Fuel float struggle

Its getting tough to do much beyond spitballing and wild ass guessing from afar at this point, which I hate. Clearly you have multiple issues conspiring in this nightmare scenario. One is fuel delivery to the carb. I suspect the fuel pump is malfunctioning, seeing as how it apparently can't provide more than a small quantity from a temporary fuel can or the tank. If two different sources give the same result, you pretty much have to conclude that the fuel pump isn't sucking like it needs to suck...which really sucks. Another issue is the ridiculously high engine speed with no ability to idle down while the engine is running. Is it because the carb mixture and idle speed settings are out of adjustment, or is it the result of some internal flaw, such as a fouled up or incorrect gasket? I have no way of knowing without being able to at least lay my eyeballs on the disassembled carb components.
Do you have a fuel pressure gauge that you could connect downstream from the pump? I suggest you buy a cheap electric pump for diagnostic purposes if nothing else. That might at least get a steady and adequate fuel supply up to the carb. What the carb is able to do with the fuel once it gets there is another thing altogether, but there's zero chance of it running if the fuel bowl won't fill.
 
thought 1: In an earlier post you stated that you cleaned the fuel bowls and metering blocks, but did not Clean the carb body.

Why not???

You are wasting your time by doing a half-axxed job on that carb.

A complete fuel system cleaning is required after a car sits for a long period as you stated in your first post.

thought 2: It appears the fuel filter is not getting fuel. I suggest you check your fuel lines as you could have a leak, allowing air to be drawn by the fuel pump instead of fuel.

thought 3: Fuel tank....fill it up with fuel so that you know It has an adequate supply of fuel. Get the correct fuel cap on that tank.

thought 4: The fuel pump has two check valves that control the flow of fuel. Lines hooked up in reverse will not pass fuel to the carb. Since you are getting some fuel then the lines are attached correctly. Check the volume (quantity) of fuel output for a set time period of pump operation to determine if the fuel pump is up to standards for that pump p/n. You will have to find this specification in your Ford mustang 289 manuals.

thought 5: When you find something wrong, no matter how small, fix it, do not jury-rig it or bypass it. Fix it. These small issues add up and compound themselves.

Good luck
 
Hi guys

looking for advice ; I have purchased a gallon can of berryman's chem dip. I wondered. I don't think that the carburetor ( a Holley 4150 ) has any aluminum parts. There is a restriction warning not to dip aluminum longer than 4 hours.

The young parts store clerk just motioned that same restriction without specifying aluminum. " just don't dip for more than 4 hours. " I certainly don't trust his experience if any.

Can anyone offer some advice in this process? I think I will have to remove the plastic black choke adjustment cap.......

Thx

lawrence
 
All plastic parts will need to be set aside. Most of the carb parts are cast zinc or steel. The throttle body is the only piece that May be aluminum. That part is easy enough to clean in regular solvent and/or spray carb cleaner chased with copious blasts of compressed air. The most important pieces to be dipped are the metering blocks and the main body as those contain all the tiny orifices that tend to get gummed up with fuel, grit and moisture contamination. Overnight soaking of those parts is not out of the question, followed by thorough water rinsing. Make damn certain all traces of water are removed before you begin the assembly process.
 
Hi trever

I question the water rinse. Water and gas mix is not a good idea. Could I not use something flammable/combustible. Such as paint thinner, isopropyl alcohol .... Hmm thats 70 % alcohol and what 30 water.. Not great either.

Perhaps remove some of the virgin chem dip for a second step dip or rinse fluid medium.


Then let it just let it drip dry.?

Thx

lawrence

https://www.youtube.com/watch?v=vadbu_buali

Just for fun. The empty fuel filter is not the problem. The pump fills a 18 ounce beer bottle with the filter on! In a few seconds. So I will proceed with the chem dip when I hear your reply.
 
There's nothing wrong with the water rinse so long as you take steps to remove all the moisture before the assembly process begins. This is done with compressed air and exposure to sunlight or even some time in the oven at lowest temp. Perfectly acceptable practice...otherwise I wouldn't have suggested it. What isn't good is to leave berrymans residue on the carb parts with no rinse cycle.
 
Hi trevor


I was putting the carb back together when I realized the "new" reusable gasket in the kit was actually blocking two of the metering block hole inlets .. Can you guess if this is a cause of a failed idle circuit? I wont get this back on the car until next week. But I am drilling by hand with a drill bit to open the gasket.. I wonder what I can do to seal the paper tears?

