Piper Cherokee Six - Page 523

PIPER
CHEROKEE
SIX
SERVICE
MANUAL
9-76.
REMOVAL
AND
REPLACEMENT
OF CLUSTER
MOUNTED
INSTRUMENTS.
9-77.
GENERAL.
A
cluster,
located
on
the instrument
panel,
contains
six
individual
instruments.
Removal
of these
instruments
can
be accomplished
by
the following
procedure.
a.
Remove
the
face
panel
by removing
the
screws
from
around
the
perimeter
of
the
panel.
b. With
the
face
panel
removed,
the
clear
plastic
cover
on
the cluster
assembly
will
be
exposed.
Remove
the cover
and cluster
by
removing
the six
mounting
screws.
c.
Remove
the
connection
to
the individual
instrument
to
be removed
and
remove
the
instrument
from
the
cluster
assembly.
d.
Replace
instrument
in the
reverse
order
of removal.
Check
all mountings
and
connections
for
security.
9-78.
EXHAUST
GAS
TEMPERATURE
GAUGE.
(ALCOR)
9-79.
GENERAL.
This
instrument,
which
is commonly
referred
to as
EGT,
is used
to aid
the
pilot in
selecting
the
economical
fuel-air
mixture
for
cruising
flight
at a power
setting
of
75% or
less. It
is a
sensing
device
to monitor
the
fuel-air
mixture
leaving
the
engine
cylinders.
This
gauge
is
adjustable.
If it
is
found
defective
after
checking
with
troubleshooting
chart,
it
should
be
replaced.
If the
leads
to the
gauge
are
defective
in
any
way,
they
should
be
replaced.
When
replacing
leads,
it is
very
important
to
use
the
same
type
and
length
of wire
as the
resistance
of the
leads
is critical
for
the proper
operation
of
this
gauge.
9-80.
REMOVAL
OF
EGT
PROBE
AND
GAUGE
a. Remove
gauge
in the
following
manner.
1.
Disconnect
the
wires
from
the gauge
on
the instrument
panel.
2.
Remove
the four
bolts
securing
the
gauge
to the instrument
panel.
b. Remove
EGT
probe
in
the following
manner.
1.
At the
number
six cylinder
exhaust
stack,
cut the
safety
wire
and unscrew
the
worm
clamp.
2. Carefully
expand
the
clamp
and remove
the probe
from
the
exhaust
stack.
3.
Remove
the ties
holding
the cable
to
the engine
mount
and other
lines.
4.
Pull the
cable
through
the firewall
from
the
engine
compartment.
9-81.
CLEANING
AND
INSPECTION.
Unless
mechanical
damage
is
evident,
broken
glass,
bent
or
broken
pointer,
or broken
case, the
following
checks
should
be performed
before
removing
the
instrument.
a. Remove
probe
from
exhaust
stack and
check for
broken
weld (at tip
end) or
burnt off
end.
Measured
resistance
of probe
should be
.8 ohms.
Clean the
connections
with
steel wool
before
reassembly.
b.
Disconnect
lead wires
at
instrument
and
measure.
Resistance
with
lead
wires
connected
to probe should
be 3.3
ohms.
Clean connections
with steel
wool before
reassembly.
Revised:
9/1/78
INSTRUMENTS