Runs rough on battery

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Wotherj
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Runs rough on battery

Post by Wotherj » Fri Sep 11, 2020 6:08 pm

Hi everyone,
I’m sure this has been asked heaps of times before, but I’m stumped. I’ve got a couple of issues and I’m sure they are connected.
The car’s a 1924 Touring set up to run on coils and fitted with a solenoid (not that this should matter, but it’s the only non original item). The coils all test okay on a HCCT.
Problem 1: when I try to start the car using the starter motor, I can’t hear the coils buzzing whilst it’s turning over. It’s not struggling to spin over, just can’t see or hear the coils. Naturally the car doesn’t start.
When it’s not turning over but the key is still on, the coils work. When I crank the car by hand, everything works as it should. The car starts right up.

Problem 2: with car running on battery it has an intermittent miss, when driving and under load the car coughs and splutters. Switch the car over to Mag and it runs beautifully.

Any help is appreciated in diagnosing this issue.
Cheers,
James.


Peter, Memphis TN
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Re: Runs rough on battery

Post by Peter, Memphis TN » Fri Sep 11, 2020 7:07 pm

Both those issues suggest the same problem. It's a faulty electrical connection somewhere in the system.

If the starter cranks the engine properly, and will do so for several seconds, then it may not be in the connections between the battery, the starter switch, and the starter, nor in the ground circuit from the battery to the engine.

If the coils buzz correctly when the starter's not being used, that would normally indicate a good set of connections in that circuit.

BUT when you do both together, one of two things is happening. Either the enormous load the starter puts on the system (by far the biggest load of all) is causing some connection to go faulty, or it's drawing the battery's output down to below the point needed to actuate the coils.

In order to figure it out, I will suggest some simple tests. But first, I will suggest that the "solenoid" you mentioned is in the starter circuit, is a very likely location for a bad connection.

First test: With the ignition off, crank the engine with the starter for 10 seconds. Then, immediately feel every connection in the starter circuit. Start with the battery, and feel every connection, all the way to the starter. Don't forget the strap or cable from the negative post of the battery to the frame. It's also a good idea to slide your hand over the entire length of every cable. If any connection, or any location in a cable, is HOT, you've found a bad connection. Mostly, taking the connection loose, cleaning and lightly sanding the connector, and tightening everything back up, will fix that connection.

The second test involves using a voltmeter. A simple, cheap, multimeter will do. Using the DC Volts scale, measure the voltage at the battery posts (not the clamps or cables, but directly on the posts). Then, hit the starter switch, and note what happens to the battery's output. At rest, the battery should measure 6.3 volts, although your meter might not be able to get that accurate, which is not a problem. What's important, is that under the cranking load, what does the battery voltage fall to? If it falls below 5 volts, you may have a battery problem. If I were to experience that, I'd hand-crank the car, motor over to the local AutoZone or similar, and ask them to do a load test on the battery, which they do for free. Of course, if they find a weak battery, they'll want you to buy a new one from them, but they're usually OK.

By the way, your problem #2, sputtering when running on BATT, is also indicative of a bad connection somewhere.

If neither of my tests shows any kind of fault, then look at the wiring in the coil circuit. Start at the input side of the solenoid, where the little wire connects, and then to the terminal block on the engine side of the dash, and then to the ignition switch, and then to the bottom connection on the coil box. Simply check that every connection is clean and firm.

If none of this solves your problem, the only thing left is the connections inside the coil box. On your car, like mine, they're hard to get to and see, and you might have to dismount the box in order to get to them.

Best of luck, and let us know what you find.

Peter


John kuehn
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Re: Runs rough on battery

Post by John kuehn » Fri Sep 11, 2020 7:39 pm

It’s an electrical issue somewhere in the system. First thing to do is to check the switch. Turn the key back and forth several times or jiggle the key in the switch. Do the simple checks first. Do the headlights burn? If not it start at the battery cables. If they are original get you some new ones. Check the ground connection and go from there.
But do check the switch. The starter will turn the engine but if the coils don’t buzz it won’t start.
Good luck.