I was able to use a electronics air can cleaner and straw to easily!! Push air thru all holes in the carbs body and m block. I wonder if this is why I'm not getting squirt on the throttle!>

this closed gasket was in operation when I did the video on you tube and why I have never been back to speed?


100_7570.jpg


100_7572.jpg
 
You are using the wrong metering block gasket. The accelerator pump circuit has no sealing around the hole at the top of the power valve "window", so all your squirt is leaking out. The window should be flat at the top, not notched like the one you have in the picture. Also, do not make more holes than are there. The hole you made is right over the main well/idle fuel restriction. Instead of feeding to the ports in the venturi , it is dumping fuel. Fuel is fed from the jets, not holes. Use gasket Holley p/n 108-29 and make no new holes.
 
Thanks greg !!!

As a matter of design I;m a little confused why a dump would be place back into the carb with a gasket block to control it. But no matter I just would like to get back running.

Is this the gasket your talking about?

Much thanks!! !!!!!!



100_7574.jpg
 
That's the gasket!

As far as your concerns on the dip bucket cleaning go, a good soak like it sez to do on the can followed by a hot water rinse is the only way to get all traces of the chem dip removed. It will not harm anything if you follow instructions, and not leave it in too long. While it is not water based, it does have some emulsifying agents in the mix to facilitate a good rinse with warm or hot water. Tough jobs sometimes need a couple of dips. Trevor is spot on, nothing else works though a soapy rinse sometimes helps get the slimy stuff off followed by a clear rinse. I then use a small high intensity light, (mini mag for instance), and spray brake clean to shoot through all passages to make sure they are at least passable. The chem dip will not remove the white death, the white zinc or aluminum corrosion. You have to physically remove that with small orifice brushes or soft copper wire. You might have to do that only after all "proper" gaskets, assembly, and tuning still won't get it to run right; or go with another carb. Only assemble the carburetor when you are sure it is absolutely dry.
 
You probably won't encounter this lawrence, but just for future reference, if there ever comes a time that you legitimately do need to modify a metering gasket by adding a hole or holes, purchase an inexpensive leather hole punch kit from whorebur fake tulz or the like. Lay the correct original gasket in place over the new gasket, select the appropriate size punch and give it whack. Makes a uniform round hole, rather than a jagged mess.
 
Thanks trever


yes my sheet punch did not work. But if I was to buy an actual punch perhaps it would be better to just buy a new gasket for the same cost. But in those extreme mods your right.

So I finished all my work, reassembled the carb put it back on the motor. The engine started over immediately . The engine idles as required. So much struggle to get to here.

Although its still idles a bit high. I think I will try to lower the primary fuel float level. I think that's the problem. I can get some idle down when I manually pull up the gas pedal with my foot a tinny amount but I'm sure I can tune this out.

My real questions is this. I have a gauge on the vacuum. I can crank the idle screws on the meter block each side till the cows come home. I cant get any movement on the gauge . It stays at 22 psi. It will flux when I rev the engine a small amount of psi but,,,

so before anybody yells at me the parts and passageways are clear! I did not change the small cork gasket on the end of the screws. But I think this is bigger that that.

Any ideas?

Warmly
lawrence
 
Super, good work if the only problem now is high idle. The screws on the metering block sides are for air, you turn them out to lean the idle mix.

Could be air leaks. Cap off all auxillary vacuum connections such as for the distributor. Look for manifold leaks.

At the high idle setting on the high idle cam, the throttle plates should have about a .025" clearance to the bore for starters.

The accelerator pump lever arm should have .015" clearance with the actuator arm at wot.

Look for any tensions, jams, tightness, or binding however slight in the throttle linkage to the carburetor, on the carburetor, and kickdown linkage. Is there a dashpot?

when I manually pull up the gas pedal with my foot a tinny amount
Click to expand...

Well, there you go!
 
You're getting closer lawrence. Double check the vacuum gauge you are using. Most vac gauges I've seen for automotive tuning measure vacuum in hg, not psi. Those are two totally different standards of measure, although there is a conversion between the two. That said, 22 psi of vacuum would be somewhere north of 50 hg...an impossible figure to reach. So, 22 hg of manifold vacuum at idle if that is correct would be excellent. The vacuum needle should sharply drop off to small numbers when the throttle is blipped wide open and then quickly return back to the peak idle number as the engine returns to idle speed.
 
