Mooney M20M - Adjustment; Description; Operational Procedures; Reinstall

SERVICE AND
MAINTENANCE
MANUAL
M20M
MOOND/ AIRCRAFT
CORPORATION
37-21-01
DESCRIPTION
7. Remove
Calibrated
gauge
after
verification.
The switch is
a
low
and
high
vacuum
sensing
37-30-00
DRY
AIR
PUMP
REPAIR
adjustable
unit.
3730-01
COUPLING
INSPECTION
AND
37Q1-M
-MAINTENANCE
REPLACEMENT
Check
for
switch
security
in instrument
and
all
wires
i.
Remove
vacuum
pump
from
engine
in
secureatswitch.
accordance
with
maintenance
manual,
Chapter
3741-03
-REMOVAL
57-11-03.
Disconnect
wires
and
unscrew
from
aff instrument
2.
If
coupling (1)
has
sheared,
remove
engine
housing.
coupling
drive
gear
(2)
from
engine
gear
housing.
3.
Use
a
screwdriver
or
similar
tool,
remove
pump
drive
coupling
(1)
from
coupling
drive
gear
(2)
and
3781-04
-REINSTALL
coupling
drive
gear
(3) being
careful
not
to
damage
drive
pins.
Install switch in
housing
and
tighten.
Reconnect
wires.
4.
Push
new
drive
coupling (1)
into
place
on
CAUTION
coupling
drive
gear
(3).
Do
not
over
tighten.
Over
tightening
will
cause
cracking
of the
aft
instrument
housrng.
5.
Push
coupling
drive
gear
(2)
into
place
on
pump
drive
coupling (1).
6.
Tum
by
hand check
for
correct
rotation of
37121-05
-ADJUSTMENT
pump.
1.Remove
switch
from instrument.
Reinstall wires
if
7.
Reinstall
pump
on
engine
and
test
run
(refer
to
removed.
Attach
poly-vinyl
hose,
"T"
fitting
and
Chapter37-11-04)
calibrated
gauge
to
vacuum
switch.
Connect
other
end of hose
to
a vacuum source.
8.
Make
log
book
entry.
2.
Turn
aircraff
power
on.
The
"Hl/low
vac"
light
37-40-00
STAND-BY VACUUM SYSTEM
should
Rash.
3741-00 OPERATIONAL
PROCEDURES
3.
Apply
vacuum
and
adjust
source
to
4.25
(+/-0.2)
Adjust
Low
setting
screw
(connector
end
of
TheStand-by
Vacuum
Pumpassembly,
incorporated
to
illuminate the low
vacuum
circuit
on
the
on
the
M20hn,
is either
an
engine
mounted standard
annunciator
panel.
vacuum
pump
coupled
to
an
electric clutch
or
a
tailcone
mounted,
electrically
driven,
standard
4.
Increase
vacuum source
to
5.5
(+.2-.0)
In.
Hg.
pump
to
allow
operator
selected
ON/OFF
Punch
a
small
jewelers
screw
driver
through
the
operation
as
necessary.The
Stand-by
Vacuum
poly-vinyl
tube and into the
fitting
where
the
high
system
is
to
be
used,
only
as
needed,
when the
main
setting
screw
is
located and
adjust
until
the
"HI/LO
vacuum
pump
malfunctions. The
VAC
annunciator
VAC"‘light
on
annunciator
is illuminated,
light
will
iilumhate
(RED)
either
flashing (low
vacuum)
5.
After
you
have
completed
switch
adjustment
turn
or
steady thigh vacuum)
when
this
situation
occurs.
aircraft
power
off. If
annunciator
flashing
RED,
push
the
STBY VAC
6.
Remove
switch
from
hose and
gauge.
switch
ON
and
any
flashing
annunciator
light
should
extinguish
as
the
stand-by
vacuum
system
takes
over
7.
Reinstall switch in
Gym.
Reconnect
wires.
for all instrument
operations.
If
annunciator
light
is
CAUTION
steady
RED,
monitor
flight
instruments with
Crossing
the electrical
wires
on vacuum
switch
"O"-vacuum
gauges
and continue
Right
if
feasible,
or
land
and
have Vacuum
System
repaired.
Check
wIll
cause
the
annunciator
lights
to act
in
reverse.
vacuum
regulator
for
malfunction.
WARNING
31-22-00 GAUGE ADJUSTMENT
Malfunction
of
main
pump
could be
caused
by
DIGITAL
27-0258
thru 27-TEA
some
contamlnatron within
vacuum
system
and
1.
See
Figure
39-48
for
location
of
adjustment
stand-by
vacuum
pump/clutch
assembly
could
potentiometer.
be
affected
by
the
same cause.
2. Tee in
calibrated Vacuum
Gauge
down
stream
of
Operation
of
the
engine
driven,
clutch actuated
Vacuum
Regulator.
stand-by
vacuum
pump
can
be
checked when
engine
is
running
by
the
following
procedures:
3.
Apply
vacuum
to
aircraft
system.
Use
separate
vacuum
supply
or
stand-by
vacuum
pump.
1.
Verify
indicator
RED button
on
C/B
panel
is
visible.
4.
Adjust
vacuum
gauge
potentiometer
to
read
same as
calibrated
vacuum
gauge.
2.
Turn
Stand-by
Vacuum
Pump
Switch
-ON.
5.
Adjust
regulator
to
4.8
in.
Hg.
3.
RED
indicator
button will
not
be
visible
if
stand-by
6.
Verify
aircraft
instrument
reads
same
as
VaCUU"
pump
is
oeating properly.
calibrated
gauge.
4.
Turn
Stand-by
Vacuum
pumps
switch
OFF.
37-21-01
499
OLDWILLWAYNE