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Andy Asberry
Guest
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 Posted: Mon May 30, 2005 6:04 am Post subject: Semi OT: Testing Kohler engine coil |
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Single cylinder Kohler engine. Magneto ignition. Ran fine. Next time I
tried to start it, no spark. I've replaced/checked everything except
the coil; plug, points, condenser, disconnected kill wire, cleaned
flywheel magnet and coil poles. I really don't want to remove the
coil if I don't have to. The way the wires are routed, I would have to
remove the engine side plate.
I'm looking for a homebrew way to test the coil. |
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Lane
Guest
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| Posted: Mon May 30, 2005 7:01 am Post subject: Re: Semi OT: Testing Kohler engine coil |
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"Andy Asberry" <andyasberry@earthlink.net> wrote in message
news:3t7l91hubh756t8294eh384bob5g4fl6p2@4ax.com...
| Quote: | Single cylinder Kohler engine. Magneto ignition. Ran fine. Next time I
tried to start it, no spark. I've replaced/checked everything except
the coil; plug, points, condenser, disconnected kill wire, cleaned
flywheel magnet and coil poles. I really don't want to remove the
coil if I don't have to. The way the wires are routed, I would have to
remove the engine side plate.
I'm looking for a homebrew way to test the coil.
|
I can't tell from your post if you replaced the condenser or just "checked
it". But I'll tell you to go ahead and replace it. I had the same problem as
you. Plus, the condenser is a heck of a lot cheaper and it was the fix for
my 17 HP Kohler engine.
Lane |
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jim rozen
Guest
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| Posted: Mon May 30, 2005 3:02 pm Post subject: Re: Semi OT: Testing Kohler engine coil |
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In article <3t7l91hubh756t8294eh384bob5g4fl6p2@4ax.com>, Andy Asberry says...
| Quote: | I'm looking for a homebrew way to test the coil.
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Most of the ways I'd test it involve removing it so you
can gain access to all the electrical terminals on it.
Mag coils often (not always though) fail when they
come up to operating temperature. Basically they'll
pretty much start the motor when it's cold, but
once it's warmed up the coil will either fail to
maintain engine operation, or if it it's shut off
it will not allow a re-start without cooling off
first.
If this is the case then the coil insulation has become
lossy and is shunting HT current to ground.
Coils do sometimes fail dead all at once, but that is
frequently a wire in the coil that's gone open.
Jim
--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
================================================== |
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Lloyd E. Sponenburgh
Guest
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| Posted: Mon May 30, 2005 3:02 pm Post subject: Re: Semi OT: Testing Kohler engine coil |
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"jim rozen" <jim_member@newsguy.com> wrote in message
news:d7f7qi0k86@drn.newsguy.com...
| Quote: | Mag coils often (not always though) fail when they
come up to operating temperature. Basically they'll
pretty much start the motor when it's cold, but
once it's warmed up the coil will either fail to
maintain engine operation, or if it it's shut off
it will not allow a re-start without cooling off
first.
|
Yup. I had a situation with an _old_ Dayton generator with the 8-horse cast
iron Briggs with an updraft carb. The coil was doing just as you said.
For whatever reason, the Briggs shops around said the coil was special,
scarce, and expensive. I thought they were all the same; but no. Since it
was an emergency generator, I didn't want to have to special order parts if
they failed.
So, we tapped off the battery charger terminals for a DC supply, and hooked
up a common 12V automotive coil, along with a suitable ballast resistor.
Ran it through the points and capacitor, just like normal. Interestingly,
we didn't have to change the cap... it worked fine with either a coil or
mag.
The only inconvenience is that it's nigh impossible to pull-start the beast,
now. You pretty much have to battery start it to get the DC supply going
enough to power the coil.
This is a late-50's gen-set, and it runs as well as the day it was born.
Dual-fuel, too! You start it on gas, then can switch to kerosene or #2 fuel
oil (with a drop in horsepower).
LLoyd |
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jim rozen
Guest
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| Posted: Mon May 30, 2005 5:02 pm Post subject: Re: Semi OT: Testing Kohler engine coil |
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In article <ZRFme.87544$IO.29086@tornado.tampabay.rr.com>, Lloyd E. Sponenburgh
says...
| Quote: |
"jim rozen" <jim_member@newsguy.com> wrote in message
news:d7f7qi0k86@drn.newsguy.com...
Mag coils often (not always though) fail when they
come up to operating temperature. Basically they'll
pretty much start the motor when it's cold, but
once it's warmed up the coil will either fail to
maintain engine operation, or if it it's shut off
it will not allow a re-start without cooling off
first.
