41 flathead just cuts out when running 😕

[hombres ruin]

Hi guys.. this is a headache. Some background . 41 flathead coupe stock distributor and one of skips coils, napa IH 200 condenser, new 6 V battery, rebuilt Holley 94 has some leaks around the base but I will replace the carb. Manifold brake vacuum. New grounding strap new battery strap from fire wall to battery, new negative strap to solenoid, new glass bowl fuel pump and fuel filters and fuel line. I rebuilt the carb with a kit from ken Ct . It went fine it does leak around the throttle rivet which ken said is indictive a sloppy shaft. So I am replacing the carb. The car starts and runs nice , idles fine. Fuel pump pumps fuel but twice the car has been running in the garage then dead stop. No sputtering to a stop just cuts out. First time it was a loose ignition wire under the dash. It happened again and I pulled the spark plug and it had spark. The ignition wire is tight all the connection to that wire were checked and cleaned. Happens again today cut out. I have fuel delivery into the carb and there is no sputter or slowing down before it cuts out. Seems electrical to me. Any ideas ? It wouldn't start up after it shut down

[fordwife]

A faulty ingition switch could cause an intermittant problem like this. try running a jumper wire from the battery to the coil and see what happens.

[Phil Gillespie]

If it stops dead without any fuel supply run down which normally causes spluttering then its surely pointing to electrical side.
had this happen to me whilst driving and it just stopped dead. Found wire had come off on coil connection.
Phil Nz

[Ken/Alabama]

If you put a jumper from the battery to the coil you will burn it up. Put the jumper across the back of the ignition switch.

[JSeery]

Or battery to ignition side of the ballast resistor.

[Deucekoop]

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I had the same problem, mine was the connection from the distributor to the coil

[hombres ruin]

So I went through it all today , so there is no spark coming from the plug, I have 6 volts at the coil and ignition wire , condensor is putting out as well. The connection of the ignition wire to coil is fine,I think I can rule out ignition switch,coil(new skip rebuild) and condenser as it's a IH 200 from napa. I narrowed it down to distributor I am not getting anything to the plugs , the rotor looks worn down and the points may be bad. So I pulled the distributor and will send it to bubba to be rebuilt. I will keep you guys posted

[Ken/Alabama]

6 volts at the coil could be a problem. If your not going through a resistor the coil could be toast.

[JSeery]

Mifht explain the burnt points as well.

[tony starr]

Are you bypassing the ballast resistor?

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[hombres ruin]

I will be the first to admit I am not good with electrical .. now I went out and followed the ignition wire and it goes into the resistor under the dash. The resistor looks in good working order nothing is burnt or blackend . What volts should I get at the point where the wire attaches to the coil?

[drolston]

The ballast resistor is in series with the ignition coil primary windings. If the ignition voltage is on but the points are open, no current flows, so there is no voltage drop across the resistor, and you will see a full 6 volts at the coil. With the points closed, current flows and there will be a voltage drop across the resistor, and lower voltage at the coil.

[hombres ruin]

drolston.. that's right with ignition on I get 6 at the coil with its cranked I get a drop to 4 volts . So can I rule out the resistor as the problem?

[Drbrown]

?? Clarification re original post .... if its a crab, the NAPA IH 200 is the ballast resistor and the condenser should be a NAPA FA54 (found in very recent Bubba post).

[hombres ruin]

Drbrown.. original post said "stock distributor " which is a helmet style not crab

[drolston]

Originally Posted by hombres ruin

drolston.. that's right with ignition on I get 6 at the coil with its cranked I get a drop to 4 volts . So can I rule out the resistor as the problem?

That sounds good, but the current draw of cranking the engine can drop the battery voltage quite a bit, depending on the condition of the battery. When you crank the engine and voltage at the coil drops to 4 volts, what does voltage at the battery terminal read. If near 6 volts the ballast resistor function is confirmed.

The other way to test it is to bump the starter and watch the voltmeter hooked to the coil. When you catch it with the points open, you will see 6 volts, and with the points closed, around 4 volts.

[hombres ruin]

So here I am at first base again with this problem . I had the distributor rebuilt by bubba, new coil from skip and a new Stromberg 97 from uncle max. New fuel line from pump to carb. New IH 200 condenser as recommend by skip. Everything went on well with no problems. We primed the carb and the engine started right up , run very smooth and sounded great. The engine stayed on long enough to set the idle , we reved it up and bought it down to the set idle many times and got it humming. Then it cut out again !! Wouldn't re start. We have fuel pressure that's been tested. No obstruction in the lines . Took the spark plugs out on both sides and no spark!! Everything was tested with a volt meter and was fine. How does it run so Well then just cut out and have no spark?? I don't understand what is happening . Any help would be great!

[grumppyoldman]

I had the same problem, Take the ballast resistor out and clean all the connections, studs wire connectors and reinstall. My problem went away after doing this. Al

[drolston]

If, when it is not producing a spark at the plugs, you are still getting voltage (4 or 6 volts) at the coil with a rebuilt distributor (meaning points properly set, rotor, cap and condenser good) that leaves two things, - the coil, or the high tension ignition cable from the coil to the distributor. Bad ignition cables generally cause missing or cross fire, or won't start when wet, but not sudden death. I had a coil that would not start after it got hot, but it never just died. Maybe you have the touchiest coil ever. I would replace it and the coil to distributor cable and try again. Even if the coil is not the problem, you should always carry a spare.

[tony starr]

That new negative cable you mentioned in your original post, is that suitable for 6 volt? I'd start with another condenser as a cheap test and checking all wires and connections are good and clean. Something is obviously failing once things warm up.

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