Toro Z Master 4000 Series Operator's Manual page 49

Removing the Spark Plug
1. Park the machine on a level surface, disengage
the blade-control switch (PTO), and engage the
parking brake.
2. Shut off the engine, remove the key, and wait
for all moving parts to stop before leaving the
operating position.
3. Clean the area around the base of the plug(s) to
keep dirt and debris out of the engine.
4. Locate and remove the spark plug(s) as shown
in Figure 63.
Checking the Spark Plug(s)
Important:
Do not clean the spark plug(s).
Always replace the spark plug(s) when it has a
black coating, worn electrodes, an oily film, or
cracks.
If you see light brown or gray on the insulator, the
engine is operating properly. A black coating on the
insulator usually means the air cleaner is dirty.
Set the gap to 0.76 mm (0.030 inch).
Figure 63
Figure 64
Installing the Spark Plug
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Figure 65
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