ENGlNE TO ADJUST CARBURETOR (See Fig. 18 ) TOP NO LOAD SCREW Minor carburetor adjustments may be required to com- pensate for differences in fuel, temperature, altitude or toa.d. The air cleaner and air cleaner cover must be assembled to carburetor when running. IDLE SPEED ADJUSTING SCREW INITIAL ADJUSTMENT- With the engine not running, gently turn idle mixture screw clockwise until it just closes. Screw may be damaged by turning it in too far. IDLE MIXTURE Next open the screw one turn counter-clockwise. This initial adjustment will permit the engine to be started and warmed up (approximately 5 minutes) prior to final ad- justment. NOTE: DO NOT adjust top no load adjusting screw.
It was pre-set at the factory, FIG. 18 FINAL ADJUSTMENT- Place engine speed control lever in "IDLE" or "SLOW" (,g_) position. Adjust idle RPM by turning idle speed adjusting screw to obtain 1400 RPM. Next, turn idle mixture screw in (clockwise- lean mixture) until engine just starts to slow. Then turn idle mixture screw out (counter-clockwise - rich mixture) until engine runs unevenly. Now turn idle mi_ure screw midway between rich and lean. Engine should accelerate smoothly. If engine does not accelerate properly, the carburetor should be readjusted, usually to a richer mixture, by turning the idle mixture screw counter- clockwise 1/8 turn more.
ENGINE SPEED Your engine speed has been factory set. Do not attempt to increase engine speed or it may result in personal injury. If you believe that the engine is running too fast or too slow, take your lawn mower to an authorized Sears Service Center for repair and adjustment. 16