Craftsman 25cc 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 Cleaning 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 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 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. Fig.22 WARNING: DO NOT SAND BLAST, SCRAPE, OR CLEAN SPARK PLUG ELECTRODES. GRIT IN THE ENGINE COULD DAMAGE THE CYLINDER. 0.02 in. (0.5 mm) Fig.23 14 LEHR | ALL RIGHTS RESERVED 2008-2009