Ignition coil failure on old 14hp Kohler

Scott Willing · 2005-08-02T19:12:21+00:00

Last time I tried posting here, the msg never showed up, so this issomething of a test as well as a genuine request.I bought an old Case garden tractor last year. My neighbor, afarmer/logger/machinist had rebuilt the engine. This old unit hasbattery ignition, i.e. coil and points, with a generator/starter.It used to die on occasion after a stretch of especially hard work.Let it cool off for a few hours and it would go again. But this yearone day it died for good.After finding no spark, I measured the coil with a meter anddiscovered the primary winding was open. Got a new coil (along withpoints, condensor and plug) and tried the measurement with the new onejust for future reference just to make sure I knew what I was doing.Measuring the "points" terminal to the +12 terminal I saw the primarycoil resistance, and between "points" and HT terminal, there was thesecondary coil resistance. (I believe this coil may also include aresistor in the primary, but I don't know that for certain.)I got it all back together, used it several times and it was runninglike a dream, never better. Then the other day, again after a stretchof particularly hard work (but certainly not the first on the newparts) wound up close to max rpm, it died.Lo and behold, the primary winding has gone open on the brand newcoil(!) Just bad luck to get a bum coil, coincidence that the old onefailed? The guy who supplied it is going to exchange it for me but Igotta wonder if there's a coil-eating problem in this machine. There's not much else I can think of to suspect except the oldmechanical voltage regulator (and no, unfortunately, I never checkedvoltage while running but I surely will). But two experienced repairguys assure me that there is no way, even if the coil was getting fullunregulated voltage, that it should fail. I'm not so sure.Other opinions? It's a two-hour drive to pick up a replacement coil,and I'm not keen to repeat this exercise this year if I can help it.Would you replace the old...

Aug 02, 2005 22 Replies

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Chris Lewis 20 years ago

According to Scott Willing :

I glanced at the pages, it's all about cleaning the contacts and setting gaps (both gaps are supposed to be .020). The regulation voltage is supposed to be set at 14V.

I should think. One day I should read up on them more.

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(This is for a jeep, the Cub has two relays, not three).

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Randy hitt 8 years ago

replying to Scott Willing, Randy hitt wrote: Add a resister in hot wire going to coil and use any 12 volt coil and problems are fix

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Randy hitt 8 years ago

replying to Scott Willing, Randy hitt wrote: Add a resister in hot wire going to coil and use any 12 volt coil and problems are fix

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