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  1. #1

    Default Fuel flooding out of bowl vent tubes (Holley 4180)

    **EDIT** See post #20 for update. Still trying to find a good mechanical fuel pump!

    It's been a long time coming... here we go!

    After a lot of searching and finding just a single post with a similar issue (but different fuel pump) I'm taking a guess, but wanted some input.

    '84 GT convertible, 5 liter, 5 speed. Car was bought as a roller with no drive-train. Installed a roller motor, speed-density cam, Edelbrock performer intake, everything else stock. Pieced it together and got it to fire up.

    I bought the recommended Carter fuel pump (M60253) from rock auto. The car starts right up but within 3-5 seconds, I get LOTS of fuel flowing out of the top of the bowl vent tubes. Starts with the front tube, then shortly the rear tube flows as well. No vent plumbing hooked up yet, as I'm just trying to get it running and dialed in. Verified that the needle/seat & floats are not sticking.

    Tested with two carburetors (both 4180's) with the same results.

    Has anyone had an issue with these Carter pumps putting out too much pressure? That's the only conclusion I can reach. It's just pushing open the needle and seat and flooding out. I do not have a gauge or regulator since this was supposed to be OEM for what these cars are supposed to have new.

    The return line is hooked up and everything is clear... verified by blowing through lines and having an assistant listen at the tank with the cap off. I replaced the rubber sections of fuel line (using fuel-grade rubber hose) just to make sure nothing was collapsing. Pressure line from pump to carb is steel with no rubber.

    I originally had a cheap parts-house fuel pump that was dead on arrival... never pumped at all, so I read up on here and the Carter M60253 was recommended, so I went with it. Any other suggestions on different pumps or anything else I should check?

    **EDIT**
    The listing on rockauto's site has this pump's max pressure listed at 8psi. I'm guessing that's at high rpm and not idle. Most parts-house pumps are listed in the 6.5 psi range. Can anyone clear that up for me?
    Thanks!
    Last edited by graphicdesigner80; 10-28-2019 at 02:14 PM.

  2. #2

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    6.5 - 8 psi is in range for a carb application

    if I were to venture a guess I think the needle/seat is not installed properly or the float level is wildly out of range or the float is stuck!

    Thereís instructions with the carb kits for initial settings then you are supposed to dial the floats in through the site hole.

    Itís been a really long time but I believe back in high school my 351W with D0OE heads and offenhauser 360 degree intake ran 8 psi at idle and went as high as 10 past 6000 with the pump my dad helped me select. I had a few needle/seat setups fail but when they were good they held with the float just fine

    sorta miss the ol gun boat but if I hadnít traded it I wouldnít have my Four Eyed fox. that damn Galaxie my 351W was in ran like a top. 13 second time slips out of a 5500 lb gun boat with AC and full interior. It had my dad and I impressed for the early 90ía anyway..... idiot that bought it eventually pulled the 351 and dropped my motor into an early four eyed fox (which is what I always wanted to do) the he promptly wrapped that stock suspension pos around a pole. (Very sad, got killed doing it)

    crazy turn of events, Iíve had the chance to buy both my motor and my old car back over the years and I havenít done either ....

    Back when I had it I went to an AFB on that engine because atomization when it was cold was better than it was with the Holley 650 double pumper I had bought for it.

    You know atomization vs runner length sucks when raw fuel is dumping out the exhaust on the ground that you could light on fire and it would still lean out an quit, but thatís the joy of a tunnel ram in -20 degrees F weather! Stupid HS kids, even me
    Last edited by erratic50; 07-08-2019 at 06:23 PM.

  3. #3

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    Maybe try a pressure regulator to assure you have correct pressure going in?

  4. #4

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    Thanks for the suggestions. I suspect the pump is just putting out too much pressure (even at idle). Both holley's I tried did the exact same thing. When i took them off the car, I could flip them over and not be able to blow through the fuel inlet, so the needle/seat seemed to be working.

