MOONEY INTERNATIONAL CORPORATION
M20V SERVICE AND MAINTENANCE MANUAL
Date
MAR 2017
Rev Date
Page
10
A. Operate engine at 1500 to 1800 RPM until CHT
instrument indicator is GREEN BAND and oil tempera-
ture is 160 to 180 F.
B. Reduce engine speed and stabilize it at 650
RPM using cockpit throttle control.
C. Slowly, but positively, move mixture control from
full rich to idle cut off. Engine speed shall increase 50
+/- 25 RPM before beginning to drop toward zero.
D. If engine speed increase is less than 25 RPM,
adjust idle mixture to enrich. If engine speed increase is
more than 75 RPM, adjust idle mixture screw to leaner
mixture. Mixture adjustment screw (Fig. 71- 3), turn
clockwise to lean).
Recheck idle mixture to insure it is within specified lim-
its. Recheck idle pressure. Also refer to CMI Service In-
formation Directive SID97- 3(G) or latest FAA ap-
proved revision and M- O Standard practice
Maintenance Manual.
-NOTE-
Lightly tap fuel metering valve after each
adjustment.
-NOTE-
Any readjustment to idle pressure or mixture
may cause change to other readings. Recheck all
specified readings.
4. FULL POWER PERFORMANCE
Check and adjust full power performance as follows:
A. Adjust fuel flow to 177- 180 LBS/HR mixture
control in full rich position. (Fig. 71- 3). Unmetered
Pump to 20.5- 23.5 PSI, Metered Nozzle to 10.4- 11.6
PSI, Fuel to 30.0- 30.7 GAL/HR with throttle set at full
power (2500 rpm). Also refer to CMI Service Informa-
tion Directive SID97- 3(G) or latest revision, M- O Stan-
dard practice Maintenance Manual and the M- 18 Ser-
vice and Overhaul Manual for specific Engine
Operating Limits.
-NOTE-
Mixture and propeller controls must be full
forward.
-NOTE-
Lightly tap fuel pump after each adjustment.
-NOTE-
The Best Power setting will develop the
maximum horsepower and speed for a particular
manifold pressure and rpm setting. Best Power
mixture is desirable for minimizing flight time
when fuel burn rate or range i s not a primary
concern. When TIT limitations prevent attaining
peak TIT then best power is obtained at 1650F
TIT.
B. Recheck idle pressure setting as specified in 2
above and adjust as required.
C. Recheck 100 percent power fuel flow as speci-
fied in 5. A. and adjust as required.
-CAUTION-
Do not exceed 2500 RPM under any circum-
stances during the full power adjustment
process.
5. IDLE SPEED
Check and adjust idle speed as follows:
A. Operate engine at 1500 to 1800 RPM until CHT
(maintain CHT during adjustment) is in GREEN BAND
and oil temperature is 160 to 180F. Al so re fer t o C MI
Service Information Directive SID97- 3(G) or latest re-
vision.
B. Reduce engine speed and stabilize at 750 RPM.
C. Adjust idle speed adjusting screw (Fig. 73- 3)
until contact is made with throttle arm stop.
-NOTE-
Fuel flow will vary with temperature changes.
Temperature variations from NACA STANDARD
DAY temperature causes approximately .7 lbs/hr.
fuel flow change with each 1C. variation (minus
if hotter, plus if colder).
If RPM changes appreciably after making idle mixture
adjustment during the succeeding steps, readjust as
necessary.
71-00-51
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