I Have an older Craftsman 10 HP 30" rear engine riding mower. The mower starts and stops fine when the mower is cold, but after a few minutes running, the mower will not cut off (either by Ignition switch or by safety cutoff).
The mower will cut off fine until its been running for about 3-5 minutes.
I have replaced the ignition switch (No effect)
I have measured the ohms from the kill wire to ground and it is not grounded when the mower isn't able to stop normally.
I am thinking it may be a bad system ground (but the system ground is 8 inches from the engine, why would running 5 minutes make the ground fail???)
I have torn the mower apart and tested all the safety switches and wiring, and I can find no switches that don't work nor any skinned or broken wires.
Any advice would be welcome.
Take the cover off the engine and trace the thin black wire back to the plug.
Unplug it and test the mower side for continuity to earth with the ignition in both the on & off position.
This wire kills the ignition by going to earth.
Start the engine and try it both hot & cold,
If it still does not shut off, check the wire for a break between this plug & the coil..
If it shuts down properly then the problem is between this plug & the mower
You will most likely find an earth wire somewhere that is broken at the terminal.
