Someone gave us this non working self propelled mower that he says
just stopped working. When my son first tried to start it he says that
it would run for a few seconds and then quit. After this it would
apparently take about 20 minutes before it would again start, and
again run for about two seconds and then the process was repeated.
This morning we worked on it a little and I could not get it started
at all. We ultimately found that there was no spark. I don't know what
happened when he worked on it. The ignition kill switch is working,
There is no short on that terminal in "run" position, the rust has
been cleaned off both the rotor and stator areas of the flywheel and
transformer and the plug of course looks OK too. There are no points
or capacitor on this mower and there is just a magnet on the
flywheel.The coil has a secondary wire to the plug, a terminal that is
grounded to the transformer laminations with a self taping screw, and
a terminal connected to the kill switch. Unless I'm missing something
the operation of this system seems pretty cut and dried without
timing or anything else being an issue, that as the magnet passes by
the coil a voltage should be induced into the secondary. Am I correct
in this assumption? Is there a way the positively bench test this coil
before we go out a buy a new one that will no doubt be non returnable
if it's not needed? Thanks, Lenny

On Sat, 1 Sep 2012 12:57:03 -0700 (PDT), klem kedidelhopper
wrote:

Someone gave us this non working self propelled mower that he says
just stopped working. When my son first tried to start it he says that
it would run for a few seconds and then quit. After this it would
apparently take about 20 minutes before it would again start, and
again run for about two seconds and then the process was repeated.
This morning we worked on it a little and I could not get it started
at all. We ultimately found that there was no spark. I don't know what
happened when he worked on it. The ignition kill switch is working,
There is no short on that terminal in "run" position, the rust has
been cleaned off both the rotor and stator areas of the flywheel and
transformer and the plug of course looks OK too. There are no points
or capacitor on this mower and there is just a magnet on the
flywheel.The coil has a secondary wire to the plug, a terminal that is
grounded to the transformer laminations with a self taping screw, and
a terminal connected to the kill switch. Unless I'm missing something
the operation of this system seems pretty cut and dried without
timing or anything else being an issue, that as the magnet passes by
the coil a voltage should be induced into the secondary. Am I correct
in this assumption? Is there a way the positively bench test this coil
before we go out a buy a new one that will no doubt be non returnable
if it's not needed? Thanks, Lenny
It's been a long time since I worked on lawn mower engines, but every
one I ever saw had points and a capacitor. On vertical shaft engines
they were typically under a cover under the flywheel. Now I will
admit that this experience was well before the wide spread use of
solid state devices, but there MUST be some method of interupting the
primary circuit as the crankshaft nears top dead center. Also, the
presence of a capacitor is pretty well mandatory.

PlainBill

klem kedidelhopper wrote:
Someone gave us this non working self propelled mower that he says
just stopped working. When my son first tried to start it he says that
it would run for a few seconds and then quit. After this it would
apparently take about 20 minutes before it would again start, and
again run for about two seconds and then the process was repeated.
This morning we worked on it a little and I could not get it started
at all. We ultimately found that there was no spark. I don't know what
happened when he worked on it. The ignition kill switch is working,
There is no short on that terminal in "run" position, the rust has
been cleaned off both the rotor and stator areas of the flywheel and
transformer and the plug of course looks OK too. There are no points
or capacitor on this mower and there is just a magnet on the
flywheel.The coil has a secondary wire to the plug, a terminal that is
grounded to the transformer laminations with a self taping screw, and
a terminal connected to the kill switch. Unless I'm missing something
the operation of this system seems pretty cut and dried without
timing or anything else being an issue, that as the magnet passes by
the coil a voltage should be induced into the secondary. Am I correct
in this assumption? Is there a way the positively bench test this coil
before we go out a buy a new one that will no doubt be non returnable
if it's not needed? Thanks, Lenny

Have you downloaded the manual from Toro.com? May have a troubleshooting
guide...

Otherwise regular small engine repair books should be enough to get
through the lack of spark problem.

