Statis Run-Up Procedures; Baffles; Engine Mount - Cessna 150 STANDARD Service Manual

ible fluid hoses in the engine compartment should be
checked for leaks as follows:
1. Examine the exterior of hoses for evidence of
leakage or wetness.
2. Hoses found leaking should be replaced.
3. Refer to paragraph 11-13 for detailed inspec-
tion procedures for flexible hoses.
11-15C. REPLACEMENT·
a. Hoses should not be twisted on installation.
Pressure applied to a twisted hose may cause fail-
ure or loosening of the nut.
b. Provide as large a bend radius as possible.
c. Hoses should have a minimum of one-half inch
clearance from other lines, ducts, hoses or surround-
ing objects or be butterfly clamped to them.
d. Rubber hoses will take a permanent set during
extended use in service. Straightening a hose with a
bend having a permanent set will result in hose crack-
ing. Care should be taken during removal so that
hose is not bent excessively, and during reinstallation
to assure hose is returned to its original position.
e. Refer to AC 43.13-1, Chapter 10, for additional
installation procedures for flexible fluid hose assem-
blies.
11-15D. STATIC RUN-UP PROCEDURES. In a case
of suspected low engine power, a static RPM run-up
should be conducted as follows:
a. Run-up engine, using take-off power and mix-
ture settings, with the aircraft facing 90° right and
then left to the wind direction.
b. Record the RPM obtained in each run-up posi-
tion.
NOTE
Daily changes in atmospheric pressure,
temperature and humidity will have a
slight effect on static run-up.
c. Average the results of the RPM obtained. Thru
1974 models it should be within 50 RPM
of
2550 RPM.
Beginning with 1975 models it should be within 50
RPM of 2510 RPM.
d. If the average results of the RPM obtained are
lower than stated above, the following recommended
checks may be performed to determine a possible
deficiency.
1. Check carburetor heat control for proper
rigging. If partially open it would cause a slight
power loss.
2. Check magneto timing, spark plugs and igni-
tion harness for settings and conditions.
3. Check condition of induction air filter. Clean
if necessary.
4. Perform an engine compression check. (Re-
fer to engine Manufacturer's Manual).
11-16. BAFFLES.
11-17. The sheet metal baffles installed on the en-
gine directs the cooling air flow around the cylinders
and other engine components to provide optimum
engine cooling. These baffles incorporate rubber-
asbestos composition seals at points of contact with
the engine cowling to help confine and direct cooling
air to the desired area, The baffles, air blast tubes
and air scoops are accurately positioned to maintain
engine COOling efficiency and their removal will cause
improper air circulation and engine overheating.
11-18. CLEANING AND INSPECTION. Engine baf-
fles should be cleaned with a suitable solvent to
remove dirt and oil.
NOTE
The rubber-asbestos seals are oil and grease
resistant but should not be soaked in solvent
for long periods.
Inspect baffles for cracks in the metal and for loose
and/or torn seals, Replace defective parts.
11-19. REMOVAL AND INSTALLATION. Removal
and installation on the various baffle segments is
possible with the cowling removed. Be sure that
any replacement baffles and seals are installed cor-
rectly and that they seal to direct the cooling air in
the correct direction.
11-20, REPAIR. Baffles ordinarily should be re-
placed
if
damaged or cracked. However, small
plate reinforcements riveted to the baffle will often
prove satisfactory both to the strength and cooling
requirements of the unit.
11-21. ENGINE MOUNT.
11-22, The engine mount is composed of sections of
tubing welded together and reinforced with welded
gussets. The purpose of the engine mount is to sup-
port the engine and attach the engine to the airframe.
The engine is attached to the mount with shock-mount
assemblies which absorb engine vibrations, The
engine mount also supports the nose gear shock strut.
11-23. REMOVAL AND INSTALLATION. Removal
of the engine mount necessitates removal of the en-
gine and nose landing gear, followed by removal of
the bolts attaching the engine mount to the fuselage
structure. When installing an engine mount, tighten
mount-to-fuselage bolts to the torque value listed
in figure 11-2. Install landing gear as outlined in
paragraph 5-23. The engine, engine mount and
nose gear may be removed from the aircraft and
then engine and nose gear removed from the mount.
11-24. REPAIR. Perform engine mount repair as
outlined in Section 18. The mount should be painted
with heat-resistant black enamel after welding or
whenever original finish has been removed,
11-25. SHOCK-MOUNT PADS. The rubber and
metal shock-mounts are designed to reduce trans-
mission of engine vibrations to the airframe. The
rubber parts should be wiped with a clean dry cloth.
Inspect metal parts for cracks and excessive wear
due to aging and deterioration. Inspect rubber parts
Change 3
11-11