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MTH SD70MAC Operating Instructions
PROTOSMOKE™ UNIT OPERATION
The SD70MAC contains a self-powered smoke unit that outputs a steady stream of smoke
through the smoke stack on the roof of the engine. The ON/OFF switch located next to the
power truck must be in the ON position in order for the smoke unit to function. See Fig. 1 on
page 3.
The smoke unit is essentially a small heating element and wick which soaks up and then
“cooks" a mineral oil-based fluid that omits a harmless smoke. The smoke is then forced out
of the stack via a small electric fan which runs at a constant speed. However, the smoke
intensity can be varied by increasing the transformer voltage setting. The higher the setting,
the more intense the smoke output.
For best results, we recommend that you add 20 - 25 drops of ProtoSmoke™, Seuthe, LGB or
LVTS fluid before you run the engine. If you don’t choose to add the fluid, then the smoke
unit switch should be turned off. Failure to either add the fluid or turn the switch off could
lead to damage to the smoke unit heating element and or wicking. Add the fluid through the
smoke stack hole. After adding the fluid, gently blow into the stack to eliminate any air
bubbles. Do not overfill the unit as overfilling can cause the fluid to leak out and coat the
interior engine components. When the smoke output begins to diminish while running the
engine, an additional 20-25 drops of smoke fluid should be added or the smoke unit switch
should be turned off. When storing the engine for long periods of time, you may want to add at
least 20 drops of fluid to keep the wick soaked with fluid and prevent it from drying out. After
removing the engine from storage, it is advisable to add another 25 drops of fluid, letting the
wick soak up the fluid for 15 minutes prior to operation.
SMOKE UNIT MAINTENANCE
CAUTION:
Operating the engine without smoke fluid and with the smoke unit switch in the
ON position can damage your smoke unit wick, causing the wick to become hard, blackened
and unabsorbant around the heating element. When this occurs, it may be difficult for the wick
to soak up the smoke fluid resulting in poor or
no smoke output. If that occurs, we
recommend that you inspect and/or replace the
wick taking care to not run the engine without
fluid in the future. You can inspect the wick to
see if it needs replacement by removing the
smoke unit circuit board from the smoke unit
body as seen in Fig.2. After removing the
circuit board screws lift the circuit board away
and inspect the wick. If the wick is darkly
discolored and hard, it should be replaced.
Remove Circuit
Board Screws
Lift Circuit
Board Away To
Reveal Smoke Wick
Figure 2: Inspecting The Smoke Unit
