Spark Plug; Cooling Fins - Honda GX25 Owner's Manual

Inspection (paper air filter element type)
See Figures 8, page A-3.
Loosen the screw [1] and remove the air cleaner cover [2].
Inspect the air filter element [3]. Clean or replace dirty air filter
element. Always replace damaged air filter element.
Reinstall the air filter element and air cleaner cover and tighten
the screw securely.
Refer to the cleaning instruction as following.
Cleaning (paper air filter element type)
See Figure 9, page A-3.
1. Loosen the screw [1] and remove the air cleaner cover [2].
2. Remove the paper air filter element [3] from the air cleaner
body.
3. Inspect the air filter element, and replace it if it is damaged.
Always replace the paper air filter element at the scheduled
interval (see page 4).
4. Clean the air filter element if it is to be reused.
Tap the paper air filter element several times on a hard
surface to remove dirt, or blow compressed air [not
exceeding 200 kPa (2.0 kgf/cm
element from the air cleaner body side. Never try to brush off
dirt; brushing will force dirt into the fibers. Replace the paper
air filter element if it is excessively dirty.
5. Wipe dirt from the inside of the air cleaner body and cover
using a moist rag. Be careful to prevent dirt from entering
the air duct that leads to the carburetor.
6. Reinstall the paper air filter element to the air cleaner body.
7. Install the air cleaner cover, and tighten the screw securely.

SPARK PLUG

See Figure 10, page A-3.
Recommended Spark Plug: CM5H (NGK), CMR5H (NGK)
The recommended spark plug has the correct heat range for
normal engine operating temperatures.
An incorrect spark plug can cause engine damage.
For good performance, the spark plug must be properly gapped
and free of deposits.
1. Loosen the hex bolt [1] with a hexagon wrench, then remove
the top cover [2].
Do not operate the engine when the top cover is
removed.
Do not pull the recoil starter handle when the top
cover is removed.
You may be injured from the rotating parts or burned
by the muffler.
6
2
, 29 psi)] through the filter
2. Disconnect the spark plug cap [3], and remove any dirt from
around the spark plug area.
3. Remove the spark plug [4] with a 5/8-inch spark plug wrench.
4. Inspect the spark plug. Replace it if damaged or badly fouled,
if the sealing washer [5] is in poor condition, or if the
electrode is worn.
5. Measure the spark plug electrode gap with a wire-type feeler
gauge. Correct the gap, if necessary, by carefully bending
the side electrode.
The gap should be: 0.6–0.7 mm (0.024–0.028 in)
6. Install the spark plug carefully, by hand, to avoid
cross-threading.
7. After the spark plug is seated, tighten with a 5/8-inch spark
plug wrench to compress the sealing washer.
When installing a new spark plug, tighten 1/2 turn after the
spark plug seats to compress the washer.
When reinstalling the original spark plug, tighten 1/8–1/4 turn
after the spark plug seats to compress the washer.
TORQUE: 11.8 N·m (9 lbf·ft, 1.2 kgf·m)
A loose spark plug can overheat and damage the engine.
Overtightening the spark plug can damage the threads in the
cylinder head.
8. Attach the spark plug cap to the spark plug.
9. Install the top cover, and tighten the hex bolt securely with a
hexagon wrench.

COOLING FINS

See Figure 11, page A-3.
Inspection and clean
1. Loosen the hex bolt, then remove the top cover.
2. Disconnect the spark plug cap (see page 6).
3. Inspect the engine cooling fins [1], and clean out debris if
necessary.
4. Reconnect the spark plug cap.
5. Install the top cover, and tighten the hex bolt securely.
ENGLISH