    What mechanical fuel pumps are y'all running? I'd prefer to just get the right one and not have to mess with regulators and all the plumbing involved.

  5. #5

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    FWIW, I recently put a guage on my fuel line. The stock replacement mechanical fuel pump on my 80 (brand new) puts out about 8.5 psi consistently at idle or when you rev it up a bit

    I decided to get a summit fuel regulator and dialed it back to 6 psi for my edelbrock carb as it states several places you shouldn't run any more than that. I didn't have any issues but I thought better to regulate it down and be consistent. The Summit reg is not outrageously expensive and has worked well so far.

  6. #6

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    Quote Originally Posted by at_the_junkyard View Post
    FWIW, I recently put a guage on my fuel line. The stock replacement mechanical fuel pump on my 80 (brand new) puts out about 8.5 psi consistently at idle or when you rev it up a bit

    I decided to get a summit fuel regulator and dialed it back to 6 psi for my edelbrock carb as it states several places you shouldn't run any more than that. I didn't have any issues but I thought better to regulate it down and be consistent. The Summit reg is not outrageously expensive and has worked well so far.
    Interesting. I was thinking about at least temporarily plumbing up a gauge to see what's going on with the fuel pressure. What pump are you running?

  7. #7

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    Im not 100% sure on the pump. It was a NAPA replacement for an 83 mustang I think. There is no return line just in and out.

  8. #8

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    It might be a Carter

  9. #9

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    Go the the hardware store and buy some barbed fittings and a t-fitting so that you can temporarily replace the steel feed line with all rubber hose. This way, you can install a t-fitting inline with a vacuum/pressure gauge. You will likely see the needle pulsate at low RPM and not steady out until you rev it up.

    If I was in your situation, this is what I would do...
    1. Install a t-fitting inline and check fuel pressure
    2. Drain the carburetor and crank the floats way, way down. Leave the sight plugs out and run the engine (be ready to contain fuel if it comes out)
    3. Submerge the floats to see if they are compromised

    Beyond these steps... there's really not much else that I can think of at this moment. For what it's worth... I just installed a QuickFuel non-return regulator to cure the same problem you are experiencing.
    1983 Ford Mustang 'Dominator' GT
    1999 Ford Mustang GT 35th Anniversary
    1969 Ranchero 500
    1968 Ranchero 500 "Hot Chocolate"

  10. #10

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    There are four conditions that will allow non-stop fuel entering a Holley float bowl, with procession to fountain-ing outta the vent tube:
    - garbage stuck between needle and seat, holding needle open off the seat...
    - split, worn out, or missing needle and seat o-ring allows fuel past...
    - float not floating, or not installed correctly or has come off it's pivot from incorrect installation with small e-clip...
    - float set too high, not allowing needle and seat to close

    Check this one out... couple years ago, a fellow actually had the feed line from the fuel pump connected to the big front vent tube of a 4180... fantastic amount of gasoline jetting up outta that baby!

    8psi isn't enough to overpower a float in working order that is set somewhere in the range of being able to close the needle and seat... though 6psi or less is better...

    ... be careful if you do adjust a needle and seat way, way down... I helped a neighbor a week or two ago with a '74 Corvette running like a mechanical a$$hole in general... lol... both Holley bowl fuel levels WAY down... adjusted the rear up, fine... adjusted and adjusted and adjusted the front up, no fuel level rising up... puzzling... removed screw and nut... somebody cranked the front needle and seat so far down in fact, that the adjuster nut was no longer capturing it, doing anything... lol... this after the car had apparently been to 3 or 4 "experts" around the city... fixed that problem, set primary float/fuel level, set idle mixture screws, removed the approximate 0.015" of clearance some "expert" adjusted into the accelerator pump mechanism AT IDLE, lol.... told him to take it for a rip now and see how it works... jaw-drop face accompanied with "it's a whole different car now, Mike!"... lol... double check all basics first, like float and needle and seat condition/function/adjustment...

