[AT] tractor electrical question

[Howard Pletcher]

It's not unheard of, particularly since many of those parts now come from
overseas.  To me, swapping with another if you can find something to swap
with would be the easiest way to prove or eliminate that as a possibility.

Make sure your points setting is close to spec and they are clean as that
would affect the ignition.  Have you looked at your plugs, not thinking
that's the problem, but if they are fouled or badly gapped, they could have
an effect.  You also might run it until it heats up and needs the 12V to
see if it still shows 6V to the coil.  If not, then it's somewhere else in
the circuit.

Many of the other things suggested have no connection with the ignition
circuit.

On Thu, Aug 26, 2021 at 5:12 PM John Hall <jtchall at nc.rr.com> wrote:

> Howard, you are leaning toward new coil and old coil are both bad?
>
> John Hall
>
> On 8/26/2021 3:47 PM, Howard Pletcher wrote:
>
> No, what he is reporting is just what should be happening.  With the
> points open, no current is flowing through the primary circuit and there is
> 12V at the + side of the coil.  When he bumped the starter and closed the
> points, the current flowing through the resistor in the primary circuit
> results in a voltage drop so that there is now 6V on the coil as intended.
>
> The wire from the starter to the coil does send 12V directly to the coil,
> but this is only engaged while the starter is cranking in order to produce
> a hotter spark for starting and is not connected to 12V  the rest of the
> time.
>
> The fact the coil seems to require 12V to its terminal when hot points to
> an internal problem in the coil as discussed by Dell in the Yesterday's
> Tractors article.
>
> Howard
>
>
>
> On Thu, Aug 26, 2021 at 2:53 PM Carl Szabelski <c.s.szabelski at gmail.com>
> wrote:
>
>>  By the way, I believe it’s not the coil and is related to the cranking
>> motor. Especially since the voltage drops when you bump it like you said.
>> Something in the motor may be partially shorted or corroded, causing a
>> voltage drop to the coil. The coil should always see 12V whether or not
>> there is a resistor, internal or external. The resistor is essentially
>> after the coil winding and drops the voltage after the winding, not before
>> it. If the engine is running fine when you directly connect 12V to the
>> coil, the coil is working like it should and is good.
>>
>> Carl
>>
>>
>>
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-- 
Howard
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