Holley 4180 - won't idle........

[clintonvillian]

Fellas what's your thoughts:

Brought the new bronco home. It ran fine, for 2-3 days, started just fine. No pumping the pedal nothing.

Hit the key, it started, and idled.

Well, took it for a drive last night and when I got back shut it off. 30 mins later went to start it, and it wouldn't... Hit the pedal and it sputtered. Cranked it over again and pumped the pedal and it took off.

Once it starts I have to keep my foot in it, or it just dies. Driving down the road, if I let off of the gas to change gears, it dies.

I am think maybe I need to adjust the idle, but I am hesitant due to the fact it started so dang easily when I brought it home...

 

[SHX669]

What type of fuel pump do you have - mechanical or electric if electric where is it mounted.
Do you have two fuel tanks - if so did you switch tanks? Are you trusting a fuel gage ? - is there enough fuel in that tank?

 

[clintonvillian]

What type of fuel pump do you have - mechanical or electric if electric where is it mounted.
Do you have two fuel tanks - if so did you switch tanks? Are you trusting a fuel gage ? - is there enough fuel in that tank?

Mechanical

One tank

I put 5 gallons in it this morning.....how much do you have to keep in it?

 

[1970 Palmer]

Like most issues, we have no idea. So you are going to need to diagnose the problem one item at a time.

Make sure the secondary's are not hung open which will result in a large vacuum leak. It's easy to check, so get it out of the way.

Check your float levels, just pull each site plug one at a time and take a look at your float level. A stuck float will dump excess fuel into your engine with the same symptoms. Adjust the float level if necessary.

Do you have any adjustment on your idle mixture screws? A leaking power valve will eliminate the sensitivity of the adjuster screws.

Do you have any major vacuum leaks?

Do you have a vacuum advance distributor? I do not see a ported vacuum hose connected.

John

 

[SHX669]

Along the vacuum leak train of thought - check for a vaccum cap on the carb that has cracked or fallen off .

 

[spap]

I would do a through cleaning too,Who knows what’s in the fuel bowl
Clean and rebuild

 

[jckkys]

That Holley is filthy. Start by getting a rebuild kit, dissemble it, clean it out, and rebuild it.
Ford had Holley make the idle mixture hard to adjust. The idle mixture screws are hidden under plugs on all 4 corners. If you remove the plugs, the idle mixture can be adjusted on all 4 throttle bores with an allen wrench. The thread pitch is the same as Autolite/Motorcraft 2100, 2150, and 4100 carbs. So idle adjustment screws for Ford 2100 can be transplanted to the Holley.The location is the same too. The '79 4180s had 2100 type idle adjustment screws with knurled heads, from the factory.
The accelerator pump circuit is the same as other 4150/4160 4bbls and tuned the same way. The power valves on 4180s are the 2 stage type but work like other Holleys. They are good carbs, with annular discharge booster venturis.
After a good cleaning and a rebuild kit it should run well. If not, we can diagnose any problem then.

 

[clintonvillian]

Thanks for all the input.

One thing I noticed yesterday messing with it, the blade is open as shown in the picture. after working the throttle some it snapped shut, almost like it was hanging open. Any chance this is the problem? It is hanging open when I get out of the throttle and getting way too much air and killing the motor?

I am going to buy a rebuild kit.....I found a NOS motorcraft kit on ebay, my initial thought was get it, but if it has been setting for awhile, what are the chances some of the gaskets have started to dryrot?

 

[1970 Palmer]

The NOS gaskets in the old kit are not going to dry-rot. The cork gaskets might be shrunk depending on how it was stored. They can be easy resized if they are shrunk. Thirty seconds with a large faced ball peen hammer on a hard surface will stretch them back out without any damage. Just like in doing metalwork, the operator is the important end of the hammer.

 

[DirtDonk]

One thing I noticed yesterday messing with it, the blade is open as shown in the picture. after working the throttle some it snapped shut, almost like it was hanging open.

Your description sounds like normal choke function. It's only open like in the pic when it's warm. Then, as the spring contracts it tries to close again, but is limited from doing so by the throttle linkage interlocks.
Once you manipulate the throttle it allows the choke plate to spring closed.
All normal.

In fact that's what you're doing every morning when you "set the choke" by pushing on the throttle once for cold starts.
That action serves two purposes. One is to set the choke to it's cold/closed position, and the other is to let the accelerator pump squirt some fresh raw fuel into the bore/venturi to help it start.

Any chance this is the problem? It is hanging open when I get out of the throttle and getting way too much air and killing the motor?

A misadjusted choke can certainly cause all sorts of problems. But if just being open can cause the engine to die, you have other issues to deal with. It's normal warm/hot running position is supposed to be wide open.
It's only closed, to partially closed when the engine is cold then warming up. It gradually opens up to it's full-open point usually within a few minutes of driving.

Paul

 

[1970 Palmer]

That Holley is filthy. Start by getting a rebuild kit, dissemble it, clean it out, and rebuild it.
Ford had Holley make the idle mixture hard to adjust. The idle mixture screws are hidden under plugs on all 4 corners. If you remove the plugs, the idle mixture can be adjusted on all 4 throttle bores with an allen wrench. The thread pitch is the same as Autolite/Motorcraft 2100, 2150, and 4100 carbs. So idle adjustment screws for Ford 2100 can be transplanted to the Holley.The location is the same too. The '79 4180s had 2100 type idle adjustment screws with knurled heads, from the factory.
The accelerator pump circuit is the same as other 4150/4160 4bbls and tuned the same way. The power valves on 4180s are the 2 stage type but work like other Holleys. They are good carbs, with annular discharge booster venturis.
After a good cleaning and a rebuild kit it should run well. If not, we can diagnose any problem then.

