     
  12. pishta

    pishta I know I'm right....

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    Had a Demon whose needle seats would not hold fuel back. Carb would load up at idle and slowly drown and die. You could see fuel pulling from booster in drops. Sounds like your level is high or pressure is too much but 4 is low even for a holley, they usualy like 7. 4 is for Edelbrock/Carters. Air bleeds are small holes right inside air cleaner base. I would look at meter block gaskets. they are about a buck each at a speed shop.
     
  13. the67fish

    the67fish Well-Known Member

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    adjust the accelarator pump
     
  14. flyfish

    flyfish C8H18+N2O = :-D

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    Squaring the idle slots.....Flip the carb, make sure this is only exposed enough to make a square (Arrow #2).
     

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  15. nm9stheham

    nm9stheham Well-Known Member

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    Per your description, the fuel is leaking from the auxiliary venturi's which are fed by the main jets.
    Possible causes:
    - High fuel level but that sounds OK with the fuel just weeping out of the sight plugs while running (post #3). That usually eliminates float issues or high pressure or a leaking needle valve.
    - Plugged air bleed(s); see post 11. Remove the metering block and squirt cleaner down from the top though the air bleeds and make sure cleaner squirts out in the holes near to top of the carb body where the block mounts. Then use that location to figure where the air bleeds go into the metering block and squirt cleaner into those holes; it should flow freely out of the main jets.
    - Wrong/bad metering block gasket blocking the air bleed passaage from the carb body into the metering block. Inspect as part of the above procedure.
    - Broken power valve diaphragm or bad gasket; inspect this. Perhaps just replace power valve.
    - Too high an airflow at idle just activating the mains due to throttle plates not closing; see the above post and also check the primary throttle action with the throttle linkage disconnected for smooth action.
    - Not being able to stall the engine with the driver's side idle mixture screw may be another symptom of the issue, or the driver's side problem is just worse (probalby is since it was easier to spot), or just may be that the screw's seat inside the base is fouled up. Remove that screw and shoot a bunch of cleaner in there and inspect for a burr or varnish or groove across the seat.
     
  16. Cope

    Cope Fusing with fire

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    Ok so I took the carb back apart cleand the metering block, air bleads and squared up the idle circut and now the car wont idle unless I hold open the linkage.
    Should I go in on curb idle or should I be adjusting something else?

    Thanks again.

    I owe all you folks a beer! Thank you. Just a little more tuneing and I think she will be there.

    The solution was adding timing and resetting that idle circut. It seems like a threw a lot of timing at it to solve the issue but its working so a test drive is in order!

    Thanks again for all the help.
     
  17. PocketAces

    PocketAces Well-Known Member

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    When I rebuilt my Carter, I had the same problem. Turned out I hadn't torqued down the new seats properly and it was leaking fuel through the seat threads.

    Not familiar with Holley's, but with the Carter, you can take the top off with the floats still attached and blow on the fuel inlet with your mouth. If it still leaks air when you lift up on the float you've got a problem with the needles and/or seats.
     
  18. 69MOPE

    69MOPE Well-Known Member

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    Square up the slot and locktite the screw. Adjust timing and mixture to get good idle. If you raise the timing you will get pinging. Have the dist advance modified to limit full timing to 34 btdc.-OR- you can also use an adjustable vacumn advance diaphram. Square the slot, adjust timing max to 34btdc without the vacumn advance hooked up, then hook up to manifold vacumn source and adjust the diaphram limit to the timing that makes the "happy" idle, that way you have 4 to 8 degrees btdc, cranking to start, "happy" idle timing when it starts( as high a setting that is needed, I have seen as high as 26 degrees btdc) and a max timing of 34 btdc. This way, you don't hurt the starter and no dist advance modifacation is needed.
     
  19. nm9stheham

    nm9stheham Well-Known Member

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    It sounds like you changed (fixed) something and now you can do the right adjustments. Is the leakage from the the auxiliary venturi's gone when you hold the linkage so it will idle?

    You may have to go back and forth with timing, curb idle, and idle mixture some as you change them. Just keep a good track of the changes you make with notes on paper so you can go back a few steps if need be.
     
  20. flyfish

    flyfish C8H18+N2O = :-D

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    Now that the T-slot is square, if it won't idle without pressing the gas it probably means it needs more air. Again, pull the carb off, flip it, there is an adjustment screw that will crack open the secondaries to let in more air (should fix this)...if this does not work there are other ways to get more air, but you should probably try this first...the other way I know of involves drilling the throttle blades, and should be a last resort.

    Here is a link with a picture of the adjustment screw I'm talking about (picture on page 2):

    http://www.onallcylinders.com/2013/...operly-set-up-the-idle-on-holley-carburetors/
     
  21. Cope

    Cope Fusing with fire

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    The leak os gone and the car runs like a raped ape.
    I never thought my shitty 318 could sound or run this good!

    I got a Pavingstone "emergency" that a custo needs handled but Im a gonna do a birn out later!
     
  22. pishta

    pishta I know I'm right....

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    tuned carb on a written off old motor=smiles! :)
     
  23. nm9stheham

    nm9stheham Well-Known Member

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    Cool beans! Curious: How did you finally fix the idle issue?
     
  24. Cope

    Cope Fusing with fire

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    Squareing up the idle circut was the root of the problem.
    after squaring up the idle circut I opend the air fuel mix up to 4 1/2 turns out just to get the idle circut flowing enough fuel to keep the motor alive. now Im backing down Idle mix and fine tuning the curb idle screw.

    If any of yall ever make it to lake tahoe I got cold beer for ya!

    Thanks again!

    EDIT-Cuz we all like picks.

    Idle circut when I pulled carb off.
    [​IMG]

    Idle circut set where is shoud be and will correctly meeter fuel.
    [​IMG]
    Still tuneing but getting way closer.

    I may end up orderig a set of main jets in 65 to replase my 67s but that decision will require a few more days of tuening.
    Cant make to manny hot passes before the neighborhood gets pissed!
     
  25. nm9stheham

    nm9stheham Well-Known Member

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    Just bolt a gun rack in the rear window and they should calm down... LOL . Good story... thanks for sharing, and the pix are very good.
     
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