[AT] IH H4 Magneto-no spark

[john hall]

Al, set your points on .013". If you suspect they are oxidized, polish them. 
Pull the coil cover off and lay a screwdriver on the magneto housing and 
just above the primary lead out on the coil and check for spark. If the coil 
is spongy, cracked or if you see signs of an oily residue dripping onto the 
rotor from the coil, order a new one. If you have spark at the coil, then 
just work outward by polishing where all the wires plug in--I use very fine 
steel wool.

FYI. when I get a mag such as yours to rebuild, I replace points coil and 
condenser without the slightest hesitation. The parts are too cheap not to.

John Hall


----- Original Message ----- 
From: "Al Jones" <farmallsupera at earthlink.net>
To: <at at lists.antique-tractor.com>; <farmall at lists.antique-tractor.com>
Sent: Monday, May 30, 2011 3:37 PM
Subject: [AT] IH H4 Magneto-no spark


> Started tinkering on the white Super A this afternoon.  Magneto impulse 
> clicks when you hand crank the engine, was hoping I could just rub the 
> points a little and make fire.  When I got the breaker cover off, I saw 
> the leaf spring on the moving point had broken.  I had a new point and 
> condenser set lying around, so I went ahead and took the mag off and 
> replaced all that.  Condenser was tricky but I got it.  Had a time getting 
> the screw loose on the stationary point but I got that apart and since I 
> couldn't find my feeler gauge anywhere, I used a piece of the cardboard 
> boxtop to set the points.  Backwoodsy-hillbilly but the points connect and 
> break so I felt like that was in the ballpark.
>
> Long story short I still have no spark.  The inside of the distributor cap 
> looks pretty corroded, so I tried pulling the wire from the coil cover to 
> the dist. cap and trying to get a spark from there (trying to arc it off 
> the side of the engine block) but still no spark.  The connection in the 
> coil cover looks pretty good, and the inside "tab" that touches the coil 
> itself is bright, shiny copper. (The coil cover could be original.  It has 
> the old IHC trademark instead of the IH "man on a tractor" logo)  I did 
> knock the glaze off the dimple on the coil, and on the rotor button.
>
> The only thing I can think of is the coil itself.  Looks like given the 
> condition of everything that I could get some spark from the coil 
> terminal.  What else should I look for?
>
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