Cessna T188C - Page 200

MODEL 188 & T188 SERIES SERVICE MANUAL
11A-46. REMOVAL. e. Tag and disconnect all lines and fittings attach-
ed to the fuel pump.
NOTE
NOTE
Plug or
cap all disconnected
lines
and fittings.
Plug or cap all disconnected lines, hoses
a.
Disconnect
the fuel
injection
lines at the
fuel dis-
and
fittings.
charge nozzles. Remove nozzles with a 1/2 inch deep
well socket
wrench.
f.
Remove
the shroud surrounding
the fuel
pump.
g. Remove the nuts and washers attaching the fuel
11A-47. CLEANING
AND INSPECTION.
To clean pump
to the engine.
nozzles,
immerse
in clean
solvent
and use
compress-
h. Remove
fuel
pump and
gasket.
ed air to
dry them. When
cleaning, direct
air through
the nozzle
in the direction opposite
of normal fuel flow.
WARNING
Do not remove the nozzle shield or distort it in any
way. Do not
use a wire or other
metal object
to clean
Residual
fuel draining from
lines and
hose
the orifice
or metering
jet.
After cleaning,
check
the
constitutes
a fire hazard.
Use
caution to
shield
height from
the hex
portion
of the nozzle.
The
prevent
accumulation
of fuel when
lines
or
bottom of the shield
should be approximately
1/16 hoses
are disconnected.
inch above the hex portion of the nozzle.
i. If a replacement pump is not being installed im-
11A-48.
INSTALLATION.
mediately,
a temporary cover
should be installed
on
a.
Install
nozzles
in the cylinders
and tighten
to
a
the fuel
pump
mount pad.
torque
value
55 to
65 lb-in.
b. Connect
the fuel lines at discharge
nozzles.
11A-51. INSTALLATION.
c. Check installation
for crimped lines, loose
fit- a. Position a
new gasket and fuel pump on
the
tings, etc.
mounting studs with fuel
pump inlet to the left. Be
sure pump drive
aligns with
drive in the
engine.
11A-49. FUEL INJECTION
PUMP. The fuel pump
b. Secure pump to engine
with plain washers, in-
is a positive-displacement,
rotating vane
type, con-
ternal tooth
lock washers
and nuts. Tighten
nuts
nected
to the accessory drive
section of the
engine. evenly.
Fuel enters the pump at the swirl well of the pump c. Install cooling shroud on fuel pump.
vapor separator. Here, vapor is separated by a d. Install all fittings and connect all lines.
swirling motion so that only liquid fuel is fed to the e. Install the flexible ram air tube on the air horn
pump. The vapor is
drawn from the top center of
the of the fuel pump
shroud and install clamp.
swirl well by a
small pressure jet of fuel and is
fed f. Replace the alternator
drive belt and tighten
the
into the vapor
return line, where it is returned
to the nuts on the
adjusting arm so that the drive
belt has
aircraft fuel system.
Since the pump is
engine-driven, proper
tension. Refer to Section
16.
changes
in engine speed affects total
pump flow pro-
g. Inspect complete installation.
portionally. A check valve allows the auxiliary fuel
pump pressure
to bypass
the engine-driven
fuel
pump
11A-52.
ADJUSTMENT.
During
the
1967 model
for starting, or in the event
of engine-driven fuel
year an adjustable orifice is
added to the engine-
pump failure. The pump
supplies more fuel than is
driven fuel pump so that
the pressures for the full
required by the engine; therefore,
a spring-loaded,
throttle position may be obtained.
This adjustable
diaphragm type relief
valve is provided, with an ad-
orifice allows the exact desired
pressure setting and
justable
orifice installed
in the fuel passage
to the
eliminates
changing of the
fixed orifice to
obtain the
relief valve
to maintain desired fuel pressure
for en- pressure required.
The adjustable orifice
applies
gine power setting.
The adjustable orifice allows
the to the FULL throttle
setting only. Adjustment of
the
exact desired
pressure setting at full throttle.
The idle position
is still obtained through the relief
valve.
fuel
pump is equipped with a manual
mixture control This new
pump is used as spare parts
and is furnish-
to provide
positive mixture
control throughout
the
ed if a new pump
is ordered.
Adjustment of
the pumps
range required by the
injection system. This control
not incorporating the adjustable
orifice is still per-
limits output of the pump from full rich to idle cut-off. formed as outlined in Cessna Service Kit No. SK320-
Non-adjustable
mechanical stops are located
at these 2J, using the
pressures specified in paragraph
11A-8.
positions.
To adjust
the pump incorporating the adjustable
orifice
proceed as follows:
11A-50.
REMOVAL.
a. Place full shut-off
valve in OFF position and
a. Remove engine cowling
as required in accor-
mixture control in IDLE CUT-OFF position. dance with paragraph 11A-3.
b. Remove
upper cowling
section
in accordance
with paragraph 11A-3. NOTE
c. Loosen
the clamps
and slide the
flexible tubes
free of the horns on the fuel
pump shroud to gain ac-
Inspect the slot-headed
adjustable orifice
cess to the fuel lines. needle valve (located just below the fuel
d. Remove the alternator
drive belt.
11A-16