Honda Harmony HRB215SXA Owner's Manual page 51

MAINTENANCE
2. Remove the spark plug with a
21 mm ('3/ls in) spark plug
wrench.
3. Inspect the spark plug. Replace
it if the electrodes are worn, or
if the insulator is cracked or
chipped. Clean the spark plug
with a wire brush if you are
going to reuse it.
4. Measure the spark plug
electrode gap with a suitable
gauge. The gap should be
0.7 - 0.8 mm (0.028 - 0.031 in).
Correct the gap, if necessary,
by carefully bending the side
electrode.
5. Install the spark plug carefully, by
hand, to avoid cross-threading.
6. After the spark plug seats,
tighten with a 21 mm (13/ls in)
spark plug wrench to compress
the washer.
If reinstalling the old spark plug,
tighten l/s to l/d turn after the
spark plug seats.
If installing a new spark plug,
tighten l/2 turn after the spark
plug seats to compress the
washer.
SPARK PLUG WRENCH 1
0.7 - 0.8
mm
(0.028 - 0.031
in)
A loose spark plug can overheat and damage the engine.
Overtightening the spark plug can damage the threads in the
cylinder head.
7. Install the spark plug cap on the spark plug.