Piper Navajo PA-31 Service Manual page 471

PIPER NAVAJO SERVICE MANUAL
a.
With the engine shut down and blades vertical, secure to the airplane a smooth board just under
the tip of the lower blade. Move the tip fore and aft through its full "blade-shake" travel, making small
marks with a pencil at each position. Then center the tip between these marks and scribe a line on the
board for the full width of the tip.
b. Carefully rotate propeller by hand to bring the opposite blade down. Center the tip and scribe a
pencil line as before and check that lines are not separated more than .062 inch.
c. Propellers have excess blade track should be removed and inspected for bent blades, or for parts
of sheared O-ring, or foreign particles, which have lodged between hub and crankshaft mounting faces. Bent
blades will require repair and overhaul of assembly. Other conditions will require installation in the
prescribed manner. (Refer to Paragraph 8-18.)
8-21. PROPELLER GOVERNOR.
8-22. REMOVAL OF PROPELLER GOVERNOR.
a.
Remove the upper engine cowl per Paragraph 8-4.
b. Disconnect the control cable end from the governor control arm.
c. Remove the governor mounting stud nuts. It will be necessary to raise the governor as the nuts
are being removed before the nuts can be completely removed.
d. Remove the mounting gasket. If the governor is to be removed for a considerable length of time
and another unit not substituted, it is advisable to cover the mounting pad to prevent damage caused by
foreign matter.
8-23. INSTALLATION OF PROPELLER GOVERNOR.
a. Clean the mounting pad thoroughly, making very certain that there are no foreign particles in the
recess around the drive shaft.
b. Place the governor mounting gasket in position with the raised portion of the screen facing away
from the engine.
c. Align the splines on the governor shaft with the engine drive and slide the governor into position.
d. With the governor in position, raise the governor enough to install washers and start mounting
nuts. Torque nuts even.
e.
Connect the control cable end to the governor control arm. The ball stud is installed in the outer
hole of the control arm.
f. Adjust governor control per Paragraph 8-24.
g. Install engine cowl per Paragraph 8-6.
8-24. RIGGING AND ADJUSTMENT OF PROPELLER GOVERNOR. (Refer to Figure 8-5.)
a. Start the engine and warm in the normal manner.
b. To check high RPM, low pitch setting, move the propeller control all the way forward to the
INCREASE PROPELLER position. At this position the governor speed control arm (1) should be against
the high RPM fine adjusting screw (2). With the throttle full forward, observe engine RPM, which should be
2575 RPM with high RPM properly adjusted.
c. Should engine RPM not be as required, the high RPM setting should be adjusted as follows:
1. Shut down the engine and remove the upper engine cowl.
2. Adjust the governor by means of the fine adjustment screw (2) for 2575 RPM. To do this,
loosen the high RPM fine adjustment screw lock nut and turn the screw in a clockwise direction to decrease
engine speed or in a counterclockwise direction to increase engine speed.
NOTE
One revolution of the fine adjustment screw will increase or
decrease the engine speed approximately 20 RPM.
Reissued: 10/12/79
POWER PLANT
2H21