Ok so working on my 1920 touring, trying to get it to run on Mag did a little you tube search and forum reading. I did the 1156 bulb test had good results light got brighter, had 10v but wouldn't run on mag bought a new switch installed it it ran on mag briefly then died, now trying the bulb test it doesn't get brighter. I also pulled the mag post and it was clean .Do the magnets need recharged? If so I've seen some videos of the battery charger "tap" I am assuming they are using 6 volts when they do that. Any thoughts or suggestions. Thanks
I can think of two reasons for a weak mag. 1 Weak magnets. 2 excessive crankshaft end play allows too big a gap between mag coils and magnets.
The best charge is to individual magnets, one at a time, off the flywheel. But you can do an in-car charge that will give you about 60% of a full charge. Google MTFCA: magnet charge.
The end play thing is less likely, and requires engine work to fix. See Paragraph 992 on Page 234 in the Service Manual.
If it runs on battery that doesn't mean it will run on mag, even if the mag is good. With a good mag it depends on if the coils are set up properly or not.
If in the process of installing the new switch, you inadvertently connected the battery to the magneto, it would de-magnetize the magnets. You should get up to 30 volts AC across the light bulb at higher speeds. End play in the crankshaft could be your problem or de-magnetization.
First thing to check is end play. If minimum end play, then you could try an in the car magnetization.
I know I didn't wire it incorrectly, I am going to try to charge the mag in car see if that helps. What does it run to have coils rebuilt? I inherited this car from my dad and know he has other coils that I could send off as cores or to be rebuilt. The car runs good on battery, I just want to make it run on mag if I can without tearing the motor apart
Both these guys do great work. Check with them on prices.
407 Stonegate Drive
THE COIL DOCTOR
6498 Flaxton Court
Coils set up to run on battery don't always work on mag. I had a car with a bad mag and adjusted the coils to run very nicely on battery. When I rebuilt the mag and tied to use the coils the car ran very poorly on mag even though it had a new coil ring, recharged magnets and proper clearance. I took the coils out and readjusted them and the car ran fine on mag but just so so on battery.
Before trying an in car recharge lets find out definitively the nature of your magneto problem.
The in car recharge is only a last ditch effort and not the first thing you try with magneto trouble.
Your description of the magneto readings given in your first post above are ambiguous.
Give me a call and I will be glad to help you diagnose the trouble to be sure we are chasing the right problem.
Today, we successfully diagnosed and corrected Don Staples generator not charging problem and he has a new rebuilt generator working properly with a FunProjects Voltage Regulator.
Seriously, start with the easy stuff first. I changed the band linings this week. I was extremely careful about removing everything to get the hogsheads off. I made a concerted effort to keep close track of all tools near the open transmission. I used zip ties and dental floss and stuffed the transmission with rags when it came time to install the band washers and nuts. I also spent the better part of two days applying Ultra Black to seal everything up. When it came time to fire her up, she started on battery and immediately died when I switched over to mag. Me heart sunk because I was sure I'd somehow damaged he coil ring closing her up as she ran great on mag before the band change. I'd almost resigned myself to pulling the engine for a rebuild and missing the most of the driving season coming up. The next day was spent reading every mag related post I could find, and decided to follow other's advice and eliminating simple solutions first. Turns out, my mag pickup post was clean, but was grounding internally. I cut a couple rubber gaskets to isolate the post from he housing and tried again. She now runs on mag as well before the band change. Now I only have to spend $30 on a new mag pickup and not a few hundred on a rewound coil ring and all the lost driving time from an engine rebuild.
Here's an update on the Mag situation. I got back to working on my touring tonight. I put the old switch back in the car and tested the magneto again I could get over 20 volts no problem, but it would not run on Mag. I installed the new switch again and this time the magneto was putting out power, I switched over to mag and look at that it ran. I am confused as to what happened I am positive I wired it correctly as I have a wiring diagram, but am excited that it runs on mag. I appreciate all of the input from you guys.