Servicing The Spark Plug - Toro 74593 Operator's Manual

Servicing the Spark Plug

Service Interval: Every 25 hours—Check the spark
plug.
Every 100 hours—Replace the spark
plug.
Use a Champion RC12YC or equivalent spark plug.
Ensure that the air gap between the center and side
electrodes is 0.030 inch (0.76 mm) 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.
Removing the Spark Plug
1. Disengage the blades (PTO).
2. Set the parking brake.
3. Stop the engine and wait for all moving parts to stop.
4. Remove the ignition key.
5. Open the hood.
6. Disconnect the wire from the spark plug (Figure 26).
Figure 26
1. Spark plug wire
7. Clean around the spark plug to prevent dirt from
falling into the engine and potentially causing
damage.
8. Remove the spark plug and the metal washer
(Figure 26).
Checking the Spark Plug
1. Look at the center of the spark plug (Figure 27).
If you see light brown or gray on the insulator, the
engine is operating properly. A black coating on the
insulator usually means that the air cleaner is dirty.
1. Center electrode insulator
2. Side electrode
Important: Do not 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 27) and bend the side electrode if the gap
is not correct.
Installing the Spark Plug
1. Install the spark plug and metal washer. Ensure that
the air gap is set correctly.
2. Tighten the spark plug to 15 ft-lb (20.4 N-m).
3. Connect the wire to the spark plug (Figure 26).
4. Close the hood.
25
Figure 27
3. Air gap (not to scale)