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Re: [Shop-talk] It's A Simple Machine, Right?

To: "shop-talk@autox.team.net" <Shop-talk@autox.team.net>
Subject: Re: [Shop-talk] It's A Simple Machine, Right?
From: Jeff Scarbrough <fishplate@gmail.com>
Date: Wed, 2 Jul 2025 17:06:29 -0400
Delivered-to: mharc@autox.team.net
Delivered-to: Shop-talk@autox.team.net
References: <CAO8Q7CO28uMFK_qVdDwZ-OBk=87gcF1_c=qreESced_OnJtt5w@mail.gmail.com>
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The flywheel key!  I didn't think of that - will check tomorrow.  Tehn new
plug, then coil.

You guys are the best!

On Wed, Jul 2, 2025 at 2:31=E2=80=AFPM Jeff Scarbrough <fishplate@gmail.com=
> wrote:

> I've got a puzzle...
>
>  tl;dr - should I try the plug first, skip ahead and replace the coil, or
> is there something else I should try?
>
> The patient is a Snapper rear-engine riding mower, a machine that's as
> simple as can be.  Powered by a B&S Intek 12.5 HP engine, another simple
> machine.
>
> My friend was cutting his grass and managed to get the grass chute tangle=
d
> up in some old fencing.  He got it loose, and continued to mow.  After a
> short distance, the mower quit running and would not restart.
>
> I brought it into my shop and we started troubleshooting. I first tried
> ether - it seemed like it tried for a second, and then nothing.  Pulled t=
he
> plug and it looked wet.  Turned the engine over with the plug connected a=
nd
> grounded, and observed a spark.  Not a magnificent spark, but a spark.
>
> Verified compression, but due to the position of the muffler, I could not
> get *any* of my compression testers to seal in the hole well.  But it
> pushed against my finger with some force.
>
> Moved to the carb.  Pulled and inspected.  Float working, jet clear.
>
> Put it all back together, and nothing.
>
> Pulled the ground wire off the magneto coil and no change.
>
> So, I'm thinking weak coil.  Not completely dead, but not working under
> cylinder pressure.  Something else I read suggested a bad plug - this one
> was installed a month ago and has been working.  Date code on the engine
> indicates it was built on April Fools Day, 2008.
>
> In the era of $15 lawn mower coils, I would throw one on with no qualms.
> But at $40 or $50, I hesitate.
>
> So,  tl;dr - should I try the plug first, skip ahead and replace the coil=
,
> or is there something else I should try?
>
>

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<div dir=3D"ltr">The flywheel key!=C2=A0 I didn&#39;t think of that - will =
check tomorrow.=C2=A0 Tehn new plug, then coil.=C2=A0<div><br></div><div>Yo=
u guys are the best!=C2=A0=C2=A0</div></div><br><div class=3D"gmail_quote g=
mail_quote_container"><div dir=3D"ltr" class=3D"gmail_attr">On Wed, Jul 2, =
2025 at 2:31=E2=80=AFPM Jeff Scarbrough &lt;<a href=3D"mailto:fishplate@gma=
il.com">fishplate@gmail.com</a>&gt; wrote:<br></div><blockquote class=3D"gm=
ail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,=
204,204);padding-left:1ex"><div dir=3D"ltr">I&#39;ve got a puzzle...<div><b=
r></div><div>=C2=A0tl;dr - should I try the plug first, skip ahead and repl=
ace the coil, or is there something else I should try?<br><br>The patient i=
s a Snapper rear-engine riding mower, a machine that&#39;s as simple as can=
 be.=C2=A0 Powered by a B&amp;S Intek 12.5 HP engine, another simple machin=
e.<br><br>My friend was cutting his grass and managed to get the grass chut=
e tangled up in some old fencing.=C2=A0 He got it loose, and continued to m=
ow.=C2=A0 After a short distance, the mower quit running and would not rest=
art.<br><br>I brought it into my shop and we started troubleshooting. I fir=
st tried ether=C2=A0- it seemed like it tried for a second, and then nothin=
g.=C2=A0 Pulled the plug and it looked wet.=C2=A0 Turned the engine over wi=
th the=C2=A0plug connected and grounded, and observed a spark.=C2=A0 Not a =
magnificent spark, but a spark.=C2=A0=C2=A0<div><br></div><div>Verified com=
pression, but due to the position of the muffler, I could not get *any* of =
my compression testers to seal in the hole well.=C2=A0 But it pushed agains=
t my finger with some force.</div><div><br></div><div>Moved to the carb.=C2=
=A0 Pulled and inspected.=C2=A0 Float working, jet clear.</div><div><br></d=
iv><div>Put it all back together, and nothing.=C2=A0=C2=A0<br><br>Pulled th=
e ground wire off the magneto coil and no change.<br><br>So, I&#39;m thinki=
ng weak coil.=C2=A0 Not completely dead, but not working under cylinder pre=
ssure.=C2=A0 Something else I read suggested a bad plug - this one was inst=
alled a month ago and has been working.=C2=A0 Date code on the engine indic=
ates it was built on April Fools Day, 2008.<br><br>In the era of $15 lawn m=
ower coils, I would throw one on with no qualms.=C2=A0 But at $40 or $50, I=
 hesitate.<br><br>So,

=C2=A0tl;dr - should I try the plug first, skip ahead and replace the coil,=
 or is there something else I should try?<br><br></div></div></div>
</blockquote></div>

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