John :-#)#

--
(Please post followups or tech enquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

On Sep 1, 6:37*pm, John Robertson wrote:
klem kedidelhopper wrote:
Someone gave us this non working self propelled mower that he says
just stopped working. When my son first tried to start it he says that
it would run for a few seconds and then quit. After this it would
apparently take about 20 minutes before it would again start, and
again run for about two seconds and then the process was repeated.
This morning we worked on it a little and I could not get it started
at all. We ultimately found that there was no spark. I don't know what
happened when he worked on it. The ignition kill switch is working,
There is no short on that terminal in "run" position, the rust has
been cleaned off both the rotor and stator areas of the flywheel and
transformer and the plug of course looks OK too. There are no points
or capacitor on this mower and there is just a magnet on the
flywheel.The coil has a secondary wire to the plug, a terminal that is
grounded to the transformer laminations with a self taping screw, and
a terminal connected to the kill switch. Unless I'm missing something
the operation of this system *seems pretty cut and dried without
timing or anything else being an issue, that as the magnet passes by
the coil a voltage should be induced into the secondary. Am I correct
in this assumption? Is there a way the positively bench test this coil
before we go out a buy a new one that will no doubt be non returnable
if it's not needed? Thanks, Lenny

Have you downloaded the manual from Toro.com? May have a troubleshooting
guide...

Otherwise regular small engine repair books should be enough to get
through the lack of spark problem.

John :-#)#

--
* * (Please post followups or tech enquiries to the newsgroup)
* John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
* Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
* * * * * * * * * * *www.flippers.com
* * * *"Old pinballers never die, they just flip out."

These appear to be owners manuals. How to change the oil, etc. There
really isn't anything mentioned that goes into anything that technical
like bench testing a coil. I really think it is the coil. I just don't
want to order one, about 20.00 and then possibly be stuck with it.
Anyone have any ideas? Thanks, Lenny

klem kedidelhopper wrote:
...
Anyone have any ideas? Thanks, Lenny

I just went through this. I didn't want to believe that the coil was
bad (a new one was $40). But there isn't a way, that I know of, to
bench test. If you don't have a spark, it's bad.

To test:
- remove the kill wire
- remove the spark plug, attach the coil wire, & ground the plug
- pull the cord & watch for a spark on the plug

This is better than trying to get a spark between the coil wire & ground.

Bob

On Sep 2, 9:05*am, Bob Engelhardt wrote:
klem kedidelhopper wrote:
...
Anyone have any ideas? Thanks, Lenny

I just went through this. *I didn't want to believe that the coil was
bad (a new one was $40). *But there isn't a way, that I know of, to
bench test. *If you don't have a spark, it's bad.

To test:
- remove the kill wire
- remove the spark plug, attach the coil wire, & ground the plug
- pull the cord & watch for a spark on the plug

This is better than trying to get a spark between the coil wire & ground.

Bob

Wow, 40.00 for a coil! I am probably facing the same thing. I hope you
at least got a kiss out of it...Lenny

On Sun, 2 Sep 2012 05:35:19 -0700 (PDT), klem kedidelhopper
wrote:

On Sep 1, 6:37*pm, John Robertson wrote:
klem kedidelhopper wrote:
Someone gave us this non working self propelled mower that he says
just stopped working. When my son first tried to start it he says that
it would run for a few seconds and then quit. After this it would
apparently take about 20 minutes before it would again start, and
again run for about two seconds and then the process was repeated.
This morning we worked on it a little and I could not get it started
at all. We ultimately found that there was no spark. I don't know what
happened when he worked on it. The ignition kill switch is working,
There is no short on that terminal in "run" position, the rust has
been cleaned off both the rotor and stator areas of the flywheel and
transformer and the plug of course looks OK too. There are no points
or capacitor on this mower and there is just a magnet on the
flywheel.The coil has a secondary wire to the plug, a terminal that is
grounded to the transformer laminations with a self taping screw, and
a terminal connected to the kill switch. Unless I'm missing something
the operation of this system *seems pretty cut and dried without
timing or anything else being an issue, that as the magnet passes by
the coil a voltage should be induced into the secondary. Am I correct
in this assumption? Is there a way the positively bench test this coil
before we go out a buy a new one that will no doubt be non returnable
if it's not needed? Thanks, Lenny

Have you downloaded the manual from Toro.com? May have a troubleshooting
guide...

Otherwise regular small engine repair books should be enough to get
through the lack of spark problem.

John :-#)#

--
* * (Please post followups or tech enquiries to the newsgroup)
* John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
* Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
* * * * * * * * * * *www.flippers.com
* * * *"Old pinballers never die, they just flip out."

