TM 55-2840-241-23
Table 5-1.1 Adjustments to Improve Starting.
Condition
Recommended Adjustments
Excessive lightoff temperature — over
Adjust start/acceleration counterclockwise. If any
810°C (1490°F) with momentary
additional correction is necessary,
peak of one second max at 927°C
adjust start-derichment counterclockwise. (Refer
(1700°F) for a period not to exceed
to subparagraphs (1) and (2) for procedures.)
10 seconds. N1 speed below 20%.
Low lightoff temperature — lightoff
Adjust start/acceleration clockwise. (Refer
temperature below 550°C (1022°F)
to subparagraph (2) for procedure.)
with Nl speed below 20% and slow
acceleration.
High rapid temperature rise with N1
Adjust start/derichment counterclockwise. If any
speed at 25-30 %.
additional correction is necessary
adjust start/acceleration counterclockwise. (Refer
to subparagraphs (1) and (2) for procedures.)
Low lightoff temperature with slow
Adjust start-derichment clockwise. If additional
start — lightoff temperature below
correction is necessary, adjust start
approximately 550°C (1022°F) with
acceleration clockwise. (Refer to subparagraphs
starting time approaching 60
(1) and (2) for procedures.)
seconds (or more ) and N 1 speed
hesitation at 20-33%.
High lightoff temperature — over
Adjust start/acceleration counterclockwise. (Refer
810°C (1490°F) with a momentary
to subparagraph (2) for procedures.)
peak of one second max at 927°C
(1700°F) for a period not to exceed
10 seconds and N1 speed at 35-557.
Low lightoff temperature with slow-to-hung
starts—lightoff
temperature
below
approximately 550°C (1022°F) with
starting time approaching 60 seconds (or
more) and N1 speed hesitation at 35-55%.
Adjust start/acceleration clockwise. (Refer to
subparagraph (2) for procedure.)
(b) Rich (hot) starts may be caused by delayed
ignition, or premature opening of the throttle. How-
ever, hot starts due to high fuel flow are normally
caused by the fuel control. When the fuel control is
suspected, make an adjustment of the start-derich set-
ting as follows:
1 Remove lockwire and loosen adjustment
locknut. (Refer to fig. 5-6.1).
2 Make adjustment, using an Allen wrench.
Turn counterclockwise to lean-out the fuel flow. Make
adjustment in 10° maximum decrements (dots are 10°
apart) and tighten locknut after each setting. Check
starting peak TOT after each setting until satisfactory
starts are made.
3 When desired adjustment is obtained,
secure locknut to Pc filter-fitting with lockwire.
(2) Start/Acceleration Fuel Flow Adjustment
AVIM (Applicable to the Latest Modified Fuel Con-
trols). The start/acceleration fuel flow schedule adjust-
ment maintains the gas producer fuel control starting
schedule within acceptable limits during normal serv-
ice life.
(a) To optimize engine starting, the start-
derichment adjustment should be made in conjunction
with the start/acceleration adjustment. (Refer to table
5-1.1 and figure 5-6.2).
(b) Remove lockwire and make start/acceler-
ation fuel flow adjustment as follows:
Change 14
5-10.3
