We put two drops of smoke fluid in but it did not generate smoke or heat up.
Postwar Lionel smoke units are fairly durable.
The two most common problems with them are:
physical damage caused by someone sticking something into the stack
overfilling.
When pellets are used, the left over material remains in the smoke unit, even after years and years.
People would get out their trains and start playing with them..... what's the first thing they would do..... add a pellet.
And sometimes people would add more pellet(s) in an attempt to get more smoke.
The smoke unit would wind up so full, that the piston vent hole would clog, and eventually the heater wouldn't be able to generate enough heat to melt the entire mass.
If you want to determine whether the element is good, the best way is to remove the smoke unit from the loco, and use a vom to determine the resistance of the smoke unit. One probe on the metal case of the smoke unit. The other on terminal where the smoke unit power wire is attached. If the element is good, you should get a reading somewhere around 12 to 18 ohms. If it is bad, you should get infinity.
As far as a switch goes: Postwar smoke units don't need them. You can run them dry without damage.
