Spark Plug Service - Honda HP400 Owner's Manual

Spark plug service
Recommendedsparkplug: BPR4ES(NGK)W14EPMJ(NIPPONDENSO)
To ensure proper engine operation, the spark plug must be properly gapped
and free of deposits.
1. Remove the spark plug cap.
m The muffler becomes very hot during operation and re-
A l
.
mains hot for a while after stopping the engine. Be careful not to touch
the muffler while it is hot.
2. Clean any dirt from around the spark plug base.
3. Use a spark plug wrench to remove the spark plug.
PLUG WRENC
4. Visually inspect the spark plug. Discard it if there is apparent wear or it the
insulator is cracked or chipped. Clean the spark plug with a wire brush if it
is to be reused.
5. Measure the plug gap with a feeler gauge.
The gap should be 0.7-0.8 mm (0.028-0.031 in). Correct as necessary by
carefully bending the side electrode.
PLUG GAP:
0.7
-
0.8
mm
(0.028
-
0.031
in)
SIDE
ELEC-
TRODE
0
6. Make sure the spark plug washer is in good condition and thread the spark
plug by hand to prevent cross-threading.
7. After the spark plug is seated, tighten with the supplied spark plug wrench
to compress the washer.
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