Starts on batt.. dies when turned to mag...

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Model T Ford Forum: Forum 2016: Starts on batt.. dies when turned to mag...
Top of pagePrevious messageNext messageBottom of page Link to this message  By duane wheeler on Tuesday, January 26, 2016 - 06:04 pm:

*Had it running great on mag.. perfect wiring
re newed magneto.. tip top..

Now its starts on batt fine.. but dies when running and switched to mag?

Clues.. a bit damp but over 40F
Started with 6v battery charger hooked up..
I did not let it fully warm up...
weird switch?

Novice owner


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tyrone Thomas - Topeka KS on Tuesday, January 26, 2016 - 06:16 pm:

I have a coupe that has a worn switch that contacts "mag" and sometimes not. How much slop is in your switch? May need to replace the switch.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Henry Petrino in Modesto, CA on Tuesday, January 26, 2016 - 06:37 pm:

Sounds like Tyrone is probably right. Try starting it on battery then when you switch to magneto if/when it starts to die wiggle the switch a little. Could be that just taking the switch apart and cleaning the contacts may fix it, could be you need a new switch, if that's the problem.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Peter Claverie, Memphis TN on Tuesday, January 26, 2016 - 06:49 pm:

Or, it could be that the Magneto contact has gone erratic. That could be from a buildup of lint where it contacts the blob of solder on the mag coil, or it could be that the spring and point have gone haywire, or it could be a simple loose contact of a wire or terminal.

I've just re-read your post. You seem to be knowledgeable about the magneto and wiring, so the idea that it is in the switch seems most likely. But don't discount the possibility of a simple thing, before you dig in to the harder thing(the switch).

AND, BEFORE REMOVING THE SWITCH OR ITS WIRES, BE SURE TO DISCONNECT THE BATTERY. If you should accidentally touch the magneto wire to live battery current, that will de-magnetize your magnets. They can be re-magnetized in the car, but it's a bit of a project. Instructions available here if you need them.


Top of pagePrevious messageNext messageBottom of page Link to this message  By duane wheeler on Tuesday, January 26, 2016 - 06:58 pm:

Heard and understood..

Fix or check the simple stuff first before moving up the ladder of $$$ or effort.

*I also.. might check with meter the mag wire as it runs on batt.. will a 12v tester glow?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Thomas Mullin on Wednesday, January 27, 2016 - 01:00 am:

Duane,

Use a moving needle meter. The idle voltage should be in the 6 to 7 V AC range. Full speed voltage is about 35 to 4 V AC for a great magneto.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Schedler, Sacramento on Wednesday, January 27, 2016 - 01:59 am:

KISS (Keep It Simple S......) (As stated by Duane above.)
Simple things first....check for crud on magneto plug

Don't let ANY DC voltage go to the mag plug


Top of pagePrevious messageNext messageBottom of page Link to this message  By Terry Horlick in Penn Valley, CA on Wednesday, January 27, 2016 - 02:28 am:

On my 1913 I had a nut in the switch come loose and short mag to battery. Result= dead mag. Dead mag requires switch repair then magnets recharged. Destroying mag charge takes less than a second.

TH


Top of pagePrevious messageNext messageBottom of page Link to this message  By Andre Valkenaers on Wednesday, January 27, 2016 - 11:39 am:

This is what I found on a car that died on magneto.

To test your magneto you should make the engine run on battery with the magneto disconnected.
Connect a 12V 21W lamp between the magneto post and the engine ground. Connect your DC Volt meter the same way. You should find 6 to 8 Vdc on idle and over 28Vdc at high speed. Your lamp will blow out while testing but this means your magneto is OK

Good luck
Andre
Belgium


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Carter - South Jersey on Wednesday, January 27, 2016 - 06:13 pm:

"Started with 6v battery charger hooked up.." - Duane, are you sure that the battery charger was not connected to the magneto circuit at some point?


Top of pagePrevious messageNext messageBottom of page Link to this message  By duane wheeler on Wednesday, January 27, 2016 - 08:10 pm:

Interesting.. 6 volt was charging with leads to 6v battery post as I tried to start..

*Also update..

Starts on Batt and runs.. when switching to mag and wigleing key.. I get back fires.. before it starts to die. *I can flip back to Batt to save it.. But wiggleing switch did not settle down the ignition..

Have I blown up the magneto?
Damn!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Dufault on Wednesday, January 27, 2016 - 09:51 pm:

Not the magneto, but keep playing with the switch like that and you may very well blow the muffler...


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Thursday, January 28, 2016 - 11:32 am:

If it backfires when you wiggle the switch in the mag position, I would suspect your trouble is in the ignition switch.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Terry Horlick in Penn Valley, CA on Thursday, January 28, 2016 - 12:18 pm:

A weak mag, but not quite dead, can cause it to miss fire leading to raw fuel mix getting into the tail pipe and causing what Dave shows. Keep flipping it and you may be able to change a bad mag into a dead mag. Right now it sounds like it's "mostly-dead" (a film quote only parents of small children will recognize).

