[FrankJ]

Lawn mower dead man switches typically ground the coil. Often, they are a piece of metal, not a switch in a conventional sense.

You can use the leaf limit switches that were on first choice this year. Or a spring return push button switch. You can also get them at Radio Shack. They will not carry motor current though. You can use them with a relay is rated for the current (Best) or drops the signal to the motor controllers.