Piper COMANCHE PA-24-180 Service Manual page 463

PIPER COMANCHE SERVICE MANUAL
FIGURE 7C-7. FUEL INJECTOR
d
When the idling speed has been stabilized. move the cockpit mixture conrol with a smooth, steady
pull toward the "Idle Cut-Off" position and observe the tachometer for any change during the "leanmng'
process. Caution must be exercised to return the mixture control to the "Full Rich" position before the
RPM can drop to a point where the engine cuc our. An increase of more than 50 RPM while "leaning our"
indicates in excessively rich idle mixture. An immediate decrease in RPM (if not preceded by a momentary
increase) indicates the idle miture is too lean.
e.
If the above indicates that the idle adjustment is too rich or too lean, turn the idle mixture
adjustment in the direction required for correction. and check this new position by repeating the above
procedure. Make additional adjustments as necessary Each rime the adjustment is changed. the engine
should be run up to 2000 RPM to clear the engine before proceeding with the RPM check. Make final
adjustment of the idle speed adjustment to obtain the desired idling RPM with closed throttle. The above
method aims ar a setting that will obtain maximum RPM with minimum manifold pressure. In case the
setting does not remain stable, check the idle inkage, any looseness in this linkage would cause erratic
idling. In all cases, allowance should be made for the effect of weather conditions and field altitude upon
idling adjustment.
POWER PLANT
ISSUED: 8/18/72
2 H9