Jckkys, you must be a young guy, LOL. Seriously, that carb model is newer than any of my Holley experience which ended about 1971-72.

So I'm curious. In the OP photo, what is the cast diaphragm in front of the choke housing. I'm guessing a load governor, or some kind of a emission limiter? I've seen some weird stuff on the old Super Duty Hadley Auto Transport trucks that came through our shop.

With diesels so common today, it's hard to image how many large trucks were gas powered "with Holley's" back in the day.

 

[jckkys]

The diaphragm pulls the choke open. In other words it's a choke pull off like the 1970-1974 2100s had behind their choke chimneys. Every carb maker tried to open their automatic choke faster for emissions compliance. Only some 4180s had that diaphragm. The rest relied on the piston inside the coke housing. Ford's 2150s had diaphragms hanging out behind the carb for the same purpose. I use both electric choke heating and exhaust manifold heat stoves to heat my choke's bi-metal coil spring. As a retired teamster I learned how to best use manual chokes. My wife doesn't like them tho.
The OP needs to know that automatic chokes have stepped fast idle cams. The accelerator needs to be opened a little to set the choke. He also needs to remove the plugs over the idle mixture screws to adjust the mixture.
Heavy truck carburetors are a little weird. They have governors, odd throttle linkages, and odd choke systems. I only use them for parts.

 

[clintonvillian]

So what exactly should the start procedure be?

Push the pedal down partly to set the choke, and fire it up?


It is odd that it ran so well, and then had this issue. Then I turn around and went out 2-3 days later, hit the key and it fired right up, no issues....

I am just a little hesitant to tear into because I am afraid I'll make it worse, or not be able to get it tuned back.

 

[DirtDonk]

So what exactly should the start procedure be? Push the pedal down partly to set the choke, and fire it up?

Yep, that's it in a nutshell. But as we like to say, when it comes to carbureted engines, or those using a points type ignition, Your Results May Vary...
Some people can go out to their vehicle on even the coldest day of the year and fire it right up without the choke setting procedure. While others have to set it, then pump the pedal one, two, or even three more times to squirt still more fuel into the throat of the carb.

Everyone with an old vehicle just has to try different ways to see what works, what does not work, and what (if anything) works best.

But you nailed the basic instructions with your question.

It is odd that it ran so well, and then had this issue. Then I turn around and went out 2-3 days later, hit the key and it fired right up, no issues....

Well, unfortunately my personal feeling is that it's not odd at all. Instead it's just the nature of the beast and how these things seem to work sometimes.
Yes, you should have more consistency. But that seemed to get fewer and farther between the older these vehicles get.
And yes, when you fix something it should stay fixed a lot longer than it does. But it doesn't... Always that is.

I am just a little hesitant to tear into because I am afraid I'll make it worse, or not be able to get it tuned back.

This is very a good attitude! Unfortunate you have to think that way, but true enough. But I'll cut that in half. While you might make something worse by messing with it, it's an extreme rarity that you can't get it back to where it was. With a little knowledge about what you are doing, ALMOST EVERYTHING can be returned to working order.
Or better than ever working order.

It's not a science (even though it is) in the real world applications. It's still more of voodooblackmagic sometimes.
Or at least it seems that way a lot!

Paul

 

[jckkys]

There are idle feed restrictions in the metering block that are only a few thousands in diameter and as any small orifice, it can be plugged up by a tiny piece of crap from the gasket for instance. The idle mixture screw is also in a tiny hole. That Holley is about 35 yrs. old. I would think it's been rebuilt a few times. It's likely time for another rebuild. There are plenty of used and rebuildable specimens on ebey cheap. Here's a good example;https://www.ebay.com/itm/1986-87-Fo...134306&hash=item3da77a1b8a:g:sowAAOSwz-Be-88X. In short you can't screw up something that's irreplaceable.

 

[SHX669]

So what exactly should the start procedure be?

Push the pedal down partly to set the choke, and fire it up?


It is odd that it ran so well, and then had this issue. Then I turn around and went out 2-3 days later, hit the key and it fired right up, no issues....

I am just a little hesitant to tear into because I am afraid I'll make it worse, or not be able to get it tuned back.

Both of mine start by pumping the pedal twice, take foot off of pedal , hit the key and they start .
A few years ago They used to start with one pump but I think this "new gas " evaporates out of carb more than the gas we used to have .

 

[clintonvillian]

Well guys, it is running fine now, I got the ne WH M1A1 stainless tank in and all lines ran. I think it was sucking some air when the fuel got low.

I'm going to give it a good cleaning once I put it away for winter. Until this if its not broke don't fix it.

 

[clintonvillian]

Okay I lied....

Started it up idled fine for 30 mins...

Took it down the road and dies pulling into the driveway. Still won't idle. If I barely and I mean barely leave my toe on the pedal it idles fine.

Problem is I can't find an idle speed adjustment screw in this mother .....

 

[jckkys]

If slightly depressing the accelerator peddle makes it idle well just increase the curb idle speed until you get the quality of idle you want.

 

[jckkys]

Here's a photo; https://img.wonderhowto.com/img/04/...just-curb-idle-speed-holley-carb.1280x600.jpg.