Not to worry Duane, most dead mags will charge up as easily as a mostly-dead mag will. The muffler fix will be a bit more difficult.

TH


Top of pagePrevious messageNext messageBottom of page Link to this message  By duane wheeler on Friday, January 29, 2016 - 04:37 pm:

Ok... novice q?

When all is right.. key to batt
Will the coils always "sing"...??.

SINGING COILS do they signal all is well?

I'm not getting that every start... and still
Have IGNITION trouble switching to mag..

*I THINK NEW SWITCH IN ORDER

Langs?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Dufault on Friday, January 29, 2016 - 04:43 pm:

When all is right.. key to batt
Will the coils always "sing"...??. no

SINGING COILS do they signal all is well? no

I'm not getting that every start... and still
Have IGNITION trouble switching to mag..

*I THINK NEW SWITCH IN ORDER that's best


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Friday, January 29, 2016 - 04:45 pm:

The engine must be in a position so the timer grounds one of the coils - otherwise it can't sing when you turn the key to bat :-)

Do test if there is any output from the magneto post on the hogshead when the engine is running on bat first. If that's the problem, then a new switch won't solve anything..

And if it turns out to be suspected after more testing, then it's quite easily repaired.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Henry Petrino in Modesto, CA on Friday, January 29, 2016 - 04:47 pm:

When you turn the key from "Off" to "Batt" you'll get a coil buzz only if the engine happened to stop with the timer in position to fire a plug. If you turn the crank, then each coil will buzz in turn. Be careful if you try this, sometimes they start or can kick back quite unexpectedly.

The fact that the coils buzz indicates they're getting power. There are lots (well, a few anyway) reasons a T might not start or run, so it really does not indicate "all is well".

I too think it's time for a new switch in your car. Sure, Langs is great.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Jelf, Parkerfield KS on Friday, January 29, 2016 - 05:03 pm:

Pay attention to what Roger said. Before you spend a lot of dough for a new switch you may not need, do the magneto test Andre described. If that shows that the mag is dead, a new switch won't cure it. If the test shows that the mag is working, then the switch may indeed be the problem. If it is, the fix may be simple. But before we get into that, do the test.


Top of pagePrevious messageNext messageBottom of page Link to this message  By R. S. Cruickshank on Friday, January 29, 2016 - 05:39 pm:

I had a weak mag but still operating on mag. During one session of maintenance I decided to tune the coils to make them "hotter". The car started on battery quickly and when switched to mag it died like the switch was turned off. Tried it several times with the same result. I them went back to "what was the last thing done" and started to detune the coils. I got the car running smooth as silk with the coils down to .07. I ran this way for a time but obviously the power was lacking. Re built the mag and all was great.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Schedler, Sacramento on Friday, January 29, 2016 - 07:12 pm:

A good mag will cause a slight increase in engine RPM when switching from BAT to MAG. (6V system)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Andre Valkenaers on Friday, January 29, 2016 - 07:22 pm:

Steve is right.
Test and than do the rest.
For the magneto test the DC (Direct Current)volt meter should be an AC (Alternating Current) volt meter.
Just checked my post and found the mistake.

Sorry
Andre
Belgium


Top of pagePrevious messageNext messageBottom of page Link to this message  By Thomas Mullin on Friday, January 29, 2016 - 07:58 pm:

As Andre says, the Model T magneto puts out alternating current (AC) not direct current (DC). Using a moving needle meter instead of a digital meter damps out jitter and makes it easier to get a reading.


Top of pagePrevious messageNext messageBottom of page Link to this message  By duane wheeler on Tuesday, February 02, 2016 - 02:16 pm:

Did the "test"...

I CLIPPED LEAD TO MAG OUTPUT...ground to exhaust.


12v tester bulb glowed low with T running idle off
Batt position.. Speeding up RPM'S made the light shine brite.

Reving.. light went up and down in intensity.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Strange - Hillsboro, MO on Tuesday, February 02, 2016 - 02:24 pm:

Sounds promising! A switch replacement and an in-car magnet recharge might do the trick. :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Andre Valkenaers on Tuesday, February 02, 2016 - 03:59 pm:

Duane,
Did you use a 21W 12V lamp for the testing??
The 21W is important because of the current the lamp needs 1.75A. This is a little over the current the coils need to start buzzing. Did the lamp blow out at the high RPM??

Andre
belgium


Top of pagePrevious messageNext messageBottom of page Link to this message  By David L Corman on Tuesday, February 02, 2016 - 04:40 pm:

Take switch apart and clean it if you have not already


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