Toro Z550 Z Master, Operator'S Manual

Page: 33 / 60

Removing the Spark Plug
1. Disengage the PTO, move the motion control levers
to the neutral locked position and set the parking
brake.
2. Stop the engine, remove the key, and wait for all
moving parts to stop before leaving the operating
position.
3. Pull the wire(s) off the spark plug(s) (Figure 37).
Now clean around the spark plug(s) to prevent dirt
from falling into the engine and potentially causing
damage.
4. Remove the spark plug(s) and metal washer.
Figure 37
1. Spark plug wire 2. Spark plug
Checking the Spark Plug
Service Interval: Every 100 hours
1. Look at the center of the spark plug(s) (Figure 38).
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.
Important:
Never clean the spark plug(s).
Always replace the spark plug(s) when it has: a
black coating, worn electrodes, an oily film, or
cracks.
Figure 38
1. Canter electrode insulator 3. Air gap (not to scale)
2. Side electrode
2. Check the gap between the center and side electrodes
(Figure 38). Bend the side electrode (Figure 38) if
the gap is not correct.
Installing the Spark Plug
1. Install the spark plug(s). Make sure the air gap is set
correctly.
2. Tighten the spark plug(s) to 16 ft.-lb (22 N
⋅
m).
3. Push the wire(s) onto the spark plug(s) (Figure 37).
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