Mooney M20V - Page 489

MOONEY INTERNATIONAL CORPORATION
M20V SERVICE AND MAINTENANCE MANUAL
Date
MAR 2017
Rev Date
Page
11
TROUBLE SYMPTOM POSSIBLE CAUSE/REMEDY
Loss of Propeller Control:
Propeller goes to Uncommanded
Low Pitch (High RPM).
1 - Governor pressure relief valve
for proper operation.
2 - Governor drive for damage.
3 - Adequate engine oil supply.
4 - Engine transfer bearing leaking
excessively.
Propeller goes to Uncommanded
High Pitch (Low RPM).
Governor pilot valve sticking.
RPM Increases with Power and Air-
speed, Propeller RPM Control has
Little or No Effect.
1 - Excessive friction in blade bear-
ings or pitch changing mechanism.
2 - Internal oil leakage to opposite
side of piston and into hub.
Vibration: - CAUTION -
Any vibration that can be de-
scribed as appearing suddenly, or
is accompanied by unexplained
grease leakage, should be investi-
gated immediately before further
flight.
NOTE:
Vibration problems due to propel-
ler system imbalance are normally
felt throughout the RPM range,
with the intensity of vibration in-
creasing with RPM. Vibration
problems that occur in a narrow
RPM range are a symptom of res-
onance, which is potentially
harmful to the propeller. Avoid op-
eration until the propeller can be
checked by an appropriately li-
censed repair facility
Check:
1 - Control surfaces, cowl flaps, ex-
haust system, landing gear doors,
etc. for excessive play, which may
be causing vibration unrelated to the
propeller.
2 - Secure attachment of engine
mounted hardware.
3 - Engine mount wear.
4 - Uneven or over lubrication of
propeller.
5 - Proper engine/propeller flange
mating.
6 - Blade track (For procedure, see
Hartzell Owner’s Manual).
7 - Blade angles: Blade angle must
be within 0.2 degree from blade to
blade.
8 - Spinner for cracks, improper
installation, or ”wobble” during op-
eration.
9 - Static balance.
10 - Airfoil profile identical between
blades (after overhaul or rework for
nicks - verify at appropriately li-
censed propeller repair facility).
11 - Propeller installation - remove
and reinstall propeller 180 degrees
from original installation position.
12 - Hub or blade damage or crack-
ing.
13 - Grease or oil leakage from a
seemingly solid surface of the hub or
blade.
14 - Bends or blade deformation.
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