If it has battery ignition system (it should have battery ignition from your id tag 507X5A) you have to have 12VDC to the coils from the keyswitch (blue wire). The system use 12VDC from battery to supply the ignition system. If no 12VDC........ no spark.
The engine stops when you turn of the keyswitch (cut off the 12VDC to the coils).