Engine Speed - Craftsman 917.373231 Owner's Manual

ENGINE
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 service
center for repair and adjustment°
TO ADJUST CARBURETOR (See Fig. 19)
Minor carburetor adjustments may be required to com-
pensate for differences in fuel, temperature, altitude or
load,. The air cleaner and air cleaner cover must be
assembled to carburetor when running.
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..
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 adjust-
menL
NOTE: Do not adjust top no load adjusting screw_ It was
pre-set at the factory..
FINAL ADJUSTMENT-
Place engine speed control lever in idle or slow (,_.)
position° Adjust idle RPM by turning idle speed adjusting
screw to obtain 1700 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 mixture
screw midway between rich and leano Engine should
accelerate smoothly, If engine does not accelerate prop-
erly, the carburetor should be readjusted, usually to a
richer mixture, by turning the idle mixture screw counter-
clockwise 1/8 turn more.
TOP NO
LOAD
SCF
IDLE SPEED
ADJUSTING
SCREW
IDLE
MIXTURE
SCREW
FIG. 19
IMPORTANT: NEVER TAMPER WITH THE ENGINE
GOVERNOR, WHICH IS FACTORY SET FOR PROPER
ENGINE SPEED OVERSPEEDING THE ENGINE ABOVE
THE FACTORY HIGH SPEED SETTING CAN BE
DANGEROUS, IF YOU THINKTHE ENGINE-GOVERNED
HfGH SPEED NEEDS ADJUSTING, CONTACT YOUR
NEAREST AUTHORIZED SERVICE CENTER, WHICH
HAS PROPER EQUIPMENT AND EXPERIENCE TO
MAKE ANY NECESSARY ADJUSTMENTS,,
17