Spark Plug Service - Honda HRM21PVA Owner's Manual

9. MAINTENANCE
SPARK PLUG SERVICE
RECOMMENDED SPARK PLUGS
REGULAR RESISTGR
NGK
B4H BR4HS
ND
W14F-U
W14FR-U
CHAMPION
L90
RL90
NOTE: Resistor spark plugs reduce interference with radio and TV
reception.
1 NOTICE 1
i I
Spark plugs of the wrong dimensions or heat range can cause
engine damage.
For good performance, the spark plug must be properly gapped and free of deposits.
1. Disconnect the spark plug cap, and remove any dirt from around the spark plug area.
(1
Touching the engine or exhaust system while hot can cause
bums. Let the engine cool before servicing.
2. Remove the spark plug with a 13/16 inch 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 feeler gauge. The gap should be
0.024-0.028 in (0.6-0.7 mm). Correct the gap as necessary by carefully bending
the side electrode.
5. Install the spark plug carefully, by hand, to avoid cross-threading.
6. After the spark plug is seated, tighten with a 13/16 inch spark plug wrench to
compress the washer.
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A loose spark plug can get hot enough to damage the engine.
Overtightening can damage the threads.
NOTE: If installing a new spark plug, tighten l/2 turn after the spark plug seats
to compress the washer. If reinstalling a used spark plug, tighten l/8-1 /4 turn after
the spark plug seats.
7. Install the spark plug cap on the spark plug.
13/16 INCH
,;
d
0.024-0.028 in
(0.6-0.7 mm)