Help getting a 1912 to run on battery

Marshall V. Daut · Post by **Marshall V. Daut** » Mon Jan 21, 2019 4:03 pm

I am helping a friend get his recently restored 1912 Model T running, but we've run into a problem. And it's just the opposite of what I read everyday here in regards to problems starting on "Mag". I have never had any luck with the search function on this website, as it hangs up interminably. And I don't see any threads posted recently that address our problem. So I am turning to the electrical system gurus here for assistance.
First, a little background on what's going on: This car has a rebuilt 1915 engine with starter, operated by a modern battery and remote solenoid. It is not wired into the ignition, which is fired by a motorcycle battery grounded to the frame. The starter is in one wiring system, the ignition in another. So, there is no crossover for potential masking of symptoms. My friend built this car and has done many T's before, but this one has a been a pain. It starts on the "Mag" side of the ignition switch every time and idles beautifully. But flip the ignition switch over to "Batt" and it dies - every time. He has checked continuity of the ground, the hot wire from the motorcycle battery to the coil box terminal, and the switch contacts behind the plate. All good. The switch is new, but we swapped that out anyway. No change. A complete known-operating wooden coil box was swapped with the one on the firewall with the same results: from "Mag" to "Batt", the engine dies. Clearly it is not getting power. The coils do not buzz on "Batt", either, which of course explains why the engine won't run on "Batt". I have relocated the motorcycle battery ground wire in an effort to get a better ground and eliminate that as a suspect. No change. The little motorcycle battery is good, too.
I am stumped. Usually it's the magneto that causes the problems when switching the key from "Batt" to "Mag". Our problem is just the exact opposite. What am I missing? Where else should I check? It MUST be something simple I am overlooking.
Thanks in advance.
Marshall

pdgriesse · Post by **pdgriesse** » Mon Jan 21, 2019 4:19 pm

Don`t have a wiring diagram handy but---That "hot" wire has to go to the Ignition. switch which is then connected to the coil box---from your description, appears the Ignition switch is not in the circuit....(on the battery side)

Post by **DanTreace** » Mon Jan 21, 2019 4:32 pm

Since no current to the coils.

1. The coil box mounted switch is wired incorrect or wires are shorted.

2. The battery used for ignition is dead, or its not wired to the battery standoff on the coil box, or the negative terminal of that battery isn't on a ground path to the frame/motor for the timer.

Scott_Conger · Post by **Scott_Conger** » Mon Jan 21, 2019 6:12 pm

Well, I just lost the self-control battle with myself, so will ask Why On Earth Are There 2 Batteries???

And now I am going to suggest that the small battery is actually dead. Just because it shows voltage on a volt meter does not mean it will supply voltage/current when there is a completed circuit with resistance in it.

Marshall V. Daut · Post by **Marshall V. Daut** » Mon Jan 21, 2019 7:02 pm

Thank you for the responses so far. Let me address the advice as best I can.
(1) Two wooden coil boxes were tried, one from a running car where both "Mag" and "Batt" operations functioned via the switch. Both switches check out o.k. Same problem: the engine starts and runs on "Mag", but dies immediately and completely (no sputtering) when switched over to "Batt". I think we can probably eliminate a short in the wooden coil box or defective switch from the list of suspects.
(2) The "hot" wire from the motorcycle battery is connected to the post on the firewall, as indicated in all the wiring schematics. No breaks in the wire. The ground wire was re-located, but no change. Motorcycle battery is supposedly new.
(3) I have no idea why my friend set up the car with two separate batteries, one for ignition, one for the starter. I was brought in after the car was built and after problem could not be diagnosed by the owner. The rat's nest of wires to and from the remote starter solenoid and from the motorcycle battery disturbed an electricity-challenged dunce like myself to no end. I am of the "simpler is better" school when comes to wiring. The more ad hoc wires in the mix, the more likely a problem will rear its ugly head. However, I am stuck with this car's electrical design; but I should still be able to get the darned thing to run on battery. It can't be THAT difficult! Something simple is undoubtedly causing this problem.
(4) Do I understand Scott correctly that the motorcycle battery COULD be dead or defective and the continuity readings taken will still register good? Doesn't the source of the power need to be good, meaning the motorcycle battery, in order to get these readings? Otherwise, only wires are being tested for shorts or breaks by taking these readings. However, if continuity readings can be taken - even though the battery is bad - that is throwing us off the trail. I will call my friend and recommend he try a different motor motorcycle battery.
Please keep those suggestions coming! I will definitely post the solution and the correct suggestion made to reach it.
Marshall

