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Subject: Trouble shooting help

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AL CT    Posted 07-13-2019 at 09:48:33 [URL] [DELETE]        [Reply] [Email]  
  • Trouble shooting help
  • I have a 1944 2N front mount distributor. Pulled the tractor from the barn recently to start it. Tested spark with the spark plug test, laying head and looking for spark. How does one test the coil? I have a good switch. I searched the How To section and can't find a trouble shooting section. Email is open, please help. I don't want to just throw parts on something that could be a minor repair.

    Bruce (VA)    Posted 07-13-2019 at 12:47:05 [URL] [DELETE]        [Reply] [Email]  
  • Re: Trouble shooting help
  • Coil problems are difficult to diagnose. For starters, round coils are pretty robust & square coils arenít (because of the difference in insulation used), but neither one will hold up to a poorly done 12v conversion that allows too much current to the coil or leaving the key on (see tip # 38). Too much current creates heat which melts the insulation. Insufficient resistance in a 12v conversion will do the same thing. Rarely do coils just ďgo bad.Ē

    As others have said, there are a few ways to see if a coil is bad, but itís not possible to determine if a coil is good w/o some expensive testing equipment. If you detect a dead short or high resistance in the coil w/ an ohm meter, itís bad. If itís cracked, itís bad. If a sidemount coil w/ battery voltage to the primary will not jump a ľĒ gap from the secondary wire to the block, itís bad. But, here is the hard part: even if you do not detect a short, even if it will produce a spark, even if itís not cracked, that doesnít mean the coil will work when itís hot & under a load. So, itís a process of elimination. If the tractor starts & runs fine for 30 minutes or an hour then cuts off & refuses to re-start, and you checked for spark at the plugs & it had no spark at all, AND you have the correct voltage at the coil thatís a good sign that you have a bad coil. Let it cool off, restart it & if you have a good spark, odds are itís a bad coil. But, even then, you might end up w/ a spare coil on the shelf!

    Bottom line.......coils do go bad, but I'll venture a guess that 75% of new N coils sold today are sold to folks who do not understand how to diagnose a poor spark problem or how a coil works. So, for those who donít know any better, in a no spark situation the first suspect is usually the coilÖÖand, more often than not, it isnít the problem.

    Or as one regular around here humorously suggested: "Well, it is like this...I don't know or really understand what that black thing does & I am suspicious of the unknown, so I think the problem is the black thing."

    So, what problem are you having that leads you to suspect a coil failure?

    AL CT    Posted 07-13-2019 at 13:40:04 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Trouble shooting help
  • I took a used spark plug and spread the electrode to 3/16" ,laid the plug on the head. Switch on, cranked the starter. No spark. Checked the point gap, made sure it was .016-.018". I've worked on tractors and cars that have round coils. Easy to diagnose. Square coils not so much. Original 6 volt system.

    Richard NY 2N    Posted 07-13-2019 at 15:59:06 [URL] [DELETE]        [Reply] [Email]  
  • Re: Trouble shooting help
  • I didn't spark on my 45 2n. Swapped a rebuilt distributor, and still no spark. So I started testing things and found the key switch bad.Just my situation.

    AL CT    Posted 07-13-2019 at 17:07:09 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Trouble shooting help
  • I also found the original switch was defective. Swapped it our for a new (tested) switch. Same lack of spark. I'm going to pull the distributor in the next day or two. Start there.

    Richard NY 2N    Posted 07-14-2019 at 07:42:58 [URL] [DELETE]        [Reply] [Email]  
  • Re: Trouble shooting help
  • You could do some voltage tests before removing the distributor.

    Jon Rhee (RI)    Posted 07-14-2019 at 17:11:12 [URL] [DELETE]        [Reply] [Email]  
  • Re: Trouble shooting help
  • Our tractors must have caught some kind of virus. My Jacobsen ( Ford 192) had a slight intermittent miss a couple weeks ago which degraded into a very prominent miss resulting in a no start, or rough start and quit status. Iíve been going through both carburetor and ignition all week - cant figure it out yet. Iíve swapped everything.... now considering the switch and wiring. Ugh.

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