[AJD] magneto question

[Gordon Hart]

Kyle
I work on Mags every once in a while and I suspect if you examine the points 
and the end of the rotor there will be a white corrosion on them take a 
emery board lightly to the points and take a green scouring pad and scuff 
the end of the rotor then cut with scissors a small slice of the pad and 
twist into the terminals where the wires go in the cap turn it until the 
inside is scoured or shinny then scuff the end of the plug wire if it does 
not fire at the plugs then other problems exist. Mag coils get weak and will 
sometimes start tractors when pulled but not when they are hand started. I 
demonstrated this to our JD Collectors club last meeting. This corrosion is 
caused buy moisture which can come in the air hole in the cap. If this 
doesn't work let me know.

Gordon
----- Original Message ----- 
From: "Kyle Sands" <willys_46 at mail.com>
To: "Antique John Deere mailing list" 
<antique-johndeere at lists.antique-tractor.com>
Sent: Saturday, June 17, 2006 11:28 PM
Subject: [AJD] magneto question


> Hello folks - I have what may be a pretty basic magneto question.  I've 
> got a '38 JD B with a Wico C mag.  It's a project tractor that I got 
> running several years ago, but since then, it has been sitting undisturbed 
> but out in the elements - though I have kept the magneto covered and 
> protected.  I decided to start doing some more work on the tractor 
> recently and found that it does not spark anymore.
>
> To get it running back then, I had purchased a rebuilt magneto which of 
> course worked just fine then.  It has less than an hour's worth of 
> run-time on it, so is essentially still brand new.  I pulled the cap and 
> everything looks clean as a whistle, no burn marks, no pitting, no 
> corrosion, nothing that would indicate an obvious problem.  I'm wondering 
> what sorts of issues can arise from non-use that would cause a brand new 
> mag to quit working?  (I do know the problem has to be in the mag and not 
> in the plug wires or plugs because I swapped out those items from my 
> running Model AW and didn't get any spark either.)
>
> Also, to test the mag when it is not installed on the tractor, is it ok to 
> just ground a wire to the mag body and flip the impulse over by hand?  Or 
> is that not going to work or is it inadvisable?
>
> Thanks!
>
> Kyle Sands <><Alexandria, MN
>
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