Yup. I had a situation with an _old_ Dayton generator with the 8-horse cast
iron Briggs with an updraft carb. The coil was doing just as you said.
|
The deal is that insulation gets worse when it gets hot. One way
to check this with absolute finality is to do a megger test on a coil,
on the bench. Meggers are high voltage (hand cranked generator) test
instruments that will read resistance in the tens of thousands of
megohms.
The megger leads are connected to the coil armature (laminations)
and the HT lead. If an acceptable insulation resistance is obtained,
the next step is to gently heat the coil with a heat gun, and
repeat the test. A coil with much below 100 megohms isolation
won't reliable start a motor.
Jim
--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
================================================== |
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Winston
Guest
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| Posted: Tue May 31, 2005 4:05 am Post subject: Re: Semi OT: Testing Kohler engine coil |
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Andy Asberry wrote:
| Quote: | Single cylinder Kohler engine. Magneto ignition. Ran fine. Next time I
tried to start it, no spark. I've replaced/checked everything except
the coil; plug, points, condenser, disconnected kill wire, cleaned
flywheel magnet and coil poles. I really don't want to remove the
coil if I don't have to. The way the wires are routed, I would have to
remove the engine side plate.
I'm looking for a homebrew way to test the coil.
|
Bailing wire.
Unscrew Mr. Sparkplug and reattach the High Tension lead as per normal.
Use a length of bailing wire to attach the spark plug to the head of your
engine, away from the hole the sparkplug normally lives within.
Give her a couple good pulls and watch for the blue spark in the
sparkplug gap.
--Len |
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Ken Davey
Guest
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| Posted: Tue May 31, 2005 5:02 am Post subject: Re: Semi OT: Testing Kohler engine coil |
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Winston wrote:
| Quote: | Andy Asberry wrote:
Single cylinder Kohler engine. Magneto ignition. Ran fine. Next time
I tried to start it, no spark. I've replaced/checked everything
except the coil; plug, points, condenser, disconnected kill wire,
cleaned flywheel magnet and coil poles. I really don't want to
remove the coil if I don't have to. The way the wires are routed, I would
have
to remove the engine side plate.
I'm looking for a homebrew way to test the coil.
Bailing wire.
Unscrew Mr. Sparkplug and reattach the High Tension lead as per
normal. Use a length of bailing wire to attach the spark plug to the
head of your engine, away from the hole the sparkplug normally lives
within.
Give her a couple good pulls and watch for the blue spark in the
sparkplug gap.
--Len
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Or - you could plunk down a couple hundred dollars for a non-contact sensor
that gives a readout of the voltage in the spark plug lead as you crank it.
http://tinyurl.com/co24e to point out just one.
Or, if you really want to go 'uptown
http://tinyurl.com/cthm8
I actually have this one and it does come in handy troubleshooting multi
cylinder outboard motors.
Neat toys but the baling/mechanic's wire is by far the preferred method for
a go/no go test.. |
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Gunner
Guest
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| Posted: Tue May 31, 2005 11:02 am Post subject: Re: Semi OT: Testing Kohler engine coil |
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On Mon, 30 May 2005 21:08:56 -0700, "Ken Davey"
<PGJSCAYQVANK@spammotel.com> wrote:
| Quote: | Winston wrote:
Andy Asberry wrote:
Single cylinder Kohler engine. Magneto ignition. Ran fine. Next time
I tried to start it, no spark. I've replaced/checked everything
except the coil; plug, points, condenser, disconnected kill wire,
cleaned flywheel magnet and coil poles. I really don't want to
remove the coil if I don't have to. The way the wires are routed, I would
have
to remove the engine side plate.
I'm looking for a homebrew way to test the coil.
Bailing wire.
Unscrew Mr. Sparkplug and reattach the High Tension lead as per
normal. Use a length of bailing wire to attach the spark plug to the
head of your engine, away from the hole the sparkplug normally lives
within.
Give her a couple good pulls and watch for the blue spark in the
sparkplug gap.
--Len
Or - you could plunk down a couple hundred dollars for a non-contact sensor
that gives a readout of the voltage in the spark plug lead as you crank it.
http://tinyurl.com/co24e to point out just one.
Or, if you really want to go 'uptown
http://tinyurl.com/cthm8
I actually have this one and it does come in handy troubleshooting multi
cylinder outboard motors.
Neat toys but the baling/mechanic's wire is by far the preferred method for
a go/no go test..
|
Or you could have your kid hold the end of the wire....
