Exmark Quest 4500-450 - Manual (Page 34)

Maintenance
As stated in the maintenance intervals, remove the
spark plug, check condition, and reset the gap or
replace with a new plug as necessary.
The spark plug is RFI compliant. Equivalent alternate
brand plugs can also be used.
Type: Champion XC92YC
Champion RC12YC or QC12C may be used if your
area does not require compliance with Canadian
ICES-002, ISO 14982, or EN 55012.
Air Gap: 0.030 inch (0.76 mm)
Removing the Spark Plug
1. Disengage the blade control switch, move the
motion controls outward to the park position,
stop the engine, and remove the key.
2. Pull the wire off of the spark plug (Figure 25).
Clean around the spark plug to prevent dirt from
falling into the engine and potentially causing
damage.
Note: Due to the deep recess around the spark
plug, blowing out the cavity with compressed air
is usually the most effective method for cleaning.
The spark plug is most accessible when the
blower housing is removed for cleaning.
3. Remove the spark plug and metal washer.
Figure 25
1. Spark plug and wire location
Checking the Spark Plug
1. Look at the center of the spark plug (Figure 26).
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.
Always replace the spark plug when it has a
black coating, worn electrodes, an oily film,
or cracks.
2. Check the gap between the center and side
electrodes (Figure 26). Bend the side electrode if
the gap is not correct.
Figure 26
1. Side electrode 3. Air gap (not to scale)
2. Center electrode
insulator
Installing the Spark Plug
1. Install the spark plug. Make sure that the air gap
is set correctly.
2. Tighten the spark plug to 15 ft-lb (20 N-m).
3. Push the wire onto the spark plug (Figure 25).
Cleaning the Blower Housing
Service Interval: Every 100 hours/Yearly
(whichever comes first)
More often under dirty
conditions.
To ensure proper cooling, make sure the grass screen,
cooling fins, and other external surfaces of the engine
are kept clean at all times.
1. Remove the blower housing and any other cooling
shrouds.
2. Clean the cooling fins and external surfaces as
necessary.
3. Make sure the cooling shrouds are reinstalled
Important: Operating the engine with a blocked
grass screen, dirty or plugged cooling fins,
and/or cooling shrouds removed, will cause
engine damage due to overheating.
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