Post by **DanTreace** » Mon Jan 21, 2019 7:50 pm

Yes and yes. A motorcycle battery can be so weak it will not throw enough current to fire coils.

Helped a fellow with similar set up on his ‘15 speedster. Told him so after trying so after lunch we got a new battery and she cranked right up!

pdgriesse · Post by **pdgriesse** » Mon Jan 21, 2019 8:13 pm

The ignition switch selection (Mag or Batt_) decides from where to send the voltage, to the coil box. Disconnect that battery from the coil box and reconnect it to the Ignition switch. ONE wire--Ignition switch to coil box--is all that's required. The way you are currently wired you are sending Mag and Batt, voltage to the coils in the MAG position. (not good as you can demagnetize the magnets if the engine is not running and the switch in the MAG position is ON) It sounds like your Ignition switch and batteries are Ok. Just connect the Battery to your switch and disconnect the coil box battery connection. Good luck!!

pdgriesse · Post by **pdgriesse** » Mon Jan 21, 2019 8:22 pm

Just to clarify--I called it the "coil box " wire---you called it the Firewall post----SAME THING---you should only have one wire connected there--from the ignition switch. Connect your battery lead to the ignition switch.....

Scott_Conger · Post by **Scott_Conger** » Mon Jan 21, 2019 9:47 pm

Paul

reread his post...it sounds like "ignition switch" is the coil box switch...remember he has a wood coil box and exchanged it with another wood coil box. Those boxes have two posts (mag/bat) and proper leads go there. Perhaps there isn't even a battery connected to the box (since the box switch routes either mag or bat to the coils this may be the case). I think you're giving advice for someone with a dash mounted switch and a barrier strip on the firewall?

In any event, imagine a non-starter car that is now fitted with a starter, a starter solenoid, and a "rat's nest of wire". I walk away from those jobs, as experience has taught me that even after sorting out problems with vehicles like this and sorting them out, the owner invariably starts dinking around with it afterwards and usually to no good end.

Marshall

you're a trooper for taking this on. Good luck.

Post by **Steve Jelf** » Mon Jan 21, 2019 11:53 pm

I'm an electrical dummy. When guys start talking about how many foonads of impudence it takes to induce the fremulator I get an advanced case of MEGO. But I think the ignition system on a pre-starter Model T is so simple that even I have a basic understanding of how it's supposed to work.

As the drawing shows, the coil box has a top row of four terminals for the timer wires. Below that is a row of four terminals for the spark plug wires. And below that are two terminals for your choice of power sources. The terminal near the "driver's side" end of the box should have only a wire from the mag post attached to it, as the picture shows. If any other wire is attached there, get rid of it. Near the "passenger side" end of the box is the battery terminal. Mr. Ford likes to pretend that you don't need a battery, and that's what the picture shows, but we know better. You want a known good battery that produces six volts. If your battery happens to be eight or twelve volts, that's OK. One wire goes from the negative post of the battery to the frame. Be sure the metal-to-metal connection is clean and tight so you have a good ground. Another wire goes from the positive post of the battery to the battery terminal on the coil box. Again, if there's any other wire connected here, get rid of it, at least for now. So now you have two wires bringing current to the coil box, one from the magneto and the other from the battery. That brings us to the switch.

