[AT] IH H4 Magneto-no spark

Ken Knierim ken.knierim at gmail.com
Mon May 30 14:04:11 PDT 2011


I can't stress cleanliness enough. Points are very important but on some
models they also have a ground on the coil itself that comes through the
core. I had one of those rusted up on a Fairbanks Morse mag and even with
clean points it wouldn't fire. Cleaning the rust off the core ground made it
clobber me (this from a "it's never going to run again" magneto) and drop it
on the floor when the impulse snapped. It taught me to be careful not to
have MY hand across the output terminal when the impulse snapped too.

Hope this helps.

Ken in AZ

On Mon, May 30, 2011 at 1:05 PM, Doug Tallman <dtallman at accnorwalk.com>wrote:

> Al, Did you clean the new points good. Maybe even some real fine sand
> paper. They can get a film just from setting. Get the ohm meter out. You
> should have somewhere in the 5-10K ohms through the secondary to ground.
> Usually 1-2 ohms through the primary. Make sure none of the wires are
> touching the case. Doug T.
>
>
>
> Al Jones wrote:
> > 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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