    With a scenario like yours, obvious non-stop fuel flow up outta vent tubes... the very first thing I would do is pull out needle and seat/s, look for debris blocking open, or for split/worn/missing o-ring... if that's no issue, then the float is not floating or is adjusted too high...
    Last edited by Walking-Tall; 07-10-2019 at 08:50 AM.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  11. #11

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    Thanks for all the suggestions fellas. Was planning on going though the carb anyway as it has sat for an unknown amount of time. Bowls look clean, but you never know.

    I've searched around on here for a recommended kit to rebuild my 4180... can't seem to find anything. Was looking at this:
    https://www.amazon.com/Holley-3-1346...8FAEMQFS2CARN7

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    And this for a pressure gauge: https://www.amazon.com/dp/B000BPZ4SW..._t2_B000N8ISFS

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    When i get the carb apart, I'll definitely verify the floats are good and adjustment is correct. Seems like a lot of mechanical pumps these days are hit & miss. I'll buy another one just in case mine is too high on pressure.

  12. #12
    FEP Power Member qikgts's Avatar
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    Rockledge, FL
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    That is the rebuild kit to use. Can't beat original Holley kits. Just follow the instructions and you'll be fine. If you have questions ask away. You'll get good answers here.
    '85 GT

  13. #13

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    Quote Originally Posted by qikgts View Post
    That is the rebuild kit to use. Can't beat original Holley kits. Just follow the instructions and you'll be fine. If you have questions ask away. You'll get good answers here.
    Appreciate it! I'll report back with results.
    '84.5 GT vert / roller 5 liter 4v / t5
    '86 LX coupe / 331 / t5
    '86 F-150 - 5 liter / efi / aod
    '56 F-100 - 272 y-block / 3 on the tree

  14. #14

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    This probably doesn't get asked much anymore... My carb still has the plugs over the fuel/air screws -- all 4. Should I bother to mess with them? I don't want to ruin a perfect base plate, however i'd suspect that they will need adjusting since my motor is not stock.

    Does anyone remember how they went about removing these? Drill? Torch? They look like lead plugs.

    Thanks!
    '84.5 GT vert / roller 5 liter 4v / t5
    '86 LX coupe / 331 / t5
    '86 F-150 - 5 liter / efi / aod
    '56 F-100 - 272 y-block / 3 on the tree

  15. #15

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    Ahh - Diving into the deep end of the 4180. Think of the thing's you'll learn.

    Plugs - not lead. Hardened steel. The easiest way to remove them is to drill a small hole in the bottom of the base plate. Might need to be about 3/16" diameter and put it 3/16" from the end of the boss. Drill straight in. This should put you in the gap between the plug and the screw head. Tap the plug out with a pick or something similar. This way the appearance of the carb will be unaffected.

    The passages could probably stand a cleaning. I've had mine get blocked just from sitting over the winter. You may also need to check into upsizing your metering jets and the accelerator pump squirter.

    If you notice a stumble at barely open throttle, upsizing the jets will usually solve that. Changing the squirter to a larger size is the easier way to help take care of throttle opening hesitation.
    W

    As always, "It ain't what you don't know that gets you, it's what you think you know that just ain't so."

  16. #16

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    The inability to adjust idle mixture (with those dumbed-down mixture screws, inaccessibly hidden by harder-than-the-hubs-of-hell hardened steel "anti-tamper" plugs) with today's varying amounts of moonshine in the "gasoline" isn't a good thing at all... never was a good idea, like lots else within 4180's, another of a half dozen or so basically inaccessible dirt traps in them. Access the idle mixture screws as outlined above (be careful to retrieve and not lose the tiny springs that are in there too with the mixture screws), clean and blow the living daylights out of everything, add new mixture screw o-rings (which will now serve a purpose when the steel plugs are no longer in place but in the garbage, LOL!) onto cleaned mixture screws... reinstall, adjust rears 1/4-1/2 turn out and the fronts to 1-1/2 turns out... proceed with more precise adjusting of them when the vehicle is well up to operating temperature.