This generally only works once though....
Gunner
"Considering the events of recent years,
the world has a long way to go to regain
its credibility and reputation with the US."
unknown |
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JohnM
Guest
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| Posted: Tue May 31, 2005 6:02 pm Post subject: Re: Semi OT: Testing Kohler engine coil |
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Gunner wrote:
| Quote: |
Or you could have your kid hold the end of the wire....
This generally only works once though....
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I used to know an old guy who repaired lawnmowers- that was his
preferred method. He'd grab the wire and turn the flywheel by hand, once
in a while he'd jump and say "That's a really good one".
I told the story here before, about my kids with a telephone generator.
They'd have a friend over and it didn't take long before I'd hear "Here,
touch it again.." "NO! You touch the stupid thing."
| Quote: |
Gunner
"Considering the events of recent years,
the world has a long way to go to regain
its credibility and reputation with the US."
unknown |
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Winston
Guest
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| Posted: Wed Jun 01, 2005 2:02 am Post subject: Re: Semi OT: Testing Kohler engine coil |
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Gunner wrote:
| Quote: | Or you could have your kid hold the end of the wire....
This generally only works once though....
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Unfortunately it works at least twice.
Guess who gets to be the next 'sparkplug'?
Yiiiii!
--Winston |
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Winston
Guest
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| Posted: Wed Jun 01, 2005 2:02 am Post subject: Re: Semi OT: Testing Kohler engine coil |
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Ken Davey wrote:
| Quote: | Or - you could plunk down a couple hundred dollars for a non-contact sensor
that gives a readout of the voltage in the spark plug lead as you crank it.
http://tinyurl.com/co24e to point out just one.
Or, if you really want to go 'uptown
http://tinyurl.com/cthm8
I actually have this one and it does come in handy troubleshooting multi
cylinder outboard motors.
|
Dammit Ken, don't *show* me stuff like that. :)
Ya trying to make this recovering toolaholic fall off the wagon (again)?
Very nifty.
--Winston |
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Leo Lichtman
Guest
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| Posted: Mon Jun 06, 2005 5:02 am Post subject: Re: Semi OT: Testing Kohler engine coil |
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"Winston" wrote: (clip) Use a length of bailing wire to attach the spark
plug to the head of your engine, away from the hole the sparkplug normally
lives within. Give her a couple good pulls and watch for the blue spark in
the sparkplug gap.
^^^^^^^^^^^^^^^^
That will tell you whether you have spark, but if there is none, it could be
the coil, or something else--such as points, condenser, a loose or broken
wire, or a grounded wire. It could even be a badly sooted spark plug
bleeding the spark to ground.
So, I think the OP's original question still needs to be answered: Is there
a way to test the coil itself? |
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J. R. Carroll
Guest
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| Posted: Mon Jun 06, 2005 6:02 am Post subject: Re: Semi OT: Testing Kohler engine coil |
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"Leo Lichtman" <l.lichtman@worldnet.att.net> wrote in message
news:qKQoe.289463$cg1.209856@bgtnsc04-news.ops.worldnet.att.net...
| Quote: |
"Winston" wrote: (clip) Use a length of bailing wire to attach the spark
plug to the head of your engine, away from the hole the sparkplug normally
lives within. Give her a couple good pulls and watch for the blue spark in
the sparkplug gap.
^^^^^^^^^^^^^^^^
That will tell you whether you have spark, but if there is none, it could
be
the coil, or something else--such as points, condenser, a loose or broken
wire, or a grounded wire. It could even be a badly sooted spark plug
bleeding the spark to ground.
So, I think the OP's original question still needs to be answered: Is
there
a way to test the coil itself?
|
Remove the coil wire connection to the distributor cap and hold the end near
a ground while you crank the engine.
--
John R. Carroll
Machining Solution Software, Inc.
Los Angeles San Francisco
www.machiningsolution.com |
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Mike Fields
Guest
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| Posted: Tue Jun 07, 2005 2:02 am Post subject: Re: Semi OT: Testing Kohler engine coil |
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"J. R. Carroll" <jcarroll@machiningsolution.com> wrote in message
news:QNQoe.401$bv7.99@newssvr21.news.prodigy.com...
| Quote: |
Remove the coil wire connection to the distributor cap and hold the end
near
a ground while you crank the engine.
--
John R. Carroll
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No thanks, YOU hold it near a ground and I will crank the
engine. If I see the spark OR you jump, I will know the coil
is working. Been hit by a healthy spark coil before. Once is
enough thanks !!
mikey |
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