Cleaning The Cooling System - Toro 74920 Operator's Manual

check and adjust the air gap. Install a new spark plug(s)
if necessary.
Type: NGK BPR4ES (or equivalent)
Air Gap: 0.030 inch (0.76 mm)
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.
Figure 48
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.
Checking the Spark Plug
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.
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 0.030 inches (0.76 mm).
1
Figure 49
2
G008794
Installing the Spark Plug
Tighten the spark plug(s) to 16 ft-lb (22 N-m).
16 ft-lb
22 N-m

Cleaning the Cooling System

Clean the air intake screen from grass and debris before
each use.
1. Disengage the blade control switch and move the
control levers to the neutral locked position and
apply the parking brake.
2. Stop the engine, remove the key, and wait for all
moving parts to stop before leaving the operating
position.
3. Remove the air intake screen, air cleaner cover, and
fan housing.
4. Clean debris and grass from the parts.
5. Install the air intake screen, air cleaner cover, and
fan housing.
40
G010687
Figure 50