:)Hi M C R
Both mark one and two old smokey use the same method to produce smoke. Mark one units came in two versions Steam or Diesel. You had to confirm when ordering which you required, operating voltage is the same for both units. The electronics for the mark two is different. You can now select diesel mode/steam mode/puffing steam engine mode and show mode.
Troubleshooting
Information taken from mark two hand book best operating voltage 12 volt lead acid battery not a ni cad battery. Overfilling will impair smoke generation. Water temp needs to be above 10 deg c and finally the fan speed is proportional to your speed controller/motor. If the fan is running very fast readjust the pot that controls the fan speed, the slower the fan the better the smoke output. I have 4 of these units and have tested 3 of them and found no problems during the operation on the test bench. Please be aware that the electronics package gets warm during operation so please allow some sort of air flow over the unit. Hope this has been of some help and I hope you manage to get the unit working. Mark two units come in a box marked mark 2 old smokey.