Honda Engine GX120 GX160 GX200 Owners Manual

							ª«
21
Air cleaner service
Never use gasoline or low flash point solvents for cleaning the air
cleaner element. A fire or explosion could result.
Never run the engine wit hout the air cleaner. Rapid engine wear
will result.
Dual element type
2.
WING NUT
(GX120/160/200)
(GX120/160) PAPER
ELEMENT
FORM
ELEMENT
A dirty air cleaner will restrict air flow to the carburetor. To prevent
carburetor malfunction, service the air cleaner regularly. Service
more frequently when operating the engine in extremely dusty
areas.
Remove the wing nut and the air
cleaner cover. Remove the elements
and separate them. Carefully check
both elements for holes or tears and
replace if damaged.
Foam element: Wash the element in
a solution of household detergent
and warm water, then rinse thor-
oughly, or wash in nonflammable or
high flash point solvent. Allow the el-
ement to dry thoroughly.
Soak the element in clean engine oil
and squeeze out the excess oil. The
engine will smoke during initial
start-up if too much oil is left in the
foam.
Paper element: Tap the element
lightly several times on a hard sur-
face to remove excess dirt, or blow
compressed air through the filter
from the inside out. Never try to
brush the dirt off; brushing will force
dirt into the fibers. Replace the pa-
per element if it is excessively dirty.
1.
2.
3. 
						

							ª«
22
When reinstalling the cyclone, ensure that the tab on the air
intake fits properly into the groove in the pre-cleaner cap.
Be careful to install the air guide in the proper direction. Cyclone type
WING NUT
GROOVE PAPER
ELEMENT
FOAM
ELEMENT
AIR INTAKE TAB
CYCLONE
AIR GUIDE
Paper element: Tap the element lightly several times on a hard
surface to remove excess dirt, or blow compressed air through
the filter from the inside out. Never try to brush the dirt off;
brushing will force dirt into the fibers. Replace the paper ele-
ment if it is excessively dirty. Remove the wing nut and the air
cleaner cover. Remove the
elements and separate them.
Carefully check both elements for
holes or tears and replace if
damaged.
Foam element: Clean in warm
soapy water, rince and allow to
dry thoroughly. Or clean in high
flash-point solvent and allow to
dry. Dip the element in clean
engine oil and squeeze out all the
excess. The engine will smoke
during initial start-up if too much
oil is felt in the foam.
(Cleaning the cyclone housing) When the cyclone housing becomes dirty, unscrew the three
special pan screws and wipe or wash the components with
water. Next, thoroughly dry the components and carefully
reassemble them.
3. 1.
2.
1. 
						

							ª«
ª«
23
Semi-dry type
Oil bath typeWING NUT
WING NUT
AIR CLEANER
COVER
AIR CLEANER
COVER
ELEMENT
ELEMENTUnscrew the wing nut, remove the air
cleaner cover and remove the element.
Wash the element in a nonflammable
or high flash point solvent and dry it
thoroughly.
Soak the element in clean engine oil
and squeeze out the excess oil.
Unscrew the wing nut, remove the air
cleaner cover and remove the element.
Empty the oil from the air cleaner case
and wash out any accumulated dirt
with nonflammable or high flash point
solvent. Dry the case.
Fill the air cleaner case to the level
mark with the same oil that is recom-
mended for the engine (see engine oil
recommendations on page ). Wash the element in a solution of
household detergent and warm water,
then rinse thoroughly, or wash in non-
flammable or high flash point solvent.
Allow the element to dry thoroughly.
Soak the element in clean engine oil
and squeeze out the excess oil. The
engine will smoke during intial start-
up if too much oil is left in the element.
Reinstall the element and the cover. Reinstall the air cleaner element and
the cover.
1.
2.
3.
4.
1.
2.
3.
4.
5.
6.
6 
						

							24
Sediment cup cleaning
Gasoline is extremely flammable and is explosive under certain
conditions. Do not smoke or allow flames or sparks in the area.
After installing the sediment cup, check for leaks, and make
sure the area is dry before starting the engine.
Spark plug service
Recommended spark plug:
Never use a spark plug of incorrect heat range.
If the engine has been running, the muffler will be very hot. Be
careful not to touch the muffler. 3.
4.
O-RING
SEDIMENT CUP
Turn the fuel valve to OFF. Remove the sediment cup and O-ring,
and wash them in nonflammable or high flash point solvent. Dry
them thoroughly and reinstall securely. Turn the fuel valve ON and
check for leaks.
To ensure proper engine operation, the spark plug must be
properly gapped and free of deposits. Remove the spark plug cap and use the proper size spark plug
wrench to remove the spark plug.
1.
BPR6ES (NGK)
W20EPR-U (DENSO) 
						

							µµµ
µ
µ
25
The spark plug must be securely tightened. An improperly
tightened spark plug can become very hot and may damage the
engine.
0.70 0.80 mm
(0.028 0.031 in)
0.70 0.80 mm (0.028 0.031 in)
Visually inspect the spark plug. Discard the spark plug if there is
apparent wear, or if the insulator is cracked or chipped. Clean
the spark plug with a wire brush if it is to be reused.
Measure the plug gap with a feeler gauge. Correct as necessary
by bending the side electrode.
The gap should be:
Check that each spark plug washer is in good condition, and
thread the spark plug in by hand to prevent cross-threading.
After the spark plug is seated, tighten with a spark plug wrench
to compress the washer.
When installing a new spark plug, tighten 1/2 turn after the spark
plug seats to compress the washer. When reinstalling a used spark
plug, tighten 1/8 1/4 turn after the spark plug seats to compress
the washer. 4.
5. 2.
3. 
						

