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Up Topic Welding Industry / General Welding Discussion / mag problem on sa-200
- - By allen white 2 (**) Date 02-22-2011 06:59
hey guys i just finished restoring my 73 i took the mag off and had it all cleaned up and got it reinstalled and found the "kill" stud is grounded out i took it back off took it back to the shop and the guy put all new insulators on it and it ran fine on his testing machine i reinstalled it and the stud is grounded again     do any of you guys haveany suggestions to what could cause it      thanks for any help
Parent - - By Nitesky (**) Date 02-22-2011 13:36
Is it  grounded with the kill wire connected or not connected?
Parent - - By allen white 2 (**) Date 02-22-2011 15:19
it is groundin out with the kill wire from the switch disconnected     a friend told me another shop to take it to this time im takin the whole machine.   ill post up what i find out for everyones future reference
Parent - By Tyler1970 (***) Date 02-22-2011 15:26
If its not connected to the switch on the front on the machine. You might have some wire from the mag to the switch grounding on the frame. Trace it back and make sure its not grounding out inbetween.
Parent - - By Nitesky (**) Date 02-22-2011 15:47
Trying to make clear.  Is the wire to the kill switch grounding out OR is the lug on the mag grounded out even without any wire being connected to it?
Parent - By Cumminsguy71 (*****) Date 02-22-2011 19:10
I'm not a big Sa mechanic but electrical troubleshot cadillacs for years. I think what Tyler is saying is check your wire from the mag to the switch for a short to ground. Seems if you disconnect it from the mag and the switch then put an ohm meter on the wire itself to check for a short to ground. One lead on the wire in question and the other to the frame(usually battery ground works well) and your meter should read open. If it shows an ohm reading then your wire is shorted to ground somewhere, i.e., pinched by a bolt, rubbed thru shielding and touching ground. If your wire shows no resistance to ground then you know it is ok. Not sure on how the mag works entirely but if the lug on the mag is depending on the switch to activate the ground I'd leave my wire disconnted off the mag, put your meter lead on the mag lug, then other on the engine, frame(ground) and check for a reading. If lug is supposed to be isolated it should read open or infinite. If your reading is open, no resistance to ground then I say not a mag issue. I guess you could also do this to the switch, check and see if it is stuck in the position allowing ground all the time, again, not sure on how this switch works but if it is actuated somehow to ground and is stuck in that position it would be grounding out the lug on your mag all the time. When you toggle your ignition switch does this somehow disconnect the ground to the mag? Now, I'm curious to hear how this thing works myself.
Parent - By FixaLinc (****) Date 02-22-2011 21:05
Make sure one of wires connected to the points is not slid over grounding out inside there.  The insulated coil wire, condenser wire, & internal wire or metal strap that may or may not be insulated are what connects on the points.  If those short to ground it won't fire.  Depending on what brand mag there is a metal strap (Wico) or insulated wire (Bosch & FM) goes from that points terminal to the insulated terminal on side of mag housing.  The insulated wire from the coil always goes to the points terminal and can get pinched or a hole in insulation shorting out.  Some coils have a separate bare grounding wire or short wire that has to be grounded inside the mag frame that applies mostly to Wico not Bosch or Fairbanks Morse.  NEVER put battery voltage to the magneto or you will fry and ruin the coil and mag !  That terminal on magnetos only goes to a ground or kill switch.  Seen some use the wrong kind of switches and put voltage to a mag never good.
Parent - - By KSellon (****) Date 02-23-2011 00:51
my mouth is closed....hehehe
Parent - By Cumminsguy71 (*****) Date 02-23-2011 15:58
Oh come on Kaye, spill it! Straighten us hacks out!! LoL!! Were we even remotely close? I'll be honest, I was just guessing off what little I know about how the mag works and going by what was said about the ground but would definitely be interested in learning the real truth from a master!
- - By allen white 2 (**) Date 02-23-2011 00:18
ok guys i took it to the shop again with the machine................verdict is that i dont know how they work i guess................... when your mag is bolted up to the machine the kill stud will be grounded until you turn the mag over because it is grounding back through the coil once the mag turns it looses the ground......... i got it all put back to together and she started and ran fine after a 7 month refurbish shop im almost ready to put it to work
Parent - - By allen white 2 (**) Date 02-23-2011 16:07
kay thinks its funny cause she told that i was overthinking something small lol which is just about it i figure    but it was a good thing how it all happened happened anyway cause the guy that helped me with the mag pointed out that i didnt have the gov timed right anyhow so it wouldnt have ran even if i had tried to start it
Parent - By Cumminsguy71 (*****) Date 02-23-2011 18:04
Good learning experience!
Parent - - By ibeweldingsum (***) Date 02-23-2011 18:13
Get a Pertronix distributor and do away with the headache LOL!!!
Parent - - By NWPAwelder (**) Date 02-26-2011 19:32
I personally will take a mag over a distributor any day. Stand-alone unit in its simplest form. No battery required to energize it in order to make it fire.
Parent - - By JTMcC (***) Date 02-27-2011 02:00
I have 200's with mags and 200's with distributors and I have no problems with magnetos but the distributor machines start easier in all weather and have had fewer ignition maintenance over the years.
The truck won't start without (2) batteries so needing a battery to work is really no concern for me. I might think different if I was dragging the machine around with a couple of mules tho.

JTMcC
Parent - By DaveBoyer (*****) Date 02-27-2011 02:20
" I might think different if I was dragging the machine around with a couple of mules tho."

You just might see something like that in the Amish areas...
Up Topic Welding Industry / General Welding Discussion / mag problem on sa-200

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