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GrandpaFord
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Re: Runs rough on battery

Post by GrandpaFord » Fri Sep 11, 2020 9:21 pm

John and Peter have the right advice. I can only add the suggestion, after cleaning a contact, to use an electrical contact grease, available at Lowes or from McMaster Carr. The grease will keep the connection from re-oxidizing and becoming resistive again. You can also use the grease available from automotive parts stores that is used on battery terminals.


Topic author
Wotherj
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Re: Runs rough on battery

Post by Wotherj » Mon Sep 14, 2020 6:34 am

Hi everyone,
Well it appears that there were two issues.
Despite the battery having just been recharged, it wasn’t up to the job. Sitting idle it measured 6.4 volts, under load it dropped to 3.7 volts. So I went out and bought a new battery.
I installed the new battery, it spun over a lot quicker, but there still wasn’t any spark coming from the coil box. I pulled the switch panel and hot wired it. When I spun the car over with the starter motor, you could hear the coils buzzing away. So the issue was with the switch. I pulled it apart but couldn’t find any noticeable reason for why it failed. Thankfully I had another switch so I installed that. It now runs perfectly,

Thanks everyone for all your help and tips.

Cheers,
James.


John kuehn
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Re: Runs rough on battery

Post by John kuehn » Mon Sep 14, 2020 8:43 am

That’s good news that your problem was in the switch. They can be contrary with making contact internally. There are several posts about cleaning them up and sometimes bending the contacts just a bit will get you going.
Good luck and glad you got it fixed.

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john in kzoo
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Re: Runs rough on battery

Post by john in kzoo » Tue Sep 15, 2020 7:52 am

I have sort of the same problem. (No buzz when on battery runs great on mag, I even start it on mag when it's warmed up). However if I tap the face plate of the switch or jiggle the key I can make them buzz. I have checked all the connections and have crimped the contacts a bit to try to assure contact with the inner contact lever. Still finicky....
Thought I would try and replace the inner contact lever as I'm sure the existing one is well worn after 105 years....thoughts????
I'ts driving me nuts trying to figure it out

Thanks in advance.....John


John kuehn
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Re: Runs rough on battery

Post by John kuehn » Tue Sep 15, 2020 8:00 pm

John
Going by your profile you have a 15 Touring. Go to Snyder’s website and check closely at the switch for your 15. There is a close up of the switch which may help. They do make a new switch for a 15 but it’s not cheap. Don’t know if they make replacement parts for the switch’s that’s are mounted on the coil box but replacement parts are available for the later in dash switch’s 19 and up. Maybe yours needs more tweaking but after 105 years of twisting and turning something has to wear.
Good luck!

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john in kzoo
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Re: Runs rough on battery

Post by john in kzoo » Wed Sep 16, 2020 7:30 am

Thanks John, I deal a lot with Lang's. They have the most of the internals for my switch. Just wondering if others had the same issue (when on battery either tap the face plate or jiggle the handle to get the coils to buzz), and if by replacing the inner contact lever if the problem went away?

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Fordwright
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Re: Runs rough on battery

Post by Fordwright » Wed Sep 16, 2020 3:35 pm

The battery voltage is lower than the magneto voltage. If there is resistance in the circuit, there may not be enough current to make the points buzz.

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john in kzoo
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Re: Runs rough on battery

Post by john in kzoo » Thu Sep 17, 2020 8:26 am

They buzz if the key or face plate are tapped, so I'm not sure it's a voltage issue. I only use the battery to start the car when it's cold.

Anyone had this experience? Would replacing the inner contact lever address the issue? thoughts.....

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Fordwright
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Re: Runs rough on battery

Post by Fordwright » Thu Sep 17, 2020 9:47 am

john in kzoo wrote:
Thu Sep 17, 2020 8:26 am
They buzz if the key or face plate are tapped, so I'm not sure it's a voltage issue. I only use the battery to start the car when it's cold.

Anyone had this experience? Would replacing the inner contact lever address the issue? thoughts.....
Try doubling the battery voltage. You won't burn anything out because the magneto goes up to 30 volts.

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