Kohler 8HP No spark

[N.C. horserider 5]

1972 Commando 800 4 speed I'm getting no spark to plug on K181S spec# 30461D Serial # 4089559

The motor turns over but with plug out resting on head there is no spark. Tried another coil and condenser still nothing. Checked points and they are at .020 no corrosion. Battery is new and all connections are tight. Any ideas what may be causing this ?

[W9JAB 156]

:thumbs: A bad plug and or wire, is all that's left :thumbs2:

[Buzz 502]

Are you getting 12 volts to the (+) side of the coil with the key on? Use a test light hooked to a good ground and touch the tip to the (+) side of the battery to make sure the bulb is good . Turn the key on and touch the (+) side of the coil. It should light. If it doesn't then the problem is most likely in the wire or the ignition switch. If it lights touch the tip to the (-) side of the coil and crank the engine over. The light should blink off and on as the points open and close. If they don't open and close the are either gapped way off or the point pushrod is worn or broken. Do you have a new plug or other coil wire you could try?

[N.C. horserider 5]

This is the second coil and I'm using the plug and wire out of my running K341 so I don't think the plug or plug wire is the problem. I'll try checking the coil wires with test light.

[oldandred 15]

Clean the points and make sure the engine is grounded

[N.C. horserider 5]

Thanks for the help Buzz when I checked the positive terminal on the coil it did not light when the key was on. I put the light right to the ignition switch contact for that wire and it is dead so I will get another ignition switch tomorrow and give that a try and post back again thanks for the assistance !! Mike

[N.C. horserider 5]

I put in another switch and the same thing is happening no power to coil. I was checking the wires to the diagram and they don't seem to coincide. WhenI took the tape off of the harness this how I found it. I'm trying eliminate where somebody cut all these wires and make it right. Here are pictures of the wiring and the diagram. Which wire should go to which terminal on the switch.

[TT-(Moderator) 1,127]

If the "drawing" you posted is of the current ignition switch terminals, then that's problem #1.

You need an ignition switch for battery ignition, which is Toro P/N 103990 or Stens # 430-512. You might as well get a new pigtail for the switch while you're at it. (Stens #430-223)

Once you get the correct switch, follow the schematic you have posted and give a shout if you need help with it.

As for the current wiring...... tear it all off but the battery cables and start over. :thumbs2:

[N.C. horserider 5]

Here is the digram of electrical system. I have put on all new wires and ran them from each location. The only thing changed was I did not hook in the clutch switch.

I hooked all the wires to the plug like diagram shows for ignition switch (103990) and when I turn the key to run it starts cranking. I might have the wires in the plug wrong as it is hard to see on the 800 diagram. I have tried both ways with same result. Any solutions to this welcome, Thanks Mike

Attached Image (Click thumbnail to expand)

[TT-(Moderator) 1,127]

Here's the diagram for the back of the 103990 switch:

"A" is for accessory and can be used to power lights, electric PTO clutches, etc.

"R" is for the wire from the "B+" terminal on the rectifier/regulator.

"I" feeds the "+" terminal on the ignition coil.

"B" is for the power feeding the switch - normally feeds from the battery side of the solenoid. (would "pass through" the ammeter if equipped)

"S" is for the small "trigger" terminal on the starter solenoid.

If any terminal on your current switch has continuity between it and the metal switch housing in any key position, it is the wrong switch.