Cessna 150J - Primary Maintenance; Extreme Weather Maintenance; Cold Weather

g. When installing starter, work a non- hardening
gasket paste into both sides of a new gasket, and
position starter and adapter assembly against crank-
case pad.
h. Install three plain washers and hex head nuts on
studs and install bolts through crankcase.
iCAUTION\
Tighten bolts and nuts evenly to prevent
warping adapter cover.
i. Install new Palnuts on cover studs and lock wire
on bolt heads.
j. Connect starter power cable to starter.
11-59. PRIMARY MAINTENANCE. The starting
circuit should be inspected at regular intervals, the
frequency of which should be determined by the
amount of service and conditions under which the
equipment is operated. Inspect the battery and wir-
ing. Check battery for fully charged condition,
proper electrolyte level with approved water and
terminals for cleanliness. Inspect wiring to be sure
that all connections are clean and tight and that the
wiring insulation is sound. Check that the brushes
slide freely in their holders and make full contact on
the commutator. When brushes are worn to one-
half of their original length, install new brushes
(compare brushes with new brushes). Check the
commutator for uneven wear, excessive glazing or
evidence of excessive arcing. If the commutator
is only slightly dirty, glazed, or discolored, it may
be cleaned with a strip of No. 00 or No. 000 sand-
paper. If the commutator is rough or worn, it
should be turned in a lathe and the mica undercut.
Inspect the armature shaft for rough bearing sur-
faces. New brushes should be properly seated when
installing by wrapping a strip of No. 00 sandpaper
around the commutator (with sanding side out) 1-1/4
to 1-1/2 times maximum. Drop brushes on sand-
paper covered commutator and turn armature slowly
in the direction of normal rotation. Clean sanding
dust from motor after sanding operations.
11-60. EXHAUST SYSTEM. The exhaust system con-
sists of a muffler for each bank of cylinders with an
exhaust pipe from each cylinder to the muffler on that
side of the engine. The muffler assemblies are en-
closed in shrouds which captures ram air to be heated
by the exhaust gases in the muffler. This heated air
is used to heat the aircraft cabin and to furnish heated
air for carburetor heat at the engine intake system.
A tail pipe from each muffler routes exhaust gases
overboard through the lower cowling.
11-24
11-61. REMOVAL.
a. Remove engine cowling as required for access.
b. Disconnect flexible ducts from shrouds on muf-
fler assemblies.
c. Disconnect braces from muffler and tail pipe
assemblies.
d. Remove nuts and washers securing the exhaust
stack assemblies to the cylinders.
e. Remove exhaust stack assembly.
11-62. INSPECTION of the exhaust system shall be
thorough because the cabin heating system uses air
heated by the heat exchangers of the exhaust system.
Since exhaust systems of this type are subject to
burning, cracking, and general deterioration from
alternate thermal stresses and vibration, inspection
is very important and should be accomplished every
lOa-hours of operation. In addition, an inspection of
the
exhaust system shall be performed anytime ex-
haust fumes are detected in the cabin area.
a. Remove engine cowling, and loosen or remove
shrouds so that ALL surfaces of the exhaust system
can be visually inspected. Especially check areas
adjacent to welds. Look for exhaust gas deposits
in surrounding areas, indicating that exhaust gas is
escaping through a crack or hole.
b. For a more thorough inspection, or if fumes
have been detected in the cabin, the following inspec-
tion is recommended:
1. Remove exhaust pipe and mufflers.
2. Use rubber expanSion plugs to seal openings.
3. USing a manometer or gage, applyapproxi-
mately 1-1/2 psi (3 inches of mercury) air pressure
while the muffler and each exhaust pipe is submerged
in water. All leaks will appear as bubbles and can be
readily detected.
4. It is recommended that any exhaust pipe or
muffler found defective be replaced with a new part
before the next flight.
c. Install exhaust system.
11-63. INSTALLATION. Reverse procedure out-
lined in paragraph 11-61 to install exhaust system.
Be sure there is one new copper-asbestos gasket
between each exhaust pipe and its mounting pad on
the
cylinder. Make sure clamps attaching mufflers
to exhaust pipes are tight and all air ducts are in-
stalled.
11-64. EXTREME WEATHER MAINTENANCE.
11-65. COLD WEATHER. Cold weather starting is
made easier with the installation of the engine primer
system and ground service receptacle. The primer
system is a manually operated type. Fuel is supplied
by a line from the fuel strainer to the plunger type