MTFCA Forum

Along with everything else, (clearly I should have picked a T in better shape) I think the generator is bad and so is the magneto. The other day I turned the lights on and the Amps Gauge dropped as it should, but no amount of revving brought it back to ‘0’. I also tried running the engine on magneto and it quickly died. I thought for sure it ran on it before. Did they just go bad one day? I haven’t ran a test on it yet, though.

It's as likely that your generator cutout is bad, or the wiring, as the generator itself. As for the magneto, The same is true as far as wiring, and there could also be a problem at the magneto post. Since it at least appeared to run on both magneto and battery recently, as I recall, I'd check the wiring and perhaps the ignition switch. First of all, I'd fully charge the battery, then look the wiring over. It should not be necessary to rev the engine beyond a fast idle to tell if the generator or magneto is working.

Could be a number of things. First unless you have the 3rd brush set up to 6-8 amps your generator probably won’t go to 0 with bright lights on. If lights are off does it show a positive amperage? If so it’s probably ok just not set high enough. Magneto not working- could be as simple as a bad contact in the switch or lent on the point of the magneto post. Address those things first before further steps. I’m sure others will have better solutions. Best John

JTT3 wrote: ↑

Sun Jun 12, 2022 9:54 pm

Could be a number of things. First unless you have the 3rd brush set up to 6-8 amps your generator probably won’t go to 0 with bright lights on. If lights are off does it show a positive amperage? If so it’s probably ok just not set high enough. Magneto not working- could be as simple as a bad contact in the switch or lent on the point of the magneto post. Address those things first before further steps. I’m sure others will have better solutions. Best John

As I’m thinking about it, it never shows a charge, but the battery always cranks the starter easy.

The ammeter may be bad or hooked up backward. If the battery is staying charged, it suggests that the generator is working, more or less, assuming you've started the car a good number of times without charging the battery. Failing to run on magneto could easily be a switch or wiring issue, or a problem at the mag post contact.

Make up a test bulb rig using a headlight socket and an 1156 bulb. One lead to mag post. One lead to ground. The bulb should light just by cranking the motor over. It should glow brightly at idle. And glow brilliantly at at very fast idle, to a point where the bulb burns out.
I just lived this nightmare....
https://mtfca.com/phpBB3/viewtopic.php?t=29441

Notice the ammeter needle location @ rest. Start it up, vary the rpms. Does the needle move? If so The generator does. If it moves negative with higher rpms, the ammeter is wired back wards. Check generator output @ the gen terminal with an analog volt meter. You should read voltage running. If not gen is dead. If so run a wire from the gen output terminal to ground to potentially keep it from damaging itself further.

Hopefully you haven't changed anything with the wiring. If you accidently hook a hot wire from the generator to the magneto post, you will ground the generator and at the same time de-magnetize the magneto. It could also be a problem with the ignition switch. One side goes to the ammeter and the other side goes to the magneto. When you turn on the key to the left it should connect to the battery, and if you turn it to the right it would connect to the magneto. If somehow you have it wired wrong, or if there is a problem with the switch, it could accidentally connect the battery to the magneto.
So check it all out carefully.
Norm

Norman Kling wrote: ↑

Mon Jun 13, 2022 1:02 am

Hopefully you haven't changed anything with the wiring. If you accidently hook a hot wire from the generator to the magneto post, you will ground the generator and at the same time de-magnetize the magneto. It could also be a problem with the ignition switch. One side goes to the ammeter and the other side goes to the magneto. When you turn on the key to the left it should connect to the battery, and if you turn it to the right it would connect to the magneto. If somehow you have it wired wrong, or if there is a problem with the switch, it could accidentally connect the battery to the magneto.
So check it all out carefully.
Norm

Fortunately I haven't messed with any of the wiring except at the timer earlier.

I imagine that the generator is still charging as the car still starts every time. Maybe the ammeter has gone bad. Come to think of it I never see the needle move unless I turn the lights on. These are just a couple problems that just cropped up.....I guess.

CatGuy wrote: ↑

Mon Jun 13, 2022 8:22 am

I imagine that the generator is still charging as the car still starts every time. Maybe the ammeter has gone bad. Come to think of it I never see the needle move unless I turn the lights on. These are just a couple problems that just cropped up.....I guess.

2 false assumptions.
You still REALLY NEED to have someone look your T over.

speedytinc wrote: ↑

Mon Jun 13, 2022 8:46 am

CatGuy wrote: ↑

Mon Jun 13, 2022 8:22 am

I imagine that the generator is still charging as the car still starts every time. Maybe the ammeter has gone bad. Come to think of it I never see the needle move unless I turn the lights on. These are just a couple problems that just cropped up.....I guess.

2 false assumptions.
You still REALLY NEED to have someone look your T over.

I know.....I can't get anyone.....I've emailed one Iowa Club and either the guy died or he's ignoring me? I may put an add out to actually 'hire' someone to come buy. Maybe I need to actually join a club first? Frustrating.

