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qualityhardware Member
Joined: Apr 01, 2006 Posts: 52
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Posted: Fri Nov 24, 2006 11:42 am Post subject: Testing an ignition coil - M170 |
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Had my M170 running the other day pretty well. Set the timing and tripled checked the condenser points for .020" gap on the high edge of the rotor cam and she ran great...for a day.
I am now not getting spark. Pulled the #1 wire and plug from the block and observed no spark from the plug while cranking.
I pulled the cap from the distributor and observed the condenser points while cranking.
The ignition coil threw a single spark from the positive terminal and the condenser points sparked twice and that was it.
I pulled the primary cable from the coil and grounded it with the ignition switch "on". Got one $&% of a spark - which according to the manual, means the capacitor and cable to the capacitor are A-OK.
Does this mean my coil is bad? If yes, what's the best way to test it?
Thanks... |
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OKCM38CDN Guest
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Posted: Fri Nov 24, 2006 4:18 pm Post subject: |
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Is your coil one of the cheap ones from China maybe...?
I got one of those and it ran for about a day then blew the top off the coil...
I found an older American made one at aswap meet and have not had problems since... Might try John Bizal at Midwest Military or Frank's Surplus in PA... Most any coil for a 24v system should work... look for something from an M151, M-38A1 or such...
Hope this helps... |
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wesk Site Administrator
Joined: Apr 04, 2005 Posts: 16256 Location: Wisconsin
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Posted: Fri Nov 24, 2006 10:02 pm Post subject: |
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Not sure which manual you are referring to. If you get a good hot spark then your coil is producing. I would take a long hard look at the system trigger. and it's guard. The points and the condenser.
Hook all like it's suppose to be and leave the condenser disconnected and turn rotor to close the points. Now turn on the ignition and with a plastic or wood probe open the points and the coil should produce a spark. If it does you need a new condenser. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Mjeeps photo album: http://www.willysmjeeps.com/v2/modules.php?set_albumName=Wes-Knettle&op=modload&name=gallery&file=index&include=view_album.php |
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qualityhardware Member
Joined: Apr 01, 2006 Posts: 52
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Posted: Sat Nov 25, 2006 9:38 am Post subject: |
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Thanks Wes,
I am using TM 9-8014 for the M38A1 and M170.
I did as you advised. Popped the top off the distributor and rotated the points until closed.
Turned on the ignition switch and opened the points with a chopstick.
Spark was really weak and intermittent. Every now and then, the (+) terminal on the coil would throw a big spark.
I doubled checked the points gap to .020" and then turned the motor. Got a consistent but weak spark.
As a final check, I put the top back on the distributor and tried cranking - even with a dose of ether in the carb. Nothing. Sounds like the spark is too weak to cause spark at the plugs.
So this would mean I need new condenser points? |
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wesk Site Administrator
Joined: Apr 04, 2005 Posts: 16256 Location: Wisconsin
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qualityhardware Member
Joined: Apr 01, 2006 Posts: 52
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Posted: Sun Nov 26, 2006 12:48 am Post subject: |
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Hi Wes,
I appreciate it. Digital VOM and Ohm readings is out of my league. Looks like the coil replacement is where I need to go... |
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steveh Member
Joined: Nov 10, 2006 Posts: 31 Location: Somerset, Ohio
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Posted: Thu Dec 07, 2006 5:54 am Post subject: |
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I was just reviewing older message and ran across this one. I would be interested in Ohm values for the coil on my M38 - serial number 61702, motor number 72685, distributor number AXS 1851, Ord numbr 7355596, serial number 2F108673.
Thanks
Steve H
Somerset, OH |
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wesk Site Administrator
Joined: Apr 04, 2005 Posts: 16256 Location: Wisconsin
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qualityhardware Member
Joined: Apr 01, 2006 Posts: 52
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Posted: Fri Dec 08, 2006 7:23 am Post subject: |
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Wes,
YOU ARE THE MAN.
Thanks. |
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charlesfitton Member
Joined: Jun 07, 2010 Posts: 69 Location: Maryhill On
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Posted: Wed Jun 01, 2016 3:04 pm Post subject: |
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TM9 1825B? _________________ M38 CDN 52-30105
M38 CDN 52-30883
and other green crap... |
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wesk Site Administrator
Joined: Apr 04, 2005 Posts: 16256 Location: Wisconsin
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charlesfitton Member
Joined: Jun 07, 2010 Posts: 69 Location: Maryhill On
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Posted: Thu Jun 02, 2016 3:59 am Post subject: |
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Excellent - I can't find these in the downloads section. _________________ M38 CDN 52-30105
M38 CDN 52-30883
and other green crap... |
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4x4M38 Member
Joined: May 30, 2014 Posts: 3447 Location: Texas Hill Country
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wesk Site Administrator
Joined: Apr 04, 2005 Posts: 16256 Location: Wisconsin
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