Hyundai HY4BC31 User Manual page 29

SPARK PLUG
7.4 Carefully remove the spark plug HT lead cap.
7.5 Remove the spark plug using the box spanner provided in an anti-clockwise
direction.
7.6 Check the spark plug for visible damage and electrode erosion. If damaged you
MUST replace the spark plug.
7.7 Remove carbon deposits from the spark plug using a soft wire brush.
The spark plug gap should be 0.6 – 0.8mm.
7.8
Check the gap using a feeler gauge and adjust as necessary by carefully bending
the side electrode to achieve the correct gap.
7.9 Refit the cleaned and adjusted spark plug by hand to avoid cross-threading.
7.10 After spark plug seats then tighten as necessary but avoid over-tightening.
7.11 Re-attach the spark plug HT lead cap.
0.6 – 0.8mm
29