    Changing main circuit jets has no affect to idle/transition, idle/off-idle. Accelerator pump shooter, cam, and adjustment do.
    Last edited by Walking-Tall; 07-14-2019 at 06:44 AM.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  17. #17
    FEP Super Member gr79's Avatar
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    I use the box wrench and this 6" screwdriver to set Holley ext adj float level. Bought around 1971.
    Full size handle, short stubby wide full size blade fits center pivot float screw slot and sight plugs perfectly.

    Pic of a Craftsman-9-41586 Slotted-Screwdriver
    Attachment 128663

  18. #18

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    You may wish to check out this seller on Ebay. Sells genuine Holley parts. Even things like 4180 specific idle mixture screws.
    This kit contains the 1985 and newer choke pull-off diaphragm.
    You may want to contact him for the kit required for the 1984 and older units.

    https://www.ebay.ca/itm/Holley-4180-...53.m1438.l2649

  19. #19

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    Thanks for the tips. Very helpful.

    It's pretty obvious that I'm pretty green on the 4180. I've messed with a few 4150's, but this seems to be quite a different animal inside... especially dealing with the plugged fuel/air screws.

    I bought my car as a roller with no drive-train. It's been quite the adventure gathering everything to get it running again. Hopefully it's close. Owned since '08 and have yet to drive it!
    '84.5 GT vert / roller 5 liter 4v / t5
    '86 LX coupe / 331 / t5
    '86 F-150 - 5 liter / efi / aod
    '56 F-100 - 272 y-block / 3 on the tree

  20. #20

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    Many moons later, I'm back at it and now have the car at the house so it can hopefully get this solved.

    Carb rebuilt with the recommended Holley kit. Pump still overpowering needle & seat causing fuel to spill out the vent tubes. The only way this could be stopped was to crank down both float levels to nearly starving the carb out. It runs, but obviously not worth a crap.

    Hooked up my temp rubber line with pressure gauge and cannot get a pump that puts out less than 9 psi. Most put out 12-14 psi.

    The carter pump that everyone seems to recommend on here puts out 14 psi at idle. What the heck?!?

    I've verified and confirmed that my return line is not clogged and even bypassed it by running an open hose to a container and retesting all my pumps. Same high-pressure results on every single one.

    Thinking about trying this one - https://www.summitracing.com/parts/sdk-c5az-9350-b. Doesn't have return provision, but is a decent brand and claims to put out 6.5 psi.

    What are y'all running? Does anyone make a pump that doesn't cost $150+ that's guaranteed to put out less than 6.5 psi? Are all these mechanical pumps made in Asia now? Very disappointing.

    Suggestions?
    '84.5 GT vert / roller 5 liter 4v / t5
    '86 LX coupe / 331 / t5
    '86 F-150 - 5 liter / efi / aod
    '56 F-100 - 272 y-block / 3 on the tree

  21. #21

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    I'm using an O'reilly Precision mechanical fuel pump and cheap Quickfuel non-bypass regulator inline. Works great turned to 5.5 PSI. I was having the same problems you described and cured it this way.
    1983 Ford Mustang 'Dominator' GT
    1999 Ford Mustang GT 35th Anniversary
    1969 Ranchero 500
    1968 Ranchero 500 "Hot Chocolate"

  22. #22

    Default

    Quote Originally Posted by 99GTMichael View Post
    I'm using an O'reilly Precision mechanical fuel pump and cheap Quickfuel non-bypass regulator inline. Works great turned to 5.5 PSI. I was having the same problems you described and cured it this way.
    Interesting. Any pics of your setup? Happy with the quality of the regulator?

    I'm not anti-regulator, just seems disappointing that the pumps out there don't produce their advertised ratings.
    '84.5 GT vert / roller 5 liter 4v / t5
    '86 LX coupe / 331 / t5
    '86 F-150 - 5 liter / efi / aod
    '56 F-100 - 272 y-block / 3 on the tree

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