Truck stumble, coil voltage issue?

[Zax63]

My 223 has been idling fine, but stumbling pretty bad when I give it gas. I'm pretty confident it is not fuel related, but a low spark voltage situation. Yesterday I measured the voltage at the coil while idling and it was around 2.2 volts. I'm pretty sure that is a problem. What should I be seeing on the coil at idle? What are the common causes of low ignition system voltage on a 223? The coil, condenser, cap, rotor, points, plugs, plug wires are all pretty new.

[slick4x4]

Stumble , when you give it the pedal
Is very possible the accelerator pump not working
I have a truck like that... runs fine ... give it gas & it wants to die a bit

Does yours start without choking it ?
If not... I would check the accelerator pump...
Very easy to do
Without it running....
Look down carb
Push the throttle wide open
You should see some gas squirting down the throat

[Zax63]

Stumble , when you give it the pedal
Is very possible the accelerator pump not working
I have a truck like that... runs fine ... give it gas & it wants to die a bit

Does yours start without choking it ?
If not... I would check the accelerator pump...
Very easy to do
Without it running....
Look down carb
Push the throttle wide open
You should see some gas squirting down the throat

This is the 3rd carb on the truck since i've had it. It is one of the new ones from Ebay. The stumble has been present with all 3 carbs. It doesn't act like it wants to die. It's more of a severe misfire when under load.

[Zax63]

Just did a quick test. On my coil bracket there is a piece that the hot wire goes into and out to the + on the coil, I believe it is called a ballast resistor. But if I bypass it and check the voltage at the coil it's 12.4 volts. I started it up like that and it will take throttle now with no stumble. So i'm guessing the ballast resistor is bad?

[unibody madness]

Not positive but think you will burn thru points that way. Its not for everyone But a pertronix will replace your points, run and start smoother and will work with 12v just fine. make sure you have the part number on your actual distributor because there are two that will be listed depending on the year, they will not both fit. I use them on both my 223 and Yblock 292 with no issues

[ThinLizzy13]

Like unibody madness said, you will burn up your points if you bypass the resistor wire. You could get a new wire or bypass it and put a resistor block on the bypass wire. I did that with one of my trucks so I didn’t have to fiddle around with a resistor wire anymore. I think I used a ballast resistor for a *ahem* brand x type vehicle. Or switch in electronic and be done with it.

[Zax63]

Yeah, the bypass was just for testing i'm not going to leave it like that. But one thing i'm confused on still is I keep reading that the early 60's f100s used a resistor wire and not a ballast resistor to reduce coil voltage. If that is true, why do I have a ballast resistor in the first place?

[slick4x4]

Because somebody put it there ...
Not Ford

[redstone65]

I think voltage to the coil should be around 7 volts if I remember correctly.

+1 for electronic ignition. It’s the way to go if you can swing it. No more pitted points to booger with.

[charliemccraney]

Maybe a previous owner didn't know it used a resistor wire and installed the resistor, thinking it was missing, effectively doubling up on the resistance.