Oil Cooler; Carburetor; Induction Air System; Filter Adapter Installation - Cessna 177 SERIES Service Manual

11-42. INSTALLATION.
a. Start and run engine until the oil and cylinder
a. Using a good grade of gasket sealant, install a
head temperatures are in the normal operating range.
new gasket on accessory housing adapter mount pad.
b. Check the magnetos for proper operation in ac-
Note that one side of the gasket is marked ENGINE
cordance with paragraph 11-64.
SIDE; this side of the gasket must be installed toward
c. Clear the engine by advancing the rpm to approxi-
the engine.
mately 1000, then retard the throttle to the idle posi-
b. Install adapter on mounting pad and install bolts,
tion. The engine rpm should stabilize at 600±25.
If
washers and nut.
Use lockwashers next to bolt heads not, adjust the idle speed screw IN to increase and
and nut.
OUT to decrease rpm.
c. Tighten bolts and nut to 75 lb-in.
d. Install oil temperature bulb in adapter.
NOTE
e. Install filter assembly in accordance with para-
graph 11-38.
An engine should idle smoothly, without
f. Install any components removed for access.
excessive vibrations.
The idle speed
should be high enough to maintain idling
11-43. OIL COOLER.
oil pressure and to preclude any possi-
bility of engine stoppage in flight when
11-44. DESCRIPTION.
The external oil cooler is the throttle is closed.
mounted on the firewall. Flexible hoses carry the
oil to and from the cooler. Cooling air for the cooler
d. After the idle speed has stabilized (600±25 rpm),
is ducted from the upper right engine baffle to the
move the mixture control slowly toward the IDLE
shroud covered oil cooler.
Exhaust air from the
CUT-OFF position and observe the tachometer for
cooler is discharged into the engine compartment.
any minute change during this manual leaning proce-
At each engine oil change, drain the oil cooler.
dure.
e. Quickly return the mixture control to the FULL
11-45. ENGINE FUEL SYSTEM.
RICH position before the engine stops.
f. A momentary increase of approximately 25 rpm
11-46. DESCRIPTION.
A single barrel, float-type, while slowly manually leaning the mixture is most
up-draft carburetor is installed on the engine. The desirable, an increase of more than 25 rpm indicates
carburetor is equipped with a manual mixture control
a rich idle mixture and an immediate decrease in rpm
and an idle cut-off. For repair and overhaul of the
(if not preceded by a momentary increase) indicates
carburetor refer to the manufacturer's overhaul and a lean idle mixture.
repair manual.
g. If the idle mixture is too rich, turn the idle mix-
ture adjustment center screw one or two notches in a
11-47. CARBURETOR.
clockwise direction as viewed from the aft end of the
unit, then repeat steps "d" through "f."
11-48. REMOVAL AND INSTALLATION.
a. Pull fuel shut-off valve control to the OFF posi-
NOTE
tion.
b. Remove engine cowling in accordance with para-
After each adjustment to the idle mixture, run
graph 11-3. engine up to approximately 1800 rpm to clear
c.
Drain fuel from strainer and lines with strainer the engine of excess fuel and obtain a correct
drain control.
idle speed.
d. Disconnect throttle and mixture controls at car-
buretor. Note the EXACT position, size and number
h. If the idle mixture is too lean, turn the idle mix-
of washers and spacers for reference on reinstalla-
ture adjustment center screw one or two notches in a
tion.
counterclockwise direction as viewed from the aft end
e. Disconnect and cap or plug the three fuel lines
of the unit, then repeat steps "d" thru "f."
at carburetor.
i. This method of adjustment will give the desired
f. Remove induction airbox in accordance with
idle rpm. If the adjustments do not remain stable,
paragraph 11-53.
check the throttle and mixture linkage for evidence of
g. Remove nuts and washers attaching carburetor
wear and improper rigging.
Any looseness of the
to intake manifold and remove carburetor.
throttle and mixture linkage will cause erratic idling.
h. Reverse the preceding steps for reinstallation.
In all cases, allowance should be made for the effect
Use new gaskets between carburetor, intake mani-
of weather condition upon idling adjustment. The re-
fold and induction airbox.
lation of the aircraft to the prevailing wind direction
i. Rig throttle and mixture controls in accordance will have an effect on the propeller load and engine
with paragraphs 11-69 and 11-70. Check carburetor rpm. It is advisable to make idle adjustments with
throttle arm to idle stop arm attachment for security the aircraft crosswind.
and proper safetying at each normal engine inspection
in accordance with figure 11-5. 11-50. INDUCTION AIR SYSTEM.
11-49. IDLE SPEED AND MIXTURE ADJUSTMENTS.
11-51. DESCRIPTION. Ram air to the engine enters
Since idle rpm may be affected by idle mixture ad-
the induction airbox through the induction air filter.
justment, it may be necessary to readjust idle rpm
From the induction airbox the air is directed to the
after setting the idle mixture.
inlet of the carburetor, mounted on the lower side
of the engine oil sump, through the carburetor to the
11-18 Change 3