Servicing The Spark Plug - Toro 74590 Operator's Manual

Servicing the Spark Plug

Check the spark plug after every 25 operating hours. Install
a new Champion RC12YC or equivalent spark plug after
every 100 operating hours. Ensure that the air gap between
the center and side electrodes is 0.030 in. (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 (Fig. 29).
1
Figure 29
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 metal washer.
Checking the Spark Plug
1. Look at the center of the spark plug (Fig. 30). 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.
2
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
(Fig. 30) 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 (Fig. 29).
4. Close the hood.
30
3
1
0.030 in.
(0.76 mm)
m-1870
Figure 30
3. Air gap (not to scale)