[Mike Halliday]

Just fitted a new ignition on a machine I've put together it works fine but I can't turn the machine off

I have to turn down the revs and stall it to Stop it running

All it has is a earth to the switch, then a live wire to the battery and a live to the starter motor, I sure there is a wire missing that cuts out the engine but this engine came with no wiring.

Any ideas how to stop it?

[Kenny83]

i'm not familiar with Kohlers, but usually the switch has an an earth / metal plate on it that earths the spark out when turning the switch to stop position, therefore maybe the part on the switch isn't touching the engine / cowling (wherever it's located)
All's a switch does on a petrol is take the spark away from the plug to stop the engine, thinking of this rule may help you with your problem.
Hope this helps?
in the meantime you could cut the earth from the switch and just touch the engine block while running it, then connect back up when you fix the problem at a later date? or maybe you could run a wire directly from the off position on your switch straight to your engine block or ground?

[Mike Halliday]

Thanks that's a help,

 I think it is a grounding problem, the ignition switch is just hanging free I might ground it against the machine to see if it has an effect. If it cannot be resolved I might just fit a fuel cut off and starve it until it stops

[Kenny83]

Hi, if it'd just hanging free then it's definitely that whats causing your problem mate, have a look behind it for some kind of metal element or loose wire, then connect it to ground.
Cheers
 

[BDCS]

There could be a wire on the coil pack that is earthed through the switch on the zero position - check this if earthing the switch fails