Cessna T188C - 11-59. Internal Timing; 11-60. Installation and Timing to Engine; Removal

MODEL 188
& T188 SERIES
SERVICE
MANUAL
11-58. REMOVAL.
porarily assemble the magneto
halves and capacitor
a. Remove engine cowling in accordance with para- slip terminal and use a timing light to check that the
graph 11-3.
timing marks, visible through
the ventilation plug
b. Tag for
identification
and remove
high tension
holes
are approximately
aligned.
wires
from the
magneto
being removed.
NOTE
WARNING
NOTE
The side
of the magneto
with the
manufac-
The magneto
is not internally grounded
when turer's
insignia has a red timing mark
and
the switch wire is disconnected. Remove the side opposite to the insignia has a black
the high tension wires from
magneto or dis-
timing mark viewed through
the vent plug
connect spark plug leads
from the spark
holes. The distributor
gear also has a red
plugs.
timing mark and
a black timing mark. These
marks are used for reference only when in-
c. Disconnect switch wire from condenser terminal stalling magneto on the engine. Do not place
at magneto. Tag wire for identification so it may be red and black lines together on the same side.
installed correctly.
d. Rotate propeller in direction of normal rotation c. Whenever the large distributor gear and rotor
until
No. 1 cylinder is coming up
on its compression gear
have been disengaged, they must
be engaged
stroke.
with
their timing
marks aligned for
correct rotation.
Align
the timing
mark on the
rotor gear with
the
NOTE
"RH" on the
distributor
gear. Care
must be taken
to keep these two gears meshed in this position until
To facilitate the installation of a replacement the magneto halves are assembled.
magneto, it is good practice to position the
crankshaft at the advanced
firing angle for
11-60. INSTALLATION
AND TIMING TO ENGINE.
No. 1 cylinder during step
"d." Any standard The
magneto must be installed with
its timing marks
timing
device or method can be used,
or if the correctly
aligned and with the number
one cylinder
magneto being
removed is correctly
timed to
on
its compression
stroke with number
one piston
at
the engine, the crankshaft
can be rotated to a
its advanced firing position.
Refer to paragraph 11-8
position at which the breaker
points will be
for the advanced firing position
of number one piston.
just opening to fire No. 1 cylinder.
e. Remove magneto retainer clamps, nuts and
washers
and pull
magneto from
crankcase mounting
The magneto is
grounded through
the magneto
pad.
toggle
switch, therefore,
any time
the switch
(primary) wire is disconnected from the mag-
NOTE
neto, the
magneto is in a switch
ON or HOT
condition.
Before turning
the propeller
by
As
the magneto is removed from
its mount- hand,
remove the high tension wires
from the
ing, be sure
that the drive coupling rubber
magneto
or disconnect all spark plug
leads to
bushing
and retainer
do not become
dislodged
prevent accidental
firing
of the engine.
from the gear hub and fall into the engine.
To locate the compression stroke of number one cy-
NOTE
linder,
remove
the
lower
spark
plugs
from each
cy-
linder except number one cylinder. Remove the top
For
inspection
of impluse
coupling
plug from
number
one cylinder.
Place
thumb
of one
on
aircraft
serials
18800001
THRU
hand
over
the
number
one
cylinder
spark
plug
hole
18801707,
refer
to
Cessna
Single-
and
rotate the
crankshaft
in the direction
of normal
engine
Service
Letter
SE74-21,
rotation
until
the compression
stroke
is indicated
by
dated
September
27,
1974.
positive
pressure
inside
the
cylinder
lifting
the thumb
off the spark plug hole. After the compression stroke
11-59. INTERNAL
TIMING.
is
obtained, locate
number one piston
at its advanced
a.
Whenever
the gear on
the rotor
shaft or the
cam
firing position.
Locating
the
advanced
firing position
(which also
serves as the
key for the gear)
has been
of number
one cylinder may
be obtained by
use of a
removed,
be sure that
the gear and
cam are installed
timing
disc and pointer,
Timrite, protractor
and
so the timing
mark on the
gear aligns with
the "0"
piston locating
gage or external
engine timing
marks
etched
on the
rotor shaft.
alignment.
b.
When replacing
breaker assembly
or adjusting
contact
breaker
points,
place a
timing pin
(or 0.
093
NOTE
inch 6-penny nail) through the timing hole in the bot-
tom of the
magneto next to the flange and
into the External
engine timing marks are located
on
mating hole in
the rotor shaft. Adjusting contact
a bracket
attached to the starter adapter,
breaker points so they are just starting to open in with a timing mark on the alternator drive
this
position will give the correct
point setting. Ter-
pulley as the reference
point.
11-19