Sun Aug 18, 2013 3:13 pm
I don't have a magneto ignition wiring diagram for my 1950 Cub. I think I understand why I don't have any spark, but I don't want to take a chance on burning something out. A medium diameter yellow wire runs to the back of the lighting switch from the front terminal of the voltage regulator. Right now, the end of the yellow wire is wrapped with electrical tape and is NOT connected to the regulator terminal. I assume the yellow wire should be connected to that regulator terminal. I don't know why the previous owner used the tape, but I assume he wrapped the whole connection, and it has just come loose. 2nd question: am I correct that the single-terminal "ignition" switch is simply a kill switch? (And that the green wire between the side of the magneto and the kill switch carries the "kill" message?) Thanks for the help.
Sun Aug 18, 2013 5:32 pm
Operator's Manuals, top of page. Manuals contain wiring diagrams. The 1955 manual contains several wiring diagrams, including magneto ignition. You may need to search several operator's manuals or the service manual to come up with the correct wiring diagram for you tractor.
The magneto kill switch located on the dash simply grounds out the magneto.
Sun Aug 18, 2013 5:44 pm
Is it a Magneto and a Cut-out or a Magneto with a Regulator
a Magneto with a Regulator
Forum Family. And you have come to the right place for all things Cub related. If you click on the Site Rules, Regulations, & Important Information
, it will point you to
the Welcome Wagon
wherein you will find links to many useful sites and topics. One of the most important resources are Owner's Manuals, Parts Catalogs and Service Manuals. The Cub Manual Server
is the home of the jpg versions and the PDF Manuals
-- well the pdf's of course
Sun Aug 18, 2013 8:47 pm
Thanks all. The pdf diagram "6 volt magneto ignition below sn 210,000" shows my system. The disconnected wire on the front voltage regulator terminal on my Cub explains why the lights don't work. However, it seems that as long as the ignition/kill switch is "on" (pulled out) I should get sparks. What should I look for now??
Sun Aug 18, 2013 9:07 pm
The mag is independent of the electrical system. The wire from the switch to the mag just throws a ground to the mag to shut it off. Try unhooking the wire from the mag in case the switch is bad. Then go points and condenser, then coil in that order.
Mon Aug 19, 2013 12:13 pm
Thanks to the pdf wiring diagram and my own very, very slow reasoning process, I became suspicious that the magneto was indeed independent of the rest of the electrical system - thanks, Cecil, for confirming that. If I've got it right (except for the starter motor) I shouldn't even need a battery to get good sparks. I am not getting anything. I confirmed that the magneto was grounded out with the kill switch closed. It was STILL grounded out with the kill switch pulled out (open). So I assumed that the switch was bad and disconnected the wire from the mag as suggested. Here's my new mystery: the terminal on the mag still shows it's grounded out - zero ohms between it and ground. What the heck does that mean?! (I haven't gone to the points, etc. yet.)
Mon Aug 19, 2013 12:49 pm
If the points are closed it will still show a ground, in the range of 1 or 2 ohms.
Mon Aug 19, 2013 1:31 pm
Brian50 wrote:Here's my new mystery: the terminal on the mag still shows it's grounded out - zero ohms between it and ground. What the heck does that mean?!
John *.?-!.* cub owner wrote:If the points are closed it will still show a ground, in the range of 1 or 2 ohms.
Normal. It will also display low ohm's reading because one primary wire of the coil winding, one side of the condenser, and one side of the points are attached to the terminal on the side of the magneto.
Depending on magneto internal wiring, points open or closed there are several other paths to ground besides the points.
Mon Aug 19, 2013 8:03 pm
Welcome to the forum!
Mon Aug 19, 2013 8:07 pm
Besides the points, check the lug .. make sure the insulating washers are there to isolate it from the case.
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