ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL
Rev.
7
MM-11-26
Aug
22/16
(14) Service gearbox with oil. See Section 5, Servicing and General Maintenance,
for approved oil and quantity required.
(15) Check all connections for security.
(16) Install main rotor blades.
(17) Track drive belt. See Sections 11-5-E and 11-6-B, Belt Drive System, for
installation and tracking procedure.
(18) Install wraparound cowling.
(19) Complete the "Preflight Control System Check" in Section 12, Flight Controls.
(20) Track main rotor blades. See Section 12, Flight Controls, for tracking
procedure.
11-7
OVERRUNNING CLUTCH & PULLEY ASSEMBLY
A. Clutch and Pulley – Troubleshooting
Problem
Cause
Required Action
Rotor & engine RPM
needles do not split
when power is cut
back.
Overrunning clutch
lockup.
Replace clutch.
Erratic needle
movement - engine
tach seems to climb.
Clutch slipping. Internal
clutch malfunction.
Replace clutch.
Worn pulley grooves
Replace clutch
Clutch end play
exceeding .050 inch.
Internal wear of clutch.
Replace clutch.
Excessive noise on
run-down.
Internal wear.
Replace clutch.
Upper pulley TIR
exceeding .009 inch.
Check while holding
pulley stationary and
rotating gearbox with
clutch disengaged.
Clutch faces worn from
loss of pinion nut
torque.
Replace clutch.
NOTE: If excessive TIR still exists are replacing clutch, the
problem could be internal wear in main rotor gearbox.
Gearbox should be returned to factory or authorized overhaul
facility for inspection.
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