Kohler 321 no spark at coil

[Simplecity 22]

Good Day All

   I acquired a 312 Kohler in a 'Green' tractor that was part of the deal to obtain the 857 that I really wanted.

   My goal is to send the green tractor down the road as quickly (cheaply) as possible.

   After cleaning the fuel system, replacing the fuel filter filled with some new gas, it cranked like there was rocks in the starter.

   Long story short, the permanent magnets in the starter had cracked and were being ground up by the commutator. $50 later I had a rebuilt starter that you have to physically raise the motor to replace (thank God I have a cherry picker).

  Motor now cranks with authority and with a little coaxing if fired up (first time in over 2 years) and ran decently. A trip around the 'estate' showed a couple of other gremlins that needed exorcising. I pulled back in the shop and as I was idling down the tractor died. Since then (yesterday afternoon) I have no spark at the coil.

 I can get spark at the points with a screwdriver but that is all. I have tried three different coils and condensers, pulled the ignition switch (5 terminal) cleaned the spades and checked it with a VOM. All terminals work as they should with the exception of the accessory (lights) terminals. Checked the continuity of the wires to the coil, all is well. This tractor appears to have been  'rode hard a put away wet' with minimal maintenance being performed through the years.  

  A couple of basic electrical questions:

 1) With the key 'on' should I have power at the '+' side of the coil?

 2) Could someone shed some light on how to check a coil with a VOM?

As I'm typing this it occurred to me that the safety switch(s) are long gone,  If one of them grounded out, would that explain the loss of power?

 Thanks to All who respond.

  Thank a Vet this Memorial Day weekend.

    Simplecity        

[wallfish 16,994]

Yes, 12v at the + side of the coil with the key in RUN and the START positions

Doubtful it's a bad coil since you tried others as well. Condenser on the - side with the points.

 

Loose or bad ground maybe? You can bypass all wiring with a temp wire from the + battery to the + coil for testing purposes

 

[WHX?? 48,814]

Yoi didn't mention it but guessing you checked the plug & wire? 

[squonk 41,067]

Spark at points with the screwdriver indicates at least you have power from the switch to and through the coil. Have you cranked the engine with the points cover off to make sure the points are moving? Could be the gap adjustment is off and the points aren't opening enough to break the circuit . 

 

[gwest_ca-(File Mod) 11,040]

Key in RUN or START

Remove the spark plug so you can turn the engine over by hand.

Voltage at the coil (-) should be battery voltage when the points are open.

Voltage at the coil (-) should be 0 volts when the points are closed.

It is this on-off cycle that causes the coil to fire.

 

[953 nut 55,188]

Here are a couple of drawings from @Save Old Iron that will help you check those coils.

 

[wallfish 16,994]

1 hour ago, 953 nut said:

Here are a couple of drawings from @Save Old Iron that will help you check those coils.

Miss SOI as he always had solid, practical and non-complicated advice on all electrical stuff.

I don't care if he didn't have any tractors.

[WHX?? 48,814]