Servicing The Spark Plug; Cleaning The Blower Housing - Toro TimeCutter MX 3450 74750 Operator's Manual

Servicing the Spark Plug

Service Interval: Every 50 hours—Check the spark plug.
Every 100 hours—Replace the spark plug.
Ensure that the air gap between the center and side electrodes
is correct before installing the spark plug. Use a spark plug
wrench for removing and installing the spark plug and a
gapping tool or feeler gauge to check and adjust the air gap.
Install a new spark plug if necessary.
Type: Champion RC12YC, Autolite 3924, NGK BCPR6ES
or equivalent
Air Gap: 0.76 mm (0.03 inch)
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. Before removing the spark plug(s), clean the area
around the base of the plug to keep dirt and debris out
of the engine.
3. Remove the spark plug
A
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Figure 36
Checking the Spark Plug
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.
Note: 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).
A
Figure 37
(Figure 36).
B
B
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Installing the Spark Plug
Tighten the spark plug to 20 N-m (15 ft-lb).
A
C
15 ft-lb
20 N-m

Cleaning the Blower Housing

To ensure proper cooling, make sure the grass screen, cooling
fins, and other external surfaces of the engine are kept clean
at all times.
Annually or every 100 hours of operation (more often under
extremely dusty, dirty conditions), remove the blower housing
and any other cooling shrouds. Clean the cooling fins and
external surfaces as necessary. Make sure the cooling shrouds
are installed after finishing the maintenance. Torque the
blower-housing screws to 7.5 N-m (5.5 ft-lb).
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.
31
B
D
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Figure 38