Coil.?..

[RustBucket]

I've run Pertronix for the last 10 years. It's worked quite well. One day it started missing and coughing at higher RPM. I checked gas stuff like you are doing and it all seemed okay. My hunch, though was the Pertronix. I changed it out and voila, no more missing.
Rustbucket

[Gregs672000]

So if the plugs are black, it isn't a lean issue (carbs not getting fuel), so it's not very likely that anything is plugged. It is either getting too much fuel or not burning what you have. Find your pump and determine what it is. Most, like the popular 42S, are set for 3-4lbs, but some are higher at 7-9lbs, and that COULD be enough to overwhelm your needle and seat in the carbs (google search the brand and numbers on the pump. You should be able to find what its PSI is). If that happens, the float chamber will overfill and cause problems with the emulsion tubes, but would also likely be dripping lots of fuel from the accelerator jets and down the carb throat.

HOWEVER, I am highly suspect of this at this point based on your description and recent success. I think you have a timing or ignition problem that involves the Petronix. Get that timing light, it may tell you what's what.

[Linda]

Those fuel hoses could be cracked and sucking air under the clamps. I would replace.
Also wondering about the pressure the pump is putting out, too much or too little....
Linda

[redroadster68]

but the car has run 5 yrs or more with that pump...so it wouldn't (shouldn't change the psi suddenly ) maybe???? what would make the timing suddenly go out of wack? I can check the issue last time...was exactly the same...never touched the timing.

[redroadster68]

thanks Linda and greg I will investigate further. yes Linda those fuel hoses looking old. amazing what ya find up there in the neither regions of a 52 yr old gem....perhaps a family from Yonkers???? I just like the word Yonkers.
they were dry which was great. the moisture in the pic was from me spaying parts cleaner on it to see an ID

[Gregs672000]

Ya, very unlikely that the pump has changed pressures. The petronix could be failing, causing the timing to not advance or to be sporadic. As I suggested earlier, you messed with the wires to the ignition just by replacing the coil... perhaps you reconnected a weak or damaged wire that is continuing to give you problems. I do not see how you could have a lean fuel condition with black plugs... the engine is telling you otherwise, so a leak or fuel line plug just seems very unlikely to me. Keep messing!

[redroadster68]

Thanks Greg. All suggestions much appreciated.

[redroadster]

This is were the oscilloscope/ Sun machine is needed
You watch the volts , point break , choke it
to see what happens to high voltage spike
Did you look at the wires coil at night in the dark to check for arcing ? I found some puzzling probs that way ....hands behind your back ...use a long screwdriver to touch it. 1 plug fouled can loose you big power at low revs

[redroadster68]

thanks...other Redroadster. I have new coil wire and spark plug wires on order....ZAP!!!!!

[JT68]

Heres a few simple suggestions:

To test the fuel system, do as David suggested first and check for a tank full of trash.

If the tank looks very clean, take the gas line loose at the carbs, rig up 6' of extra fuel line and route that to a 5gallon bucket.

Turn on the pump and watch it fill the bucket, if it peters out, stops flowing part way through, you do have a delivery issue, if it fills the bucket quickly and steadily, you don't. (unless your cornflakes need to be stirred while driving) A good electric pump can fill a five gallon bucket fairly quickly.

Goes without saying you need to be careful. ONLY do this outside and make sure not to allow any sparks/static etc.


If it passes both those tests, but still craps out driving, add a fuel T near the carbs and route a line to a MECHANICAL fuel pressure gauge. Place the gauge somewhere you can see it while you drive. Outside the windshield is fine, just so you can view it while things act up. If the fuel pressure takes a big dip (like from 4psi to 1) when the car starts misbehaving, you have a fuel delivery problem. You could do this test first, but since gas tank trash and line issues are such common problems, I would do all the above before buying (or borrowing) a FP gauge.


Ignition system:

As noted in the suggestions above, like anything electronic, the Pertronix units can act up, and they can do so intermittently, but many seem to last a very long time. Fairly random I think. If so, the problem may be temp or vibration related or just a poor electrical connection-coil primary wires etc or ignition system voltage wimping out (poor connection again)

Coils rarely fail and even more rarely intermittently. Chances are it wasn't the coil, especially since the problem returned with the new coil-the probability of both coils failing in the identical intermittent fashion are probably ridiculously low. Same with the ignition resistor if you have one.

Depending on what coil you are using, I would either swap the Pertronix unit out for testing or just temporarily put in a points distributor for testing. If the Pertronix is having a bad day, the odds of a points distributor creating the same problem are almost zero.

Lastly, if we find it wasn't the pertronix or the coil and the problem is still there, its likely one of the coil primary connections, the coil-to-cap plug wire or the ignition switch is flaking out with vibration. Rare but certainly possible. Coil primary wire connection and fuel problems are much more common.


Lastly Carbs:

if we find steady, clean fuel delivery and the ignition definitely never, ever misses a spark and it does the same thing with two completely different distributors, we are left with carb issues..

There are lots of places internally where solexes can have problems..lots of little orifices' and passages that are very susceptible to clogs and can do so intermittently. They can also overflow intermittently especially if you are running too much fuel pressure. You many need a pressure regulator depending, but rule out everything else first.

If these are fresh type 3 or 4 carbs, I would lay odds that it is one of the many potential problems listed above, not the solexes, but if any trash (ever) ran through the carbs, all bets are off.

If these are early carbs type 2 carbs and they have not been rebuilt properly and fairly recently..it it much more likely the carbs are involved.

If the carbs have never been professionally rebuilt, that could be your problem as well.

If it was me, I would verify the fuel delivery, then make sure the coil/resistor wiring is perfect and swap the distributor to something totally different. (points, Eastcoast, 123 whatever). If it STILL does the same thing, then I would verify steady +voltage to the coil or resistor ALL the time when running. Very last test would be to swap the solexes.

Test one thing at a time, methodically, don't swap 5 things at once!

Hope this helps, Feel free to ask further questions to clarify. Good Luck, stay warm! jt

[redroadster68]

Thank you for all the troubleshooting tips. I will methodically work my way through each system, one component/ theory at a time. Yikes . Thanks again JT for your input and parts enroute. Ya I’ll try and stay warm. Hopefully not wth a gas fire in my garage lol just kidding

P.S. thanks D. Premo also

[redroadster68]

So last night I opened up carbs, took floats out , put them in a bowl of water....no bubbles and they both floated perfectly. Checked the float valves and both open and close freely and effectively. Inside of carbs spotless. I turned on fuel pump and measured the volume / rate of flow at the carbs. Filled bucket up steady and without Hesitation. Gas clean. Filter clear.
I’m leaning towards Iggy,, but I will continue my stressful journey “ this is fun, this is fun, this is fun, this is fun, this is fun, this is fun, ...

[redroadster68]

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6A5AE968-B2B0-43FB-A03B-24B22D5095A9.jpeg

Removed cover, checked out floats, float valves. All good nothing binding,