Hi trever


yes your right on the increment measured. Its in mmh/g says the gauge. I'm using a brake line bleeder gun.

The enclosed you tube is dark but my caption on you tube gives more info. You can hear the engine also. I'm frustrated. I think this might be the carb problem again?

post carb rebuild loping engine - youtube

Url=http://youtu.be/ziaybupo-vq

warmly
lawrence
 
Last edited:
Hi lawrence. Yeah its still the carb like its always been. You can't maintain a steady vacuum, so you can't idle, and you can't idle because you can't hold a steady vacuum. There must still be a leak somewhere, but since you haven't found it externally, then it has to be internal. The mixture screws on the metering block mainly affect the a/f mixture at a steady idle speed. Because your engine speed is fluctuating well above idle, the air/fuel mix is being influenced by the transition circuit. That is likely why you're not seeing any change in behavior no matter where you set the mixture screws. I'm sure that's not what you want to hear, but I don't really know what else to tell you.
 
Hi guys

well more news on my tinkering. I have found two issues. One is that when working I noticed my hand making an impact on the rpm rate slightly. So I got out the aerosol can of starter fluid and sprayed the outside of the carb and heat riser, sure enough a strong rise in rpm.

Man I just changed the riser and throttle body gaskets. So obviously a vacuum leak which is giving me my rough idle.

Q.1 is there a hot rodders trick? I thought of getting some kind of silicone spray or rubber spray. Try and "seal" some areas in part. Wait 24 hours to dry. Run the engine and see if I can notice a change. "seal" another side/seam wait 24 hours to dry .... Repeat.....

Try to narrow down the area of leak. Am I right in assuming its not the blue re-usable bowl gaskets other wise apparent leaks?



When I get the engine running and running high rpm holding the chock plate closed. I can see with my fuel gauge I get 3-4 psi hooked to the line to the fuel tank. That's low for my carter at 6psi max. This keeps my clear inline 3 dollar filter low and frankly empty. But it runs?

When I put the fuel line down into a two gallon can below the engine and run from there. I get a steady 5.75---6.25 psi at low idle er um 2000 rpm by ear

if I open the choke plate and lower the rpm I dip to 3-5 psi at the gauge (fuel from the can.) the needle bounces with rough running engine.

Second question : under high or low rpms should I worry . Would the need for pressure from the pump need to be constant? Is the fluctuation an problem. When this happens I'm from the can and the in line filter is a constant about 3/4 full and wavy.

Any views are appreciated.

Warmly
lawrence
 
Perhaps there is some warpage either in the carb throttle plate or the top of the intake preventing adequate seal. A warped throttle plate seems most likely. It can happen from over torquing the securing bolts. Any goop that you tried to smear on would be a half-assed bandaid at best. It would have to be impervious to fuel and extreme heat. I can't see anything like that lasting very long, plus it would look hideous. Best would be to examine the two mating surfaces with a true straight edge to determine if they are both perfectly flat.
Running with the choke plate closed just further confirms that too much air is being sucked into the intake from places where it shouldn't be getting sucked in. If there were no leaks, and the engine were at operating temperature, closing the choke plate would kill the engine instantly for lack of air, but its still running, meaning it is getting plenty of air even with the plate closed.
 
Thank you trever

for responding. Well I tried to reproduce your advise. I guess I was wrong in my last e-mail. If at high loping idle I close the choke plate all the way down flat closed . The engine will run down and stall.

I lopes so hard that I cant be sure I have a vacuum leak somewhere when I try to spray carb cleaner or starting fluid.


When idling high I do pull the vacuum hose off the metering block which goes to the distributor. I put my finger over the valve nipple and feel a small amount of suction. The engine will run down and stall.

I'm at my wits end. Short of my next idea to buy a bottle of carb cleaner and put it under the engine and pull directly from the bottle. Its combustible right.

I think at my wits end right now that the carb is just not clean somewhere. What are your thoughts.

I guess I need to tow the car out to a mechanic.

Lawence
 
Yeah lawrence, my opinion that the issue is contained in, on or directly around your carb is not wavering. I'd be willing to bet your next paycheck that if you did nothing other than swap a dead nuts 200% guaranteed dialed to the gnats ass carb on you engine, you would realize instant and dramatic improvement. That isn't to say that your current carb is junk, but something sure as hell isn't right. I'm sorry you're having such ongoing issues with it. I agree that you should probably seek professional assistance before the frustration drives you insane.
 
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