We'll use Dan's picture for this. It shows how the switch chooses the source of power for the coils. Turning it clockwise makes a contact between the wire from the MAG post to the wire in the center going to the coils. Turning the switch counter clockwise connects the (red) wire from the BAT post to the center wire going to the coils. So current is coming from either the MAG or the BAT and is going into the coils. It passes through the coils to that top row of terminals and is carried by the red, green, blue, and black wires to the timer. The timer is just another on-off switch. As the roller, rotor, flapper, or brush rotates it makes contact with each of the four wires, grounding each in its turn to complete the circuit and causing the corresponding coil to fire a charge to its designated spark plug.

The coils don't care where the current is coming from. They should fire whether the juice is coming from the mag or the battery. Since the car runs on MAG, we know that current is flowing from the post to the terminal, through the switch and the coils, and through the timer to ground. But the car dies when switched to BAT. So the circuit is broken somewhere before it gets to the coils. Your choices are: bad battery; bad ground at the battery or frame; broken, loose, or disconnected wire between the battery and the BAT terminal on the coil box; broken or disconnected wire between the BAT terminal and the switch; switch not making contact.

I can't think of any other reasons that current from the battery isn't reaching the coils.

Post by **TWrenn** » Tue Jan 22, 2019 8:17 am

He has checked continuity of the ground, the hot wire from the motorcycle battery to the coil box terminal, and the switch contacts behind the plate. All good.

Okay...I had a similar problem a while back with my stock '12 touring. Here's the emberrasing discovery I found
with the help of a friend who is smarter than me. Long story short...even though, like you, I showed good continuity of the hot wire from batt to switch, coil box contacts, etc. I still had no buzz on battery. Guess what...turns out the friggin FUSE was just "good enough" to show continuity, yet "bad enough" to not provide enough voltage. I put in a new fuse, and VOILA! problem solved immediately! Took me longer to get the red-flush out of my emberrased face than it did to change the fuse and solve the problem. So, just try what I did, and hopefully you will have the same results, IF that is you have an in-line fuse in your hot wire.

Post by **Charlie B in N.J.** » Tue Jan 22, 2019 8:40 am

You've described a straight circuit from the battery to the coil box in one of your posts. If this is the case you have a defective motorcycle battery that goes "open" when a load is applied. If it's as I read it the batts N.G. Put a test light on the batt post on the coil box & check for power. By the way the second battery is kind of nuts and unnecessary.

fliverfan · Post by **fliverfan** » Tue Jan 22, 2019 10:02 am

Ten post coil box?
If the starter battery is known good, just disconnect the cycle battery and run a 12 gauge wire from the + post of the starter battery (or hot side of the solenoid) to the coil box. If the engine still quits the problem lies between the bat coil box terminal and the coils.

Marshall V. Daut · Post by **Marshall V. Daut** » Tue Jan 22, 2019 10:14 am

I called my friend last night and recommended (based on advice here) he try a different motorcycle battery. He said he taken two batteries to a local auto parts store to have them checked, and they were o.k. I thought he had told me the motorcycle battery was new. Apparently not. So, the battery is now suspect in my opinion. I also suggested running a hot wire from the 6 volt battery for the starter to the battery post on the firewall and see if the coils buzzed. I see that "fliverfan" has suggested the same thing today.
I guess we need to wait until the friend follows both suggestions with the motorcycle and 6 volt batteries before moving to the next level of diagnosis. But I just can't see what else could be hindering the ignition system from operating on "Batt" if all these things check out o.k. It's almost got to be the battery.
Marshall

Post by **Mark Gregush** » Tue Jan 22, 2019 10:48 am

Get rid of the motorcycle battery and just run the lead from the hot side of the solenoid to the to the terminal on the coil box. The solenoid is just replacing the foot starter switch. Would be no different then millions of other T''s. You don't say if the motorcycle batter is 12 volts or not, but if the car runs strong on magneto, you are just using the battery side of the switch for starting anyway. While maybe not as fast off the line, any T I have driven will still get up to 35+ running 6 volts.

