Onan MDKBH Series, Service Manual

Page: 55 / 90

7-2
INSPECTING DRIVE AND BEARINGS
WARNING
Accidental or remote starting can
cause severe personal injury or death. Before
removing a panel or access door, disconnect
the negative (–) cable at the battery to prevent
the engine from starting.
Remove the back panel (Page 5-1) to inspect the
drive and bearings:
1. Pivot the belt tensioner away from the belt with
a 3/8 inch drive and remove the belt. Examine
the belt for cracks, worn spots and other signs
of deterioration. Replace the belt if necessary
or if it has been in service 5 years or 2000
hours.
2. Remove the drive pulley and coupling as an as-
sembly from the flywheel and then the pulley
from the coupling. Examine the coupling for
wear and deterioration and replace it if neces-
sary. Examine the two split-sleeve bearings in
the pulley hub for wear and scoring and replace
them if necessary.
3. When reassembling, torque the coupling nuts
to 8 lb-ft (12 N-m) and the 4 hub-to-flywheel
bolts to 21 lb-ft (29 N-m).
4. Spin the idler pulley. Replace the bearing if it
does not spin smoothly or is noisy. Replace the
idler assembly if it does not pivot smoothly from
one end of its travel to the other.
5. Spin the generator pulley by hand to determine
if there is any noise, looseness or grinding.
Check for side-to-side and up-and-down loose-
ness of the bearing. If necessary, disassemble
the generator (p. 8-3) to determine the cause of
the looseness or noise. Replace the rotor as-
sembly if it is evident that either bearing has
spun on the shaft. Replace the end bell or
adapter if it is evident that the bearing has spun
in the bore. Replace the bearings if they have
been in service 5 years or 2000 hours.
SERVICE
Generator Pulley
Remove the belt and pulley center bolt and use a
claw-type wheel puller to break the pulley free of the
generator shaft taper. (To keep the rotor from turn-
ing while loosening the pulley bolt, hold the fan bolt
with a wrench.) Torque the center bolt to 45 lb-ft
(60 N-m) when reassembling. Make sure to install
the generator inlet air duct before installing the
pulley.
Generator Inlet Air Duct
Torque the three mounting bolts to 8 lb-ft (12 N-m).
Make sure to install it before installing the pulley.
Tensioner Pulley Assembly
Spin the idler pulley. Replace the bearing if it does
not spin smoothly or is noisy. Replace the idler as-
sembly if it does not pivot smoothly from one end of
its travel to the other. Torque the center pivot bolt
45 lb-ft (60 N-m).
Drive Pulley and Coupling
Remove the drive pulley and coupling as an assem-
bly from the flywheel. Then, if necessary, remove
the 4 coupling nuts on each end to disassemble the
coupling from the hub and the pulley. Examine the
coupling for wear and deterioration and replace it if
necessary. Examine the two split-sleeve bearings in
the pulley hub for wear and scoring and replace
them if necessary.
Torque the coupling nuts to 8 lb-ft (12 N-m) and the
4 hub-to-flywheel bolts to 21 lb-ft (29 N-m).
Flywheel
Remove the drive pulley and coupling as an assem-
bly for access to the flywheel mounting bolts. Scribe
a line across crankshaft and flywheel to make re-
alignment easier when reassembling. The flywheel
will only go on one way because the bolts are
not quite evenly spaced. Proper alignment is
necessary to preserve engine balance and tim-
ing mark.
Torque the 5 mounting bolts to 42 lb-ft (56 N-m)
when remounting the flywheel.
Engine-Generator Adapter
To remove the adapter, first remove the engine-gen-
erator assembly from its mounting (p. 5-2), the gen-
erator (Section 8) from the adapter and the flywheel
from the engine (Section 6). Torque the 6 mounting
bolts to 21 lb-ft (29 N-m) when reassembling.
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