I think schutzstaffel is right. To add to his advice I would tell you that the smoke unit is a great idea but poorly executed. The main problem is there's too much "batting" inserted into the unit. This is a fibrous cloth-like material meant to keep the oil from coming out of the reservoir and to keep the heating element supplied with smoke oil. Basically a sponge that feeds the mechanism.

Someone else had already discovered this excess of material in the smoker but it does seem to clog up the smoker to a noticeable degree. When I opened my smoker, there was batting everywhere and some stuffed right underneath the exit pipes (or where the smoke exits the pump and enters the vinyl tubing). Once I removed the excess, I ran the smoke unit and the output was increased. Will know more when I re-seal the reservoir and re-connect the tubes.

As for buying just any old oil from a hardware shop as a replacement--I would advise against that as it might be uncompatible with your smoker. I think the smoke oil used for model locomotives would be suitable. Hmm, some experimentation seems to be in order though............

-Harq