The car is wired incorrectly? Just a guess, but it supports the stated facts.
The battery still starts the engine, but never any charge indication at the dash ammeter.
There are total of five wires in the charge and discharge circuits of the Model T. But these five wires are commonly miss-wired causing these exact circumstances.
There are two simple tests you can easily conduct that will tell you if all five of these wires are correctly terminated.
Attached is a CORRECT copy of wiring for all Model T electrical circuits. There are many WRONG Model T Car wiring diagrams floating around and this diagram is one of only two that I will only use.
Print out these diagrams and give me a call later today and I will coach you through the two simple tests to ensure your wiring is correct.
Ron Patterson
231-448-5085

Ron Patterson wrote: ↑

Mon Jun 13, 2022 9:48 am

The car is wired incorrectly? Just a guess, but it supports the stated facts.
The battery still starts the engine, but never any charge indication at the dash ammeter.
There are total of five wires in the charge and discharge circuits of the Model T. But these five wires are commonly miss-wired causing these exact circumstances.
There are two simple tests you can easily conduct that will tell you if all five of these wires are correctly terminated.
Attached is a CORRECT copy of wiring for all Model T electrical circuits. There are many WRONG Model T Car wiring diagrams floating around and this diagram is one of only two that I will only use.
Print out these diagrams and give me a call later today and I will coach you through the two simple tests to ensure your wiring is correct.
Ron Patterson
231-448-5085

Thanks, Ron. I printed it off, but not sure when I'll get to it this week. Looks like a busy week and really hot out in the garage!

CatGuy wrote: ↑

Mon Jun 13, 2022 10:00 am

Ron Patterson wrote: ↑

Mon Jun 13, 2022 9:48 am

The car is wired incorrectly? Just a guess, but it supports the stated facts.
The battery still starts the engine, but never any charge indication at the dash ammeter.
There are total of five wires in the charge and discharge circuits of the Model T. But these five wires are commonly miss-wired causing these exact circumstances.
There are two simple tests you can easily conduct that will tell you if all five of these wires are correctly terminated.
Attached is a CORRECT copy of wiring for all Model T electrical circuits. There are many WRONG Model T Car wiring diagrams floating around and this diagram is one of only two that I will only use.
Print out these diagrams and give me a call later today and I will coach you through the two simple tests to ensure your wiring is correct.
Ron Patterson
231-448-5085

Thanks, Ron. I printed it off, but not sure when I'll get to it this week. Looks like a busy week and really hot out in the garage!

Scott,

The very best advice I can give you, is to take Ron Patterson up on his offer to help you out. You WILL get to the cause of your generator trouble if you follow through with him.

Ron Patterson is one of the most knowledgeable persons in the club concerning the electrical system. He can guide you through. I would also suggest that you buy the book published by the club "Electrical System" It has step by step instructions on how the wiring is done and how the magneto and generator systems work.
I would suspect that the generator field is not holding enough residual magnetism to cause it to overcome the resistance in the cutout. But that is only a guess. The cutout could be bad or might be reverse polarity from the battery. The battery on a T is intended to have a negative ground and the positive goes toward the starter switch. The cutout for a Model A looks the same as a cutout for a Model T, however the battery polarity on an A is positive ground, so if you have the wrong cutoff it could be the problem.
Concerning the club, you should join the closest chapter to your home, even if it is quite a few miles away. it is very possible they have members near you. You will get a membership roster which will give you many possible contacts who will be happy to help you or recommend someone locally who can. i would come, myself, if you lived in San Diego County, but you live too far.
Norm

Ron has a new wiring diagram. It looks fantastic. I will have to print a copy when I can get a color printer available.
Thank you Bob Cascisa.

Ron helped me with my coils and my generator. He knows his stuff. He is retired so it would not hurt if you called him
now and asked if it is OK to call him again when the weather cools off.

CatGuy wrote: ↑

Mon Jun 13, 2022 9:03 am

speedytinc wrote: ↑

Mon Jun 13, 2022 8:46 am

CatGuy wrote: ↑

Mon Jun 13, 2022 8:22 am

I imagine that the generator is still charging as the car still starts every time. Maybe the ammeter has gone bad. Come to think of it I never see the needle move unless I turn the lights on. These are just a couple problems that just cropped up.....I guess.

2 false assumptions.
You still REALLY NEED to have someone look your T over.

I know.....I can't get anyone.....I've emailed one Iowa Club and either the guy died or he's ignoring me? I may put an add out to actually 'hire' someone to come buy. Maybe I need to actually join a club first? Frustrating.

In case you're not aware, there are 2 major Model T clubs, MTFCA, (which this forum is associated with), and MTFCI. In case you've only been looking for MTFCA chapters, here are some MTFCI ones...
Looks like the MTFCA chapter in Des Moines is pretty close to you. I guess that's the one you've been trying to reach?

Heart Of Iowa Ts
c/o John Wilson
6901 SW 15th Street
DES MOINES IA 50315-5436

Ron. What are the two simple checks to find out if the five wires are connected correctly.

Thanks Jim

Jim
Print out the "Wiring Diagram"PDF above and with it in hand give me a call later today and I will explain.
I should take the time to write it down in electronic format for future use?
Ron Patterson
231-348.5085
.

Ron,
Which one of the diagrams do I use? The ‘5041E’ or the ‘5042’?