Rich Bingham · Post by **Rich Bingham** » Tue Jan 22, 2019 11:04 am

The model T is meant to run on "mag". With an adequately functional magneto system, they start readily enough on "mag". It's often overlooked that the owner's manual recommended starting on "mag" for cars with self-starter. Essentially, "bat" is for hand cranking a cold or balky engine when you can't quite get enough "oomph" for good voltage out of the magneto.

Post by **Steve Jelf** » Tue Jan 22, 2019 11:51 am

If the battery for the starter has enough guts to turn the motor, it sure has plenty for the coils. As Mark says, use it to fire the coils. If that doesn't work there's an interruption in the circuit at one of the places I listed.

Marshall V. Daut · Post by **Marshall V. Daut** » Tue Jan 22, 2019 3:30 pm

Until I hear back from my friend about the battery condition and whether he was successful tying into the 6 volt starter battery to check for buzzing coils, I have been thinking about how to check the ignition switch itself on the wooden coil box. We have tried two coil boxes, meaning two different switches. The engine died both times when switching from "Mag" to "Batt". The chances that both switches are bad are not high. But now my friend says he THINKS the second one ran on battery, whereas yesterday he was sure it had. O.K. An old suspect revisited. In my eyes, both switches are again suspect. We removed the front plates of both switches and found everything o.k. inside = clean, no broken wires, good brass contact tension.
Since this is not the later switch, where wires behind the dash can be swapped between "Mag" and "Batt", a different method for checking the "Batt" side of the these switches needs to be tried. Do you see anything wrong with the following? Since the engine starts and runs fine when the switch is set on "Mag", we therefore know that side of the switch works. If we disconnect the "hot" wire from either battery running to the battery post on the firewall and connect the wire from the magneto post here, I should think by then turning the switch to "Batt" (which is now running off the mag) that this will tell us immediately if the "Batt" switch side of the switch is good. If the engine starts, it's good. All we have done is switch the "Batt" and "Mag" sides of the switch. If, however, the engine still won't fire, the switch(es) must be bad. Since no power source is being used, there is no danger of demagnetizing the magneto. Am I correct in thinking this is a good test of the switch? I sure don't want to have to add re-charging the magneto to the list problems to correct on this car!
Marshall

Scott_Conger · Post by **Scott_Conger** » Tue Jan 22, 2019 5:07 pm

I am asking myself why you don't place an ohmeter from the Bat post on coil box to the coil box's bottom copper strip and look for continuity when on "BAT" and then place ohmeter on mag post on coil box and to the coil box's bottom copper strip and look for continuity when on "MAG". I'm not getting the drama of two batteries, swapping wires, swapping posts, etc. That mag ring is going to eventually get a battery connected to it and when that happens the car won't run on Mag, either.

Post by **Steve Jelf** » Tue Jan 22, 2019 10:02 pm

I would test the switch as Scott says. But if you don't have a meter, then yes, you can run the mag current into the BAT side of the switch to see if it works. Just be sure there's no way for battery current to reach the mag.

Post by **gcomo** » Wed Jan 23, 2019 6:22 am

Grab a test light and start at the battery working you way to the coil box.

Marshall V. Daut · Post by **Marshall V. Daut** » Wed Jan 23, 2019 10:24 am

So that you all aren't sitting on pins and needles waiting for the next chapter of this saga to unfold - and you ARE waiting breathlessly, aren't you? - my friend's knee replacement went south on him yesterday, so he won't be working on his car for a few days at least. Plus, we are snowed in, but good, with more coming in the next day or two. I can't see getting across the river to his place until at least Friday or over the weekend.
I will report back when there is something significant to relate. In the meantime, thanks for all the suggestions. I will follow them all.
Marshall

Post by **DanTreace** » Wed Jan 23, 2019 11:23 am

Marshall

OK, we'll wait

If you can get out in that snow, a easy tool for simple wiring and switch of the Model T is an $8.00 illuminated continuity tester. Found at any auto parts store.

