Engine Roughness - Piper CHEROKEE 180 Owner's Handbook Manual

CHEROKEE 180
SECTION IV
1. Reduce electrical
load.
2.
Alternator
circuit
breakers
-
Check
3.
"Alt"
switch
-
Off (for 30
seconds),
Then On.
If the ammeter
continues
to
indicate no
output,
or alternator
will
not
stay reset, turn off "Alt" switch, maintain
minimum electrical
load
and land
as
soon as
practical.
All
electrical
load is being
supplied
by
the
battery.
ENGINE ROUGHNESS
Engine
roughness
is
usually
due
to carburetor
icing
which
is
indicated by
a
drop
in RPM, and may be accompanied
by
a slight
loss
of
airspeed
or altitude.
If too much
ice
is
allowed to
accumulate,
restoration
of
full
power may
not
be possible,
therefore,
prompt
action
is required.
1.
Carburetor
heat-on
(See Note). RPM
will
decrease
slightly and
roughness will
increase.
Wait for a
decrease in
engine roughness or
an
increase in RPM, indicating ice
removal. If no
change
in
approximately
one
minute,
return carburetor
heat
to
COLD.
If the engine
is
still
rough, try
steps
below.
a.
Mixture
-
Adjust
for
maximum
smoothness.
Engine
will
run rough
if
too rich or too
lean.
b.
Electric Fuel
Pump
-
On
c.
Fuel
Selector
-
Change
to
other
tank to
see
if fuel
contamination is
the
problem.
d.
Engine Gauges
-
Check for
abnormal readings.
If
any
gauge
readings
are
abnormal,
proceed
accordingly.
e. Magneto
Switch
-
"L" then "R",
then
back
to "BOTH".
If operation
is satisfactory
on either magneto,
proceed
on
that magneto at reduced
power,
with
mixture full
rich, to
a
landing
at
the
first
available
airport.
If
roughness
persists, prepare for
a
precautionary landing at pilots
discretion.
761 513
39
720615