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WC with a magneto

S

SDE

Well-known Member
There is a pull switch that under a normal operation, pull out is on. With a magneto, out grounds the magneto, Correct? The switch appears to need to be replaced. It looks bent.

The switch has a wire that goes to the magneto. I wanted to be sure that the wire was tight on the stud. It was, but the stud is loose in the magneto. Is the stud just connected to the case of the magneto, or is there a wire inside the magneto that I will need to verify is attached to the stud?
TY
SDE
 
The stud coming out of the magneto should be tight. If it is loose, it could damage the insulating washers or allow the wire terminal inside that connects the stud to the points to rotate enough to contact the magneto case and ground out the mag. Disconnect the switch to isolate the magneto and use a multimeter to test for an internal ground by touching the stud and the magneto casing with the meter's probes to check for continuity. There shouldnt be any. If there is, try rotating the stud slightly to see if the unwanted connection can be broken. It is an easy fix to make once the cap is off, but you might get lucky and be able to tighten the nut on the stud with an ignition wrench from the outside.

Re-check for continuity when finished!
 
Some switches are off (grounded) when In and others are grounded when out. I have seen both kinds. so use a ohm meter to see whish way grounds the attachment terminal. (done with the switch disconnected). As others indicate, the mag has a wire inside connected to the terminal that should not be loose. It will appear grounded if the points in the mag are closed. looking at the connection on the inside should allow visual confirmation that the connection is not grounded to the mag housing accidently. Jim
 
(quoted from post at 09:56:51 05/17/21) If the points are closed it will show continuity.
Click to expand...


Even with the breaker points "open" there will be continuity/relatively low resistance from the "kill" terminal to the mag's "case"/ground though the primary coil winding.
 
Typically grounding the mags external kill switch terminal kills the spark as the points are in effect grounded. Its easy with a continuity checker or an ohm meter on the low Rx1 ohms scale to see which switch position does what and if its working. RUN/ON position no ground path (IE Open) to kill terminal,,,,,,,, OFF position creates a path to ground for the mags external kill terminal.

John T
 
AS per Warbaby's instruction's,

Disconnect the switch to isolate the magneto and use a multimeter to test for an internal ground by touching the stud and the magneto casing with the meter's probes to check for continuity. There shouldnt be any. If there is, try rotating the stud slightly to see if the unwanted connection can be broken.

My meter goes from 1 to zero, regardless of how I rotate the stud. I removed the cap, but it appears that I will need to remove stuff from inside the mag to get deep enough to reach the stud. REALLY don't want to do that. I will try to use a mirror to look inside it.
TY
SDE
 
Going deeper is not difficult, just take a clear picture of the position of the rotor with the cap off. It is timed and must be put back the exact position. Jim
 
After trying to adjust the stud again, I have decided to try to sell it as a non running tractor. I give up, I quit, at least until I can regenerate some physical and mental abilities.
TY
SDE
 
(quoted from post at 12:26:20 05/17/21) AS per Warbaby's instruction's,

Disconnect the switch to isolate the magneto and use a multimeter to test for an internal ground by touching the stud and the magneto casing with the meter's probes to check for continuity. There shouldnt be any. If there is, try rotating the stud slightly to see if the unwanted connection can be broken.

My meter goes from 1 to zero, regardless of how I rotate the stud. I removed the cap, but it appears that I will need to remove stuff from inside the mag to get deep enough to reach the stud. REALLY don't want to do that. I will try to use a mirror to look inside it.
TY
SDE
Click to expand...


I'll try this one more time, due to the coil primary winding shunting the "kill" stud to ground, even WITH the points "open" there WILL be continuity to ground.

When checked with an Ohmmeter that's accurate at low Ohms readings you will be measuring the resistance of the coil primary, just a few Ohms.
 
Thank you. I did have a few readings that were point something. I assumed that I wasn't making solid contact. Tomorrow I will try it again
TY
SDE
 
Can you send the mag to me? I do them as a hobby. Won't cost much more than shipping. Tractor will sell better if it is running.
 
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