Yanmar 4JH45 Operation Manual page 72

PERIODIC MAINTENANCE
1
Figure 4
Note: 4JH110 shown.
1. Remove the belt cover.
2. Check the belt by pushing on the
middle of the belt (Figure 4, (1)) with
your finger. (Pressed by 100 N)
With proper tension, the belt should
deflect 8 to 9 mm.
Note: Check the tension of the
V-ribbed belt after operating the
engine at idle for 5 minutes.
3. Loosen the 3 bolts of alternator
(Figure 4, (2) (3) (4)).
4. Screw in the adjusting bolt
(Figure 4, (4)) and move the alternator
to adjust the belt tension properly.
5. Tighten the 3 bolts of the alternator.
6. Install the belt cover.
Inspecting V-Ribbed Belt
1. Visually check the belt for excessive
wear, frayed cords, etc.
If any defects are found, replace the
V-ribbed belt.
2. Check that the belt fits properly in the
ribbed grooves.
66
2 4
3
056901-00X00
NOTICE
Confirm by hand that the belt has not
slipped out of the grooves on the bottom
of the pulley.
Checks on the rib side of the belt are
considered acceptable. If the belt has
chunks missing from the ribs, it should
be replaced.
Figure 1
Figure 5
Figure 2
CORRECT
INCORRECT
Figure 6
Inspecting and Adjusting
Intake/Exhaust Valve Clearance
Proper adjustment is necessary to
maintain the correct timing for opening and
closing the valves. Improper adjustment
will cause the engine to run noisily,
resulting in poor engine performance and
engine damage. Consult authorized
Yanmar Marine dealer or distributor to
adjust the intake/exhaust valve clearance.
JH Series Operation Manual
037421-00X00
037422-00EN00