Best thing for switch work, has built in low voltage battery, and bulb. Lights up when circuit is completed.

On this switch, testing the key for 'BAT' and 'MAG' positions, to be sure the key works the contacts.

The clamp lead is on the COIL terminal, from the switch that would go to the common strip on the base of the coil box, where power would be, depending if from the magneto, or from the storage battery.

The tester pointed tip is now contacting the BAT terminal, and the tester lamp is illuminated when the key is turned to BAT position.
Then switched the key to MAG position , no light....that is good. No leakage and contact is good. Then placed the pointed tip to the MAG terminal and tester lamp lit again, as the key was still in MAG position, so that is good. Turned key to off, and tester lamp went off, so simple test of key switch is made with a test light.

Post by **TBill** » Fri Jan 25, 2019 6:47 am

Hi Marshall,

Saw your name and had to post this OT reply. Work is progressing well on the 1926 Fordor I bought from you a couple of years ago. Should be “like new” when complete and I plan to show it and drive it.

I hit a small snag maybe you can help me with ... The driver’s side sheet metal “pillar” (between the door and cowl) is rusted out at the bottom and I’m having to replace it. I’ve had some response on this forum but no follow ups. Any suggestion would be most appreciated.

Sorry I haven’t kept up. Take care.

Bill

Marshall V. Daut · Post by **Marshall V. Daut** » Sat Jan 26, 2019 1:35 pm

O.K. Mystery solved. Before reading the following answer to our problem, let me summarize the situation. I had responded to my friend's request for help when he said this newly-restored 1912 wouldn't run on "Mag". After troubleshooting for a while using the standard mag testing procedures, it turned out that the engine WAS running on "Mag" all along. My friend had told me incorrectly that when he switched from "Batt" to "Mag", the engine died immediately. I finally discovered when it was my turn to switch the key that he was mixed up. It was just the opposite: the engine started and ran on "Mag" where the ignition switch had been initially set, but died when switched to "Batt". My fault for not verifying that first. O.K. Not too much time wasted checking the mag post for lint and tracing wires. Good practice for a faulty magneto operation in the future. This mag was fine.
Now to see why the engine wouldn't run on "Batt". The first ignition switch actually checked out o.k. with his continuity tester, but my friend suggested we swap coil boxes with one that he knew had a working ignition switch. The coil boxes were swapped. Well, the engine still wouldn't run on "Batt", even with the switch that was known to be good. That left ground wires and the motorcycle battery as the only remaining suspects. I relocated the ground wire to a freshly scraped part of the frame and anchored it down, thinking perhaps a bad ground through the thickly painted frame was causing the problem. Nope. Same symptoms. I then questioned my friend about the motorcycle battery (which I should have done in the first place). He has used them for years to start his many Model T's and always took them to a local auto parts store to have them checked beforehand. This battery was supposed to be good, yet we couldn't even get the coils to buzz, let alone start and run the engine.
I had to leave for the day with the problem unresolved. I still suspected the allegedly good motorcycle battery, but decided to see if the guys here could supply other possibilities. Good troubleshooting suggestions came forth. That night, I called my friend and suggested he run a hot wire from the 6 volt modern battery he was using to run the starter to the battery terminal on the firewall. Bad weather and a bad knee replacement problem intervened, so he was unable to perform this simple test until this morning. He just called and guess what!?! With a hot wire coming from the major battery, the coils buzzed! It had been the supposedly "good" motorcycle battery that was causing the problem all along. Hurray! Simple solutions are always preferred around here.

A lesson about old Fords re-learned: it's usually something simple at fault. Not always (to be read: "broken crankshaft, disintegrated rear end thrust washers, exploded magneto magnets), but usually so.
Thanks again to all of you for your most helpful suggestions. I just wish it had occurred to me the first time to by-pass the motorcycle battery and use the main battery. Then none of this would have been necessary. Next time when my friend calls with a similar problem, I'll check the battery FIRST!!!
Marshall

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