Boobie is correct, the motor only has one power pack.
Here is my understanding of how the kill circuit works: power is sent from the powerpack down the b/y wire to the ignition & kill switch. When the ignition is on and the killswitch lanyard attached this is a closed circuit that returns power back to the pack (presumably via the ignition wire that provided power to the pack in the first place). When the key is turned off or the killswitch lanyard pulled, it creates an open circuit that directs the power from the b/y wire to a ground, killing the motor. So if there is a bad connection somewhere along the b/y wire the motor is still able to run because it?s receiving power from the ignition/alternator (and nothing happens to that power when it reaches the b/y wire?s dead end) ? but it can?t be turned off because the b/y wire is no longer able transfer to a ground.
Is this correct?
Also assuming the motor isn?t dieseling, is there anything else that could cause this condition other than an issue somewhere along the circuit described above? I?ve seen alternator back feeding mentioned as a possible culprit in other threads, but don?t know anything about it.