Re: Stuck on the lake now! SOS!!
Good to hear that you made it off the water OK... Yes, the key switch is the one that you use to start the motor and shut it off (with the key). It's good news that disconnecting the wire from the powerpack brought spark back. That means it's either a bad key switch, or more likely, cracked/broken/uninsulated wiring somewhere between it and the powerpack (like I said before)... that's cheaper than a new powerpack.
If yours doesn't have that, then the next thing I'd look for is for cracked/broken wires either on the engine, or between the engine and the control box. The wires can get brittle where they flex from when the motor is tilted up and down. If the insulation is cracked, the ignition could get shorted out (basically doing the same thing as when you normally turn the key off).
good luck.. and if you find a spot where the insulation or wiring broke, I'd recommend replacing that section of wiring. If you just splice it together, it will work for a while, but probably break again if the wire/insulation is brittle.