ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL
Rev.
7
MM-4-27
Aug
22/16
E. If servicing after draining the engine oil system, ground run the engine in accordance
with the applicable rotorcraft flight manual/pilots operating manual. After the ground run, check
the oil level and service as required.
4-8. Draining – Engine Oil System
A. Place a suitable container under the drain plug in the bottom of the engine sump.
B. Remove the drain plug or open the drain valve and allow oil to drain sump.
C. Reinstall the drain plug and safety wire or close the drain valve after draining the oil.
D. Place a suitable container under the lower oil line connection of the engine oil cooler.
E. Disconnect the oil line from the cooler and drain the oil from the oil cooler and line.
F. Reconnect the oil line.
G. If the helicopter is equipped with an auxiliary engine oil cooler, place a suitable
container under the oil cooler.
H. Disconnect the oil line from the oil cooler and drain the oil from the oil cooler and oil
line.
I.
Reconnect the oil line.
4-9. Overrunning Clutch
(Figure 4-1, View G)
4-10. Servicing – Overrunning Clutch
NOTE
Refer to Table 4-1 for system capacity and approved oil. An alternate
servicing procedure is described in step F.
A. Rotate the upper pulley/overrunning clutch until the service plugs in the clutch are in
the horizontal and vertical positions. Continue to rotate the upper pulley/overrunning clutch until
one of the horizontal filler plugs is slightly above horizontal.
B. Remove the filler plugs that are in the above horizontal and beyond vertical positions.
C. Slowly rotate the upper pulley/overrunning clutch so that the open filler ports move
towards the horizontal and vertical position.
D. The overrunning clutch is properly serviced when the oil starts to drain from the open
filler port as the port reaches the horizontal position.
E. Add oil to the overrunning clutch until oil starts to drain from the filler port in the
horizontal position.
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