[AT] tractor electrical question

[Carl Szabelski]

https://cdn.compknowhow.com/carterandgruenewald/wiring_diagrams/IH%2054-74-84%20SERIES.pdf

John

Don’t know which version of the above link applies to your tractor, but if
you look at the first sheet, the battery goes to a contact on the cranking
motor, and then from a second contact to the coil. When putting a wire from
the battery directly to the coil, you’re bypassing the cranking motor. I
would check out the cranking motor and it’s associated contacts.

Carl

On Wednesday, August 25, 2021, John Hall <jtchall at nc.rr.com> wrote:

> Got what I hope is a simple question. On my IH 454 tractor, is the voltage
> going to the coil a constant 12V? I'm having some issues with it running
> bad when it gets hot (I've already replaced everything but the plug wires).
> Found out today that if I run a jumper wire from battery to the coil, the
> problem goes away. Take it off problem comes back, put it back it goes
> away, take it off, it comes back. So I am tracing the wiring but this one
> isn't simple, new enough there are tons of gauges, fuel solenoids, safety
> switches, etc. Anyway, if I check voltage at the coil, the fuel solenoid,
> and there is one small terminal on starter solenoid that all read 12V if
> the switch is on. If I bump the engine over slightly (I guess the pts are
> closing) then the coil and starter drop to just under 6V, fuel solenoid
> stays the same. So shouldn't there always be 12V at the coil?
>
> John Hall
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