These appear to be owners manuals. How to change the oil, etc. There
really isn't anything mentioned that goes into anything that technical
like bench testing a coil. I really think it is the coil. I just don't
want to order one, about 20.00 and then possibly be stuck with it.
Anyone have any ideas? Thanks, Lenny
Yes. Look he
http://home.howstuffworks.com/home-i...l-engines3.htm

The pictorial diagram and the two pictures match what I remember from
50 years ago. I also see references to solid state ignition systems
used on these engines, that came well after the time I worked on them.

If you can pull the coil without finding any wires other than to the
kill switch and to the spark plug, the problem must be either the
coil, the magnet in the flywheel, the spark plug, or the spark plug
wire. The spark plug would seem to be the only replaceable part other
than the coil.

PlainBill

On Sat, 1 Sep 2012 12:57:03 -0700 (PDT), klem kedidelhopper
wrote:

Someone gave us this non working self propelled mower that he says
just stopped working.

Model number of the Toro mower?


When my son first tried to start it he says that
it would run for a few seconds and then quit.

How many seconds is a few? If it's about 2-4 seconds, then you've got
spark and some fuel. My guess(tm) is that you have a clogged fuel
filter at the end of a hose banging around in the fuel tank. Fish out
the fuel filter and hose with a coat hanger and replace the filter.
No, don't try to clean it... just replace it. There may also be a
filter at the fuel entry hose to the carb.

After this it would
apparently take about 20 minutes before it would again start, and
again run for about two seconds and then the process was repeated.

Yep. It takes that long for fuel to sloooooooowly ooooooze through
the clogged fuel filter.

This morning we worked on it a little and I could not get it started
at all.

Sigh. One giant step backwards.

We ultimately found that there was no spark.

Remove spark plug. Reconnect wire from ignition coil. Ground the
plug some place convenient on the engine (not the gas tank). Crank.
Do you see sparks? If not, check the points.

There are no points
or capacitor on this mower and there is just a magnet on the
flywheel.

Keep looking. The breaker points and condenser might be buried.
http://home.howstuffworks.com/home-improvement/repair/how-to-repair-small-engines3.htm
http://www.ehow.com/how-does_5008999_lawn-mower-magneto-work.html
Perhaps if you supplied the model number, an exploded view might be
found?

How to test a magneto:
http://www.ask.com/questions-about/How-to-Test-a-Magneto

Shopping and todo list:
1. Fuel filter
2. Points and condenser.
3. Replace fuel line hoses if they're plugged or cracking.
4. Spark plug.
5. Clean out engine exhaust port from carbon buildup.
6. Clean out engine intake port from tar buildup.
7. Carb cleaner.
8. Check the magneto gap.
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Jeff Liebermann wrote:
On Sat, 1 Sep 2012 12:57:03 -0700 (PDT), klem kedidelhopper
....
There are no points
or capacitor on this mower and there is just a magnet on the
flywheel.

Keep looking. The breaker points and condenser might be buried. ...

Lawnmowers haven't had points for 20 (30?, 40?) years.

On Mon, 03 Sep 2012 09:22:34 -0400, Bob Engelhardt
wrote:

Jeff Liebermann wrote:
On Sat, 1 Sep 2012 12:57:03 -0700 (PDT), klem kedidelhopper
...
There are no points
or capacitor on this mower and there is just a magnet on the
flywheel.

Keep looking. The breaker points and condenser might be buried. ...

Lawnmowers haven't had points for 20 (30?, 40?) years.

True. I hate it when I date myself. I haven't had a lawn for about
35 years. We don't have lawns in the deep dark forest. Most of my
small engine repairs are on chain saws and weed whackers, many of
which have points and condensers.

If it's an old riding mower, it has points and condenser on the
engine. If it's newer, it's an electronic ignition. I'll wait for
the model number to be disclosed to be certain.

My comments on the fuel system problems still apply.





