83 ranger carburated high idle

[83DangerRanger]

My truck has a high idle. I feel even when cold the cold start seems real high. Then after a min it will drop down but still be idling high. Its carburated.

I also noticed the idle adjustment screw isnt even touching the carb.

Could my cold start be adjusted wrong?

 

[rusty ol ranger]

Does it continue to idle high even after its warm?

Im leaning toward a vaccuum leak, prolly a carb base gasket.

 

[Uncle Gump]

RPM readings would be good...

But if the idle screw isn't touching the stop... something isn't right. Bound up... bent up... buggered up... or possibly something on the choke side. Fast idle cam stuck... linkage wrong etc...

I think a vacuum leak on a carb engine would be too lean to idle high... probably lucky if it would idle at all.

 

[rusty ol ranger]

RPM readings would be good...

But if the idle screw isn't touching the stop... something isn't right. Bound up... bent up... buggered up... or possibly something on the choke side. Fast idle cam stuck... linkage wrong etc...

I think a vacuum leak on a carb engine would be too lean to idle high... probably lucky if it would idle at all.

Nah ive had it happen quite a few times. Granted that was all on large V8s.

What engine are we dealing with here? 2.0 2.3 2.8??

 

[83DangerRanger]

Its a 2.3 4 cylinder. I the cold start was way to high when I first bought it. I got the cold start operating pretty dang good. But once warm I'd say its probably idling around 1000rpm maybe 1100. Just needs to come down a little.

I also notice the idle screw next to the cold start screw is backed out all the way and isnt even touching the seat

 

[rusty ol ranger]

The idle screw is prolly backed all the way off in order to get it to idle as low as possible.

All the idle (speed) screw does is hold the throttle plate open a little bit when the acclerator is fully released.

So...

1- You got a sticky throttle. Try to (gently) push the throttle closed by hand. Ive seen return springs get weak and cause this.

2- You have a vacuum leak somewhere allowing extra air in somewhere besides the carb.

Is that the little YFA Carter 1bbl similar to what they used on the 300 inline 6? If it is grab the main body of the carb and see if its loose. Theres 4 screws that hold the main body to the baseplate and they love to come loose.

 

[83DangerRanger]

The idle screw is prolly backed all the way off in order to get it to idle as low as possible.

All the idle (speed) screw does is hold the throttle plate open a little bit when the acclerator is fully released.

So...

1- You got a sticky throttle. Try to (gently) push the throttle closed by hand. Ive seen return springs get weak and cause this.

2- You have a vacuum leak somewhere allowing extra air in somewhere besides the carb.

Is that the little YFA Carter 1bbl similar to what they used on the 300 inline 6? If it is grab the main body of the carb and see if its loose. Theres 4 screws that hold the main body to the baseplate and they love to come loose.

That's a photo on my carb. I gave it a good shake and its doesnt wobble for say but I can see it move a little.

The throttle is closed.

I notice to when running seems like Its running too rich from the smell.


Sorry for the long reply. I apologize and appreciate all the help

 

[rusty ol ranger]

View attachment 28646

That's a photo on my carb. I gave it a good shake and its doesnt wobble for say but I can see it move a little.

The throttle is closed.

I notice to when running seems like Its running too rich from the smell.


Sorry for the long reply. I apologize and appreciate all the help

It shouldnt move at all.

You see those 4 little screws down where it bolts to the flange that bolts on the intake? Pull the carb and tighten/locktite those screws and try it,

I doubt its rich if its idleing high.

After you get the screws tightened and the carb bolted back on (with new gaskets), look up the idle MIX setting. Most carbs are 1.5 turns out from lightly seated. But check on yours for sure.

 

[RonD]

RPMs are controlled by Air Flow

If you add more fuel to any engine you get a Flooded Engine, not higher RPMs
If you add more air you get higher RPMs , the point of the throttle plate, "more air, go faster, lol"

So you have an air leak, for sure

With engine idling unplug any vacuum line you can see and plug that port with your finger see if RPMs drop, if so that hose has a leak somewhere

Test PCV Valve hose first then Power brake booster if so equipped

 

[83DangerRanger]

I will get the 4 bolts tight. Which carb do I have anyone know?

I also noticed some airlines broken see photos its 2 line both going to the computer area

The one end has a boot but nothing to plug into.

I also noticed the damper on the air intake is open when cold. I have not started the motor yet today

 

[83DangerRanger]

As for the carb bolts I can see one. I can feel a second across from the one but that's it. I dont see or feel 4. You sure this carb bolts down with 4 bolts

And it just has a smell when it's running kinda burns your nose. I relate it to too much feel in my day. Maybe it's just oil.

 

[83DangerRanger]

I'd also add I cant believe how much vacuum and bs is under this hood. I have a 86 toyota Dolphin (motorhome) that engine bay is easy as 123 lol.

 

[RonD]

Plug any open vacuum hoses
Pull off and plug any others, one at a time, to see if idle drops

Yes emissions laws changed over the years for different types of vehicles, most of the vacuum hoses are for emissions systems

I think you have a C-1 YFA Carb

The Cold air duct is used to help engine warm up faster and shouldn't cause running issues or the high idle, it is there to pull in pre-heated air from around exhaust manifold until engine warms up.
In very cold climates its good to have working, i.e. lots of days with below freezing temps

 

[83DangerRanger]

Do I need to worry about the two lines I found? I'm not sure what those two do

 

[RonD]

Not at this point, just see if they have vacuum present with engine running, if so plug them

To track down what each vacuum line is for you will need to track all the ones that ARE hooked up then whats left are what those hoses are for.