Craftsman 25cc - Propane Curved Shaft Trimmer Powered by Lehr Operation Manual page 14

MAINTENANCE
CARURETOR ADJUSTMENT
The idle speed of the engine is adjustable. An idle adjust -
ment screw is on the rear side of the carburetor (Fig. 22).
NOTE: Careless adjustments can seriously damage
your unit. An authorized service dealer should make
carburetor adjustments.
CLEAN AIR FILTER
The condition of the air lter is important to the op -
eration of the unit. A dirty or oil saturated air lter will
restrict air ow. This is often mistaken for an out of ad -
justment carburetor. Check the condition of the air lter
before adjusting the idle speed screw. Refer to
Air Filter (p. 13).
ADJUST IDLE SPEED SCREW
If, after checking the fuel and cleaning the air lter, 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 min -
ute to warm up. Refer to Starting/Stopping (p. 10)
instructions.
2. Release the throttle trigger and let the engine idle. If
the engine stops, use a small phillips or at blade to
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.
Idle Adjustment
Screw
Fig.22
WARNING:
DO NOT SAND BLAST, SCRAPE, OR
CLEAN SPARK PLUG ELECTRODES.
GRIT IN THE ENGINE COULD DAMAGE
THE CYLINDER.
14
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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 lter, and
adjusting the idle speed should solve most engine
problems. If not and all of the following are true:
• the engine will not idle
• the engine hesitates or stalls on acceleration
•there is a loss of engine power
Check the spark plug for proper gap and condition. If
problem still occurs, have the carburetor adjusted by an
Cleaning
authorized service dealer.
REPLACING THE SPARK PLUGS
Use a replacement part number NGK CMR6A. The cor
rect air gap is 0.02 in. (0.5 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
spark plug cover. Grasp the plug wire rmly and pull
the cap from the spark plug.
2.Clean dirt from around the spark plug. Remove the
spark plug from the cylinder head by turning a 5/8 in.
socket counterclockwise.
3.Replace cracked, fouled or dirty spark plug. Set the air
gap at 0.02 in. (0.5 mm.) using a feeler gauge (Fig 23).
4.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)
NOTE: Do not over tighten.
0.02 in.
(0.5 mm)
Fig.23
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