--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Sat, 1 Sep 2012 12:57:03 -0700 (PDT), klem kedidelhopper
wrote:

Someone gave us this non working self propelled mower that he says
just stopped working. When my son first tried to start it he says that
it would run for a few seconds and then quit. After this it would
apparently take about 20 minutes before it would again start, and
again run for about two seconds and then the process was repeated.
This morning we worked on it a little and I could not get it started
at all. We ultimately found that there was no spark. I don't know what
happened when he worked on it. The ignition kill switch is working,
There is no short on that terminal in "run" position, the rust has
been cleaned off both the rotor and stator areas of the flywheel and
transformer and the plug of course looks OK too. There are no points
or capacitor on this mower and there is just a magnet on the
flywheel.The coil has a secondary wire to the plug, a terminal that is
grounded to the transformer laminations with a self taping screw, and
a terminal connected to the kill switch. Unless I'm missing something
the operation of this system seems pretty cut and dried without
timing or anything else being an issue, that as the magnet passes by
the coil a voltage should be induced into the secondary. Am I correct
in this assumption? Is there a way the positively bench test this coil
before we go out a buy a new one that will no doubt be non returnable
if it's not needed? Thanks, Lenny
Greetings Lenny,
The electronics in the coil are probably bad. If you try the test
suggested further down this thread and there is still no spark then it
is very likely the electronics are bad. I have seen some coils that
have the trigger electronics located in a bump on the coil. These
types can sometimes be removed and replaced with aftermarket
electronic ignition modules. It has been a long time since I've done
this so maybe this won't work for you. The magneto works like this:
the primary is grounded and the magnet passes quickly past the legs of
the magneto assembly. At the proper moment the ground is disconnected
and the collapsing field induces a voltage in the secondary. The
aftermarket electronic ignitions sense the rising voltage and open the
ground connection at the proper moment. So if you can get to the
electronics and remove the connections, then figure out which wires
are which, you can then maybe use an aftermarket module to make the
thing work. Briggs and Stratton used to make an electronic ignition
that worked differently than described above. It had some sort of coil
that sensed the flywheeel position(Ithink). I never tried to hack one
of those, just replaced parts. But I have repaired a few of the types
described above. I have even just wired in an aftermarket electronic
ignition on a weed trimmer that lost spark. The ignition module was
made for a Tecumseh engine but since I had it already I just wired it
the way I would have if I was retrofitting a points type ignition. The
weed trimmer unit had obviously failed with the ground permanently
connected and since the new module opens the ground to get spark it
worked fine. If you don't mind a shock you can try what I do. I grab
the spark plug wire and pull slowly on the starting rope. If I don't
get even a tingle then I pull faster. If I get a good shock then that
means either a bad spark plug or bad connections. If I just get a
pretty good tingle then that probably means that the coil is being
permanently grounded and I'm feeling the rising field. This is hopeful
because it means that maybe an aftermarket ignition module will work
since they just interrupt the ground. Whew! I didn't think this reply
would be so long.
Eric

On Sep 4, 11:39*am, wrote:
On Sat, 1 Sep 2012 12:57:03 -0700 (PDT), klem kedidelhopper









wrote:
Someone gave us this non working self propelled mower that he says
just stopped working. When my son first tried to start it he says that
it would run for a few seconds and then quit. After this it would
apparently take about 20 minutes before it would again start, and
again run for about two seconds and then the process was repeated.
This morning we worked on it a little and I could not get it started
at all. We ultimately found that there was no spark. I don't know what
happened when he worked on it. The ignition kill switch is working,
There is no short on that terminal in "run" position, the rust has
been cleaned off both the rotor and stator areas of the flywheel and
transformer and the plug of course looks OK too. There are no points
or capacitor on this mower and there is just a magnet on the
flywheel.The coil has a secondary wire to the plug, a terminal that is
grounded to the transformer laminations with a self taping screw, and
a terminal connected to the kill switch. Unless I'm missing something
the operation of this system *seems pretty cut and dried without
timing or anything else being an issue, that as the magnet passes by
the coil a voltage should be induced into the secondary. Am I correct
in this assumption? Is there a way the positively bench test this coil
before we go out a buy a new one that will no doubt be non returnable
if it's not needed? Thanks, Lenny

