Segway AT5 S Owner's Manual page 133

The spark plug is located under the seat. Please refer to page 53
for removing the seat.
1. Remove the ignition coil fixing bolts.
2. Take out the ignition coil.
3. The spark plug is located below the ignition coil. Use tool to
turn the spark plug cap 1/4 and remove it from the spark plug.
4. Rotate the spark plug counterclockwise and remove it.
5. Inspect the spark plug.
Spark plug normal status: The electrode part is grayish white,
grayish yellow or light brown, and the electrode gap is 0.6-
0.8mm.
Spark plug to be replaced: The spark plug appears electrode
ablation, carbon deposition, clearance is too large. At this time the
spark plug should be replaced.
MAINTENANCE, STORAGE AND TRANSPORTATION
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