Cessna T188C - Page 235

MODEL 188 & T188 SERIES SERVICE MANUAL
11B-55. FUEL PRESSURE AND WASTEGATE AD- b. Adjust the wastegate one full turn closed to allow
JUSTMENTS. It is recommended
that when making
for slight manifold pressure
variations encountered
any wastegate
or fuel
system adjustments
on T188
in the following
procedures.
aircraft
that the
following steps
be performed in
the c.
Install the unmetered
fuel pressure
test set,
sequence
presented to obtain
correct settings for
fuel P/N SK320-2J.
pressure and wastegate position.
NOTE
NOTE
Run the engine to allow temperatures to
Prior
to performing
the following
steps,
reach
the normal
operating
range before
ensure that
the tachometer, fuel
flow and
proceeding.
manifold pressure gages are indicating
accurately.
d. Adjust
the unmetered fuel pressure
in accor-
dance with the procedures in paragraph 11B-37.
a. Start the engine and very slowly open the throttle e. The following must be adhered to:
until it is full open or until
manifold pressure reaches
1. The low RPM unmetered
fuel pressure and
the pressure shown in
the Maximum Allowable Mani-
only the low unmetered fuel
pressure is to be adjust-
fold Pressure table. Shut the engine down and adjust ed with the fuel pump relief valve adjustment. Fur-
the wastegate position as necessary to obtain the pre- ther, the low RPM unmetered fuel pressure is to be
scribed
pressure with full open throttle.
set
first and not readjusted once
set.
2. The high RPM (2700) unmetered fuel pres-
NOTE
sure is to
be adjusted with the slot
headed needle
valve on the end of the aneroid. At no time during
Use caution not to overboost. All throttle the high unmetered fuel pressure adjustment is the
movements should
be made slowly to allow
fuel pump relief
valve to be adjusted.
adequate time for
the turbocharger to spool
3. At no time
is the fuel pump relief valve ad-
up or down.
justment to be bottomed
out.
CAUTION
A slight
overboosting of manifold
pressure beyond
established maximums
may be en-
countered occasionally
under certain atmospheric
conditions and
is not considered
detrimental to the engine as long as it is momentary. This overboost condition is
corrected by retarding the throttle until the maximum power setting is attained.
However, if overboosting
at full throttle
persists the wastegate
should be adjusted
to lower the maximum
attainable manifold
pressure to the limit
as shown on the
schedule of
maximum allowable manifold
pressure versus
altitude. If the overboost
exceeds 4 inches, the overboost control valve should be replaced.
AN
OVERBOOST EXCEEDING
4 INCHES beyond established
maximums is excessive
and can
result in engine
damage. It is recommended
that overboosting
of this nature be reported
to your Cessna Dealer,
who will be glad to
determine what, if any, corrective
action needs
to
be
taken.
11B-56. EXTREME WEATHER MAINTENANCE. 11B-58. DUSTY AREAS
Refer to Section 11. Refer to Section 11.
11B-57. COLD WEATHER. 11B-59. GROUND SERVICE RECEPTACLE
Refer to Section 11. Refer to Section 16.
11B-21/(11B-22
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