Greetings Lenny,
The electronics in the coil are probably bad. If you try the test
suggested further down this thread and there is still no spark then it
is very likely the electronics are bad. I have seen some coils that
have the trigger electronics located in a bump on the coil. These
types can sometimes be removed and replaced with aftermarket
electronic ignition modules. It has been a long time since I've done
this so maybe this won't work for you. The magneto works like this:
the primary is grounded and the magnet passes quickly past the legs of
the magneto assembly. At the proper moment the ground is disconnected
and the collapsing field induces a voltage in the secondary. The
aftermarket electronic ignitions sense the rising voltage and open the
ground connection at the proper moment. So if you can get to the
electronics and remove the connections, then figure out which wires
are which, you can then maybe use an aftermarket module to make the
thing work. Briggs and Stratton used to make an electronic ignition
that worked differently than described above. It had some sort of coil
that sensed the flywheeel position(Ithink). I never tried to hack one
of those, just replaced parts. But I have repaired a few of the types
described above. I have even just wired in an aftermarket electronic
ignition on a weed trimmer that lost spark. The ignition module was
made for a Tecumseh engine *but since I had it already I just wired it
the way I would have if I was retrofitting a points type ignition. The
weed trimmer unit had obviously failed with the ground permanently
connected and since the new module opens the ground to get spark it
worked fine. If you don't mind a shock you can try what I do. I grab
the spark plug wire and pull slowly on the starting rope. If I don't
get even a tingle then I pull faster. If I get a good shock then that
means either a bad spark plug or bad connections. If I just get a
pretty good tingle then that probably means that the coil is being
permanently grounded and I'm feeling the rising field. This is hopeful
because it means that maybe an aftermarket ignition module will work
since they just interrupt the ground. Whew! I didn't think this reply
would be so long.
Eric

Wow Eric thanks for the theory. I think that it is a good bet that the
electronics in the coil has failed. I'm pretty sure that I can get a
used coil from a lawnmower repair guy in this area. There are a number
of people that work on these and sell used mowers. I'm thinking that
they must keep used parts around. I wish I could find the model number
of this thing. Lenny

On Wed, 5 Sep 2012 10:18:38 -0700 (PDT), klem kedidelhopper
wrote:

I wish I could find the model number
of this thing. Lenny

Ask and ye shall receive:
http://www.jackssmallengines.com/toro_model_locator.cfm


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Sep 5, 1:52*pm, Jeff Liebermann wrote:
On Wed, 5 Sep 2012 10:18:38 -0700 (PDT), klem kedidelhopper

wrote:
I wish I could find the model number
of this thing. Lenny

Ask and ye shall receive:
http://www.jackssmallengines.com/toro_model_locator.cfm

--
Jeff Liebermann * *
150 Felker St #D * *http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann * * AE6KS * *831-336-2558

How do you find this **** Jeff? It's a model 20016. Lenny

On Wed, 5 Sep 2012 12:06:48 -0700 (PDT), klem kedidelhopper
wrote:

On Sep 5, 1:52*pm, Jeff Liebermann wrote:
On Wed, 5 Sep 2012 10:18:38 -0700 (PDT), klem kedidelhopper

wrote:
I wish I could find the model number
of this thing. Lenny

Ask and ye shall receive:
http://www.jackssmallengines.com/toro_model_locator.cfm

How do you find this **** Jeff? It's a model 20016. Lenny

I usually use a crystal ball. However, it's in the shop getting its
temporal dimensional translator recalibrated. So, I had to settle for
Google. A search for "Toro find serial number" immediately yielded
the correct site on the first page (at the bottom).

Here's the exploded view of the 20016:
http://www.ereplacementparts.com/toro-20016-2600000012609999992006-lawn-mower-parts-c-121776_127291_127648.html
Looking at the engine diagram, there are no points or condenser. Ok
so I was wrong. Ignition coil:
http://www.ereplacementparts.com/ignitionstate-solid-p-685744.html
Oh swell... it's a special order. Digging for other vendors that
carry a 34443D.
http://www.ebay.com/sch/i.html?_nkw=34443d+coil
$25.

However, I'm still suspicious that it's a fuel problem based on the
original symptoms. I'm not sure why it now doesn't have a spark.
Performing at least one of several recommended test should help
eliminate lack of spark as a probable cause.





--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Sep 6, 3:18*am, Jeff Liebermann wrote:
On Wed, 5 Sep 2012 12:06:48 -0700 (PDT), klem kedidelhopper

wrote:
On Sep 5, 1:52*pm, Jeff Liebermann wrote:
On Wed, 5 Sep 2012 10:18:38 -0700 (PDT), klem kedidelhopper

wrote:
I wish I could find the model number
of this thing. Lenny

Ask and ye shall receive:
http://www.jackssmallengines.com/toro_model_locator.cfm
How do you find this **** Jeff? It's a model 20016. Lenny

I usually use a crystal ball. *However, it's in the shop getting its
temporal dimensional translator recalibrated. *So, I had to settle for
Google. *A search for "Toro find serial number" immediately yielded
the correct site on the first page (at the bottom).

