As an aside, I was demonstrating the use of the kill cord to a new passenger a couple of months ago. Imagine my suprise when it didn't kill the engine! I hadn't tested it for a couple of months, I don't care to think how long it hadn't been working for. Turns out that most kill cords kill the engine by completing an electrical circuit, not breaking it. So if you've got some corrosion, leading to poor contacts, the kill cord won't work.
The moral of this story? I check the kill cord at the start of every days ribbing now.