AIR FILTER MAINTENANCE
Cleaning the Air Filter
Clean and re-oil the air filter every 10 hours of operation. It is
an important item to maintain. Failure to maintain the air filter
properly can result in poor performance or can cause
permanent damage to the engine.
1. Open the air filter cover. Unscrew the knob on the left
side of the cover. Swing the cover out (Fig. 16).
2. Remove the air filter (Fig. 16).
3. Wash the filter in detergent and water (Fig. 17). Rinse
the filter thoroughly and allow it to dry.
4. Apply enough clean SAE 30 motor oil to lightly coat the
filter (Fig. 18).
5. Squeeze the filter to spread and remove excess oil (Fig. 19).
6. Replace the filter (Fig. 16).
NOTE:
Operating the unit without the air filter, will
VOID
the
warranty.
7. Make sure the back plate is correctly positioned (Fig. 16).
8. Swing the air filter cover closed and tighten the knob
(Fig. 16).
5
ROCKER ARM CLEARANCE
This requires disassembly of the engine. If unsure or unqualified to perform this task, take the unit to an
authorized service center.
NOTE:
Inspect the valve to rocker arm clearance with a feeler gauge
after the first 10 hours of operation and every 25 hours of
operation.
• The engine must be cold when checking or adjusting the valve
clearance.
• This task should be performed inside, in a clean, dust free area.
1. Remove the six (6) screws on the back of the engine cover with a
Flat-head or T-25 Torx screwdriver (Fig. 21).
2. Disconnect the spark plug wire.
3. Clean dirt from around the spark plug. Remove the spark plug
from the cylinder head by turning a 5/8 in. socket
counterclockwise.
4. Remove the engine cover (Fig. 22).
5. Clean dirt from around the rocker arm cover. Remove the screw
holding the rocker arm cover with a large flat blade screwdriver or
Torx T-25 bit (Fig. 23). Remove the rocker arm cover and gasket.
6. Pull the starter rope slowly to bring the piston to the top of its
travel, (known as top dead center). Check that:
• The piston is at the top of its travel while looking in the spark plug
hole (Fig. 23).
• Both rocker arms move freely, and both valves are closed.
If these statements are not true, repeat this step.
7. Slide the feeler gauge between the rocker arm and the valve
return spring. Measure the clearance between the valve stem and
rocker arm (Fig. 24). Measure both the intake and exhaust valves.
The recommended clearance for both intake and exhaust is
.003 –
.006 in. (.076 – 0.152 mm)
. Use a standard automotive .005 in.
(0.127 mm) feeler gauge. The feeler gauge should slide between the
rocker arm and valve stem with a slight amount of resistance,
without binding. See Figures 23 and 24.
8. If the clearance is not within specification:
a. Turn the adjusting nut using a 5/16 inch (8 mm) wrench or nut
driver (Fig. 24).
• To increase clearance, turn the adjusting nut counterclockwise.
• To decrease clearance, turn the adjusting nut clockwise.
b. Recheck both clearances, and adjust as necessary.
9. Reinstall the rocker arm cover using a new gasket. Torque the screw to
20–30 in•lb (2.2–3.4 N•m)
.
10.Check the spark plug and reinstall. See Replacing the Spark Plug.
11.Replace the spark plug wire.
12.Reinstall the engine cover. Check alignment of the cover before tightening the screws. Tighten
screws.
REPLACING THE SPARK PLUG
Use a replacement part
753-05784
or a Champion® ref. #
RDZ4H
spark plug. The correct air gap is
0.025 in. (0.635 mm.). Remove the plug after every 25 hours of operation and check its condition.
1. Stop the engine and allow it to cool. Remove the six (6) screws on the back of the engine cover with
a Flat-head or T-25 Torx screwdriver (Fig. 25).
2. Grasp the plug wire firmly and pull the cap from the spark plug.
3. Clean dirt from around the spark plug. Remove the spark plug from the
cylinder head by turning a 5/8 in. socket counterclockwise.
4. Replace cracked, fouled or dirty spark plug. Set the air gap at
0.025 in.
(0.635 mm)
using a feeler gauge (Fig. 25).
5. Install a correctly-gapped spark plug in the cylinder head. Turn the 5/8
in. socket clockwise until snug.
If using a torque wrench torque to:
110-120 in.•lb. (12.3-13.5 N•m) Do not over tighten.
WARNING:
Do not sand blast, scrape or clean electrodes. Grit in the
engine could damage the cylinder.
Fig. 25
0.025 in.
(0.635 mm.)
Fig. 21
WARNING:
To avoid serious personal injury, always turn the unit off and allow it to cool before
cleaning or servicing it.
Screws
Screws
Screws
WARNING:
To avoid serious personal injury,
always turn the unit off and allow it to cool
before cleaning or maintaining it.
IDLE SPEED ADJUSTMENT
The idle speed of the engine is adjustable. An idle adjustment screw is between the air filter cover and
the engine starter housing (Fig. 19).
NOTE:
Careless adjustments can seriously damage the unit. Aside from idle speed, only a qualified
service dealer should make carburetor adjustments.
First, Check Fuel
Old fuel is usually the reason for improper unit performance. Drain and refill the tank with fresh fuel
prior to making any adjustments. Refer to Oil and Fuel Information.
Second, Clean Air Filter
The condition of the air filter is important to the operation of the unit. A dirty air filter will restrict air
flow. This is often mistaken for an out of adjustment carburetor. Check the condition of the air filter
before adjusting the idle speed screw. Refer to Air Filter Maintenance.
Third, Adjust Idle Speed Screw
If, after checking the fuel and cleaning the air filter, the engine still will not idle, adjust the idle speed
screw as follows:
1. Start the engine and let it run at a high idle for a minute
to warm up. Refer to Starting/Stopping Instructions.
2. Release the throttle trigger and let the engine idle. If the
engine stops, insert a small phillips in between the Air
Filter Cover and the Engine Cover (Fig. 20). Turn the idle
speed screw in, clockwise, 1/8 of a turn at a time (as
needed) until the engine idles smoothly.
NOTE:
The cutting attachment should not rotate when the
engine idles.
3. If the cutting attachment rotates when the engine idles,
turn the idle speed screw counterclockwise 1/8 of a turn at a time (as needed), to reduce idle
speed.
Checking the fuel, cleaning the air filter, and adjusting the idle speed should solve most engine problems. If
not and any of the following are true have the unit serviced by a qualified service dealer:
• the engine will not idle
• the engine hesitates or stalls on acceleration
• there is a loss of engine power
Fig. 20
Idle Adjustment
Screw
MAINTENANCE AND REPAIR INSTRUCTIONS
MAINTENANCE AND REPAIR INSTRUCTIONS
Spark
Plug
Hole
Fig. 22
Rocker Arm
Cover
Feeler
Gauge
Fig. 23
Intake
Exhaust
Fig. 24
0.003 - 0.006 in.
(0.076 - 0.152mm)
Adjustment Nut
Valve
Rocker
Arm
WARNING:
The tines may spin during idle speed adjustments. Wear protective clothing and observe
all safety instructions to prevent serious personal injury.
Fig. 16
Air Filter Cover
Back Plate
Fig. 17
Air Filter
Hooks
Knob
Fig. 18
Fig. 19
