Piper Aircraft Corporation Malibu Mirage PA-46-350P, Airplane Maintenance Manual

Page: 1445 / 1956

PAGE 1
Feb 28/07 7G23
76-10-00
PIPER AIRCRAFT, INC.
PA-46-350P, MALIBU MIRAGE
MAINTENANCE MANUAL
POWER CONTROL
1. Engine Setup Procedures
WARNING: BEWARE PROPELLER BLAST AND ROTATING PROPELLER BLADES DURING ENGINE
OPERATION. EXERCISE CAUTION TO AVOID DAMAGE TO PERSONNEL AND
EQUIPMENT.
CAUTION: BEFORE ATTEMPTING FULL POWER CHECKS, BE SURE THAT THE BRAKES ARE
PROPERLY MAINTAINED AND SET, AND THAT THE GROUND CONDITIONS WILL NOT
PERMIT THE WHEELS TO SLIP DURING FULL POWER CHECK.
2. Idle Speed and Mixture Adjustment
CAUTION: IT IS EXTREMELY IMPORTANT THAT THE ENGINE BE THOROUGHLY WARMED UP.
HOWEVER, EXCESSIVE ENGINE TEMPERATURES MUST BE AVOIDED.
NOTE: Allow for the effect of weather conditions and field altitude when making idling adjustment.
A. Start and warm up the engine until the oil temperature reaches 170°F to 190°F.
B. Check magnetos. If the magneto drop is normal, proceed with idle adjustment.
C. Set throttle stop screw so that the engine idles at 700 rpm. If the rpm changes appreciably after
making idle mixture adjustment during the following steps, readjust the idle speed to the desired
rpm.
D. When the idling speed has stabilized, move the cockpit mixture control, with a smooth steady pull,
toward the Idle Cut-Off position and observe the tachometer for any change during the leaning
process. Caution must be exercised to return the mixture control to the Full Rich position before the
rpm drops to a point of engine cut out. An increase of more than 50 rpm while leaning out indicates
an excessively rich idle mixture. An immediate decrease in rpm (if not preceded by a momentary
increase) indicates the idle mixture is too lean.
E. If step (D) indicates that the idle mixture is too rich or too lean, turn the idle mixture adjustment in
the direction required for correction and check this new position by repeating step (D).
F. Make additional adjustments as necessary until a mixture check step (D) results in a momentary
pick up of approximately 50 rpm. Each time the adjustment is changed the engine should be run up
to 2,000 rpm to clear the engine before proceeding with the rpm check.
G. Make final adjustment of the idle speed adjustment to obtain an idle speed of 700 ± 25 rpm with
closed throttle and air conditioner off.
H. The above method aims at a setting that will obtain maximum rpm with minimum manifold pressure.
In case the setting does not remain stable, check the idle linkage; any looseness in this linkage
would cause erratic idling.