Cessna 177 SERIES Service Manual

15-26.
TROUBLE
SHOOTING--VACUUM
SYSTEM
TROUBLE
PROBABLE
CAUSE
REMEDY
HIGH
SUCTION
GAGE
READINGS.
Gyros
function
normally-relief
Check screen,
then
valve.
Com-
valve
screen
clogged,
relief
pare
gage
readings
with new
gage.
valve malfunction.
Clean screen,
reset
valve. Re-
place gage.
NORMAL
SUCTION
GAGE
Instrument
air filters
clogged.
Check
filter.
Clean
or
replace
READING,
SLUGGISH
OR
filter.
ERRATIC
GYRO
RESPONSE.
Leaks
or restriction
between
Check
lines for
leaks,
disconnect
LOW
SUCTION
GAGE
instruments
and
relief valve,
and
test pump.
Repair
or replace
READINGS.
relief
valve out
of adjustment,
lines,
adjust
or replace
relief
defective
pump or restriction
valve, repair
or replace
pump.
on pump
discharge
line.
Clean
discharge lines.
Central
air
filter
dirty.
Check
filter.
Clean
or
replace
filter.
SUCTION
GAGE
FLUCTUATES.
Defective
gage
or sticking
relief
Check suction
with
test gage.
valve.
Replace
gage.
Clean
sticking
valve
with
Stoddard
solvent.
Blow
dry and test.
If valve
sticks
after cleaning,
replace
valve.
15-27.
TROUBLE
SHOOTING--GYROS.
TROUBLE
PROBABLE
CAUSE
REMEDY
HORIZON
BAR FAILS
TO
Central
filter dirty.
Check
filter.
Clean or
replace
RESPOND.
filter.
Suction
relief valve
improperly
Adjust
or replace
relief valve.
adjusted.
Faulty
suction
gage.
Substitute
known-good
suction
gage
and check gyro
response.
Replace
suction
gage.
Vacuum
pump
failure.
Check pump.
Replace
pump.
Vacuum
line kinked
or leaking.
Check lines
for damage
and
leaks.
Repair
or replace damaged
lines,
tighten
connections.
HORIZON
BAR DOES
NOT
Defective
mechanism.
Substitute
known-good
gyro
and
SETTLE.
check indication.
Replace
in-
strument.
Insufficient
vacuum.
Adjust
or replace
relief
valve.
Excessive
vibration.
Check panel
shock-mounts.
Replace
defective
shock-mounts.
15-12 Change 6

Cessna 177 SERIES Specifications

General

Manufacturer	Cessna
Engine Type	Piston
Wingspan	35 ft 6 in (10.82 m)
Seating Capacity	4
Number Built	4, 295
Engine	Lycoming O-360
Horsepower	180 hp
Maximum Takeoff Weight	2, 500 lb (1, 134 kg)