the key has nothing to do with the foot start, it only makes/breaks the coil and accessory power, the starter is connected directly to the battery .... the only way you could be 'welding' the pedal arm [a good ground, being bolted to the bellhouse] to the starter button is if there is a direct short from the + in the starter to the button, which would be an un-insulated switch mechanism - have you taken it off and inspected it or are you depending on the shop?
Bill