							26
Spark arrester maintenance (optional part)
If the engine has been running, the muffler will be very hot. Allow
it to cool before proceeding.
The spark arrester must be serviced every 100 hours to maintain
its efficiency.
Be careful not to damage the spark arrester screen. 5.
MUFFLER PROTECTOR MUFFLER 4 mm SCREW
SCREEN EXHAUST DEFLECTOR
SPARK ARRESTER 4 mm SCREWS
5 mm SCREWS
Remove the two 4 mm screws from the exhaust deflector, and
remove the deflector.
Remove the four 5 mm screws from the muffler protector, and
remove the muffler protector.
Remove the two 4 mm screw from the spark arrester, and
remove the spark arrester from the muffler.
Use a brush to remove carbon deposits from the spark arrester
screen.
Install the spark arrester and the muffler in the reverse order of
disassembly.
The spark arrester must be free of breaks and holes. Replace, if
necessary. 4.
5. 1.
2.
3. 
						

							¶
27
Carburetor idle speed adjustment
6.
THROTTLE STOP SCREW
Standard idle speed:
Start the engine and allow it to warm up to normal operating
temperature.
With the engine idling, turn the throttle stop screw to obtain the
standard idle speed.
1.
2.
1,400 rpm.200
150 
						

							28
THROTTLE AND CHOKE CONTROL CABLE
(optional part)
THROTTLE LEVER
FRICTION NUT
FLEXIBLE WIRE
CORE MOUNTING
SOLID WIRE
CORE MOUNTING RETURN SPRING
THROTTLE LEVER
WIRE HOLDER
5 mm CIRCLIP
5 mm CIRCLIP
WIRE
4 mm SCREW
WIRE HOLDER
The throttle and choke control levers are provided with holes for
optional cable attachment. The following illustrations show
installation examples for a solid wire cable and for a braided wire
cable. If using a braided wire cable, add a return spring as shown.
It is necessary to loosen the throttle lever friction nut when
operating the throttle with a remote cable. 
						

							29
TRANSPORTING/STORAGE
When transporting the engine, turn the fuel valve OFF and keep
the engine level to prevent fuel spillage. Fuel vapor or spilled fuel
may ignite.
Gasoline is extremely flammable and is explosive under certain
conditions. Do not smoke or allow flames or sparks in the area.
DRAIN
SCREW
Align the mark on the starter
pulley with the hole at the top
of recoil starter. SEDIMENT CUP
Befor storing the unit for an extended period;
Be sure the storage area is free of excessive humidity and dust.
Drain the fule…
Change the engine oil (page 20).
Remove the spark plug and pour about a tablespoon of clean
engine oil into the cylinder.
Crank the engine several revolutions to distribute the oil, then
reinstall the spark plug.
Pull the starter rope slowly until resistance is felt.Continue
polling until the notch on the starter pulley aligns with the hole
on the recoil starter (see illustration below). At this point, the
intake and exhaust valves are closed, and this will help to
protect the engine from internal corrosion. With the fuel valve in the OFF position,
remove and empty the sediment cup.
Turn the fuel valve to the ON position
and drain the gasoline from the fuel
tank into a suitable container.
Replace the sediment cup and tighten
securely.
Drain the carbretor by loosening the
drain screw. Drain the gasoline into a
suitable container.
Electric starter type: Remove the battery and store it in a cool;,
dry place. Recharge it once a month.
Cover the engine to keep out dust.
1.
2.
a.
b.
c.
d.
3.
4.
5.
6.
7. 
						

							30
TROUBLESHOOTING
If any fuel is spilled, make sure the area is dry before testing the
spark plug or starting the engine. Fuel vapor or spilled fuel may
ignite.
DRAIN SCREW
Engine will not start using recoil starter:
Is the engine switch in the ON position?
Is there enough oil in the engine?
Is the fuel valve ON?
Is there fuel in the fuel tank?
Is gasoline reaching the carburetor?
To check,loosen the drain screw with the fuel valve ON?
Is there a spark at the spark plug?
If the engine still dose not start, take the engine to an authorized
Honda dealer.
Engine will not start, using electric starter: Are the battery cables securely connected and free of corrosion?
Is the battery fully charged?Remove the spark plug cap. Clean any dirt from around the
spark plug base, then remove the spark plug.
Install the spark plug in the plug cap.
Turn the engine switch ON.
Grounding the side electrode to any engine ground, pull the
recoil starter to see if sparks jump across the gap.
If there is no spark, replace the plug.
If OK, reinstall the spark plug and try to start the engine again
according to the instructions.
If the engine does not charge the battery, check the circuit breaker. If the starter motor operates, but the engine wil not start, follow
the troubleshooting procedure described under recoil starter
operation.
1.
2.
3.
4.
5.
6.
a.
b.
c.
d.
e.
7.
1.
2.
3.