[AT] IH H4 Magneto-no spark

[charlie hill]

Al, this is not a likely solution but more of a story to illustrate the need 
to look for the not so obvious but easy solutions.  My only direct 
experience with magnetos is my Fairbanks Morse ZC engine.  When I got it the 
previous owner had knocked a hole in the corner of the mag cover and wired 
an automotive coil into the mag so I figured the coil was shot.  Well I got 
to looking around, then did some reading and some more looking and that is 
when I stumbled on the problem.  There was a wire from the original F-M coil 
to a lug on the side of the case.  The wire is for the kill switch.  Well it 
just so happened that the insulation had rubbed off the wire and it was 
going to ground on the inside of the mag case in such a way as to create a 
permanent kill switch.  A new wire, or maybe I just taped up the old one and 
some JB Weld to fix the mag cover and it's been firing ever since.

I guess my point is, examine everything closely.

Charlie

-----Original Message----- 
From: Al Jones
Sent: Monday, May 30, 2011 3:37 PM
To: at at lists.antique-tractor.com ; farmall at lists.antique-tractor.com
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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