Here's the exploded view of the 20016:
http://www.ereplacementparts.com/toro-20016-2600000012609999992006-la...
Looking at the engine diagram, there are no points or condenser. *Ok
so I was wrong. *Ignition coil:
http://www.ereplacementparts.com/ignitionstate-solid-p-685744.html
Oh swell... it's a special order. *Digging for other vendors that
carry a 34443D.
http://www.ebay.com/sch/i.html?_nkw=34443d+coil
$25.

However, I'm still suspicious that it's a fuel problem based on the
original symptoms. *I'm not sure why it now doesn't have a spark.
Performing at least one of several recommended test should help
eliminate lack of spark as a probable cause.

--
Jeff Liebermann * *
150 Felker St #D * *http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann * * AE6KS * *831-336-2558

I have eliminated an internally arcing spark plug as a possibility
because I tried sticking a screw driver into the boot and acing it to
ground and there was no spark with that method. In addition, with the
shroud (with the starter pull rope) removed, and turning the engine
with a drill the high voltage wire is well removed from chassis ground
so it arcing is not the problem either. However now I think that I
know what may have happened. I ran across the sites below that had
really good writeups on small engine ignition theory. The second one
happened to mention that you should never fire an ignition coil with
the secondary disconnected from the spark plug or as they put it a
"suitable load". The article went on to say that doing so could cause
internal acing in the coil and damage it. I never knew this but it
makes sense and incidentally adds up as well. I happened to mention
this to my son this morning and he admitted that during the course of
his working on the engine when he had it running for a few seconds and
then it would die he had done this very thing. And mysteriously now we
have no spark where he did before. So a new coil is about twenty five
dollars and I'm thinking that should hopefully take us back to square
one where we should be back to the two second run problem, (I hope).
If I knew that it was just the coil I guess I'd spring for the twenty
five
bucks plus freight. However given the history with this engine I'd
rather not go throwing a lot of money at something that may need a
carburetor or more as well. I gotta go see the used lawn mower guys
this week and hopefully find a coil. Lenny

klem kedidelhopper wrote:
... you should never fire an ignition coil with
the secondary disconnected from the spark plug or as they put it a
"suitable load". The article went on to say that doing so could cause
internal acing in the coil and damage it. ...

Although that sounds plausible, I'm skeptical. First, I don't see how
an internal spark would happen. I.e., what the path would be. But even
if it could, I've fired disconnected coils lots of times without problems.

An alternative explanation would be that the coil was marginal at the
start - good enough to run for the few seconds. Then failed altogether.
I don't know if there is a coil failure mode like that, but I wouldn't
rule it out.

Bob

... you should never fire an ignition coil with the secondary
disconnected from the spark plug, or as they put it a "suitable
load". The article went on to say that doing so could cause
internal acing in the coil and damage it. ...

Although that sounds plausible, I'm skeptical. First, I don't see
how an internal spark would happen, ie, what the path would be.
But even if it could, I've fired disconnected coils lots of times
without problems.

And how is external arcing "somewhere else" different from arcing
across the spark plug's gap?

On Thu, 6 Sep 2012 06:18:03 -0700, "William Sommerwerck"
wrote:

... you should never fire an ignition coil with the secondary
disconnected from the spark plug, or as they put it a "suitable
load". The article went on to say that doing so could cause
internal acing in the coil and damage it. ...

Although that sounds plausible, I'm skeptical. First, I don't see
how an internal spark would happen, ie, what the path would be.
But even if it could, I've fired disconnected coils lots of times
without problems.

And how is external arcing "somewhere else" different from arcing
across the spark plug's gap?

When the coil creates a high voltage, there will be an arc wherever
the gap is the smallest. That is supposed to be the spark plug. If
the plug isn't there, it could arc inside the coil and thereby
destroying some high voltage insulation. It is possible that from
then on, the shortest gap is inside the coil. I am not saying that is
what happened - just explaining what the warning meant.

Pat wrote:
When the coil creates a high voltage, there will be an arc wherever
the gap is the smallest. ... it could arc inside the coil and thereby
destroying some high voltage insulation. ...

You're right, but there are limitations. First, the voltage isn't
unlimited, it has some maximum, whether there's a gap or not. I don't
know the mechanisms limiting it - parasitic capacitance, leakage
current, I dunno. Hopefully the coil designer knew and insulated
against it, maybe.

Then there's the path of an internal arc. There's certainly not enough
voltage for an arc between adjacent turns. Also very unlikely between
adjacent layers. The highest voltage is between the last turn and the
core. But that's the most heavily insulated path.

I'd be convinced by an actual case of an internal arc - anybody ever see
one?

Bob

On Thu, 6 Sep 2012 05:08:32 -0700 (PDT), klem kedidelhopper
wrote:

The second one
happened to mention that you should never fire an ignition coil with
the secondary disconnected from the spark plug or as they put it a
"suitable load". The article went on to say that doing so could cause
internal acing in the coil and damage it. I never knew this but it
makes sense and incidentally adds up as well. I happened to mention
this to my son this morning and he admitted that during the course of
his working on the engine when he had it running for a few seconds and
then it would die he had done this very thing.

90% baloney as usual. There are two ways to "run" an engine without a
load on the ignition coil.

One is to hand start the engine with the spark plug wire disconnected.
That won't do any damage as there's not enough energy in the spark
from hand cranking to do any damage.

The other way is to run the engine for a while, and remove the spark
plug wire. Assuming you can do this without getting a nasty shock, it
might internally arc across the coil. However, in my limited
experience with chain saws and small generator engines, a shorted coil
will still generate a small arc. Not a hot or big as a normal coil,
but unless the short is somehow across the entire coil (easily found
with an ohmmeter test), you'll still see a tiny spark. Buy a real
tester:
http://www.ebay.com/sch/i.html?_trksid=p5197.m570.l1313&_nkw=spark+plug+te ster
(I made my own spark gap from a piece of U shaped plastic).

What I think happened here is that someone transplanted the story from
their automobile or multi-cylinder engine experience. With more than
one cyclinder, it is possible to run the engine with one spark plug
wire disconnected, which might cause internal arcing. However, it's
not likely with a single cylinder engine.

Note that the coil part number that I excavated is used in Husqvarna,
Tecumseh, Toro, and others. If it was as failure prone when NOT
running as you imply, there would be recalls and other failures in
epidemic numbers.

Testing the ignition:
http://www.youtube.com/watch?v=MNvwZmZj610

This one covers most ways to test your engine spark.
http://www.youtube.com/watch?v=5qSgmunp_Ys

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

"Bob Engelhardt" wrote in message
...
Pat wrote:
I'd be convinced by an actual case of an internal arc - anybody ever see
one?

Bob

Yes. Many. Thats how they fail. Temperature, vibration, aging induce small
cracks in the insulation. Dirt, moisture infiltrate, etc. Better coils are
designed with internal aux gaps greater than the normal spark plug gap. I've
dissected failed coils, not hard to find traces of internal arcing, melting.

Bob Engelhardt wrote:



I'd be convinced by an actual case of an internal arc - anybody ever see
one?
Well, I had a B&S engine that would run for 10 minutes or so, and then
get weak, sputter and finally die. if you let it sit for a couple
minutes, it would start and run for 30 seconds or so and die again.
A new spark coil fixed it completely, and it ran fine until the deck,
wheel drive, etc. was completely worn out.

Just had a problem with its replacement mower. it would run for about
20 minutes, start knocking, lose power and then die with a big blast of
oil smoke, I guess it got hot enough to boil the oil out the crankcase
vent, and sucked that into the carb. I cleaned the cooling passages,
but that didn't help. It finally occurred to me the timing could be off,
so I checked the shearable key on the flywheel, and it was sheared.
I haven't run it for 20 minutes yet, but I'll be that was the problem,
advanced spark timing. It does seem to run better though, I'll put the kids
to work soon for a more exhaustive test of my repair.

Jon

Replace the coil and be done
Jerry

On Fri, 27 Feb 2015 09:08:17 -0800 (PST), wrote:

Replace the coil and be done
Jerry

HUH? I don't even own a Toro self propelled lawn mower!

Oh, I see... Another google grooper...