Yanmar 6LY3 series Service Manual page 46

PERIODIC MAINTENANCE
Adjust the V-Belt Tension or Replace V-Belt
Insufficient belt tension will cause the belt to slip,
reduce electrical output and diminish coolant
circulation.
If there is not enough tension in the V-belts
(Figure 4-13, (6)), they will slip and the freshwater
pump (Figure 4-13, (1)) will fail to provide sufficient
coolant flow. Engine overheating and seizure may
result.
Figure 4-13
(1)
(6)
Figure 4-13
1 – Freshwater Pump
2 – Adjuster
3 – Adjuster Bolt
4 – Alternator
5 – Deflection 8-10 mm (Approximately 3/8 in.)
6 – V-Belt
4-14
(2)
(3)
(4)
(5)
0006170
© 2007 Yanmar Marine International
Periodic Maintenance Procedures
Excessive belt tension will cause reduced belt life
and possible damage to the bearing of the
freshwater pump and the alternator.
1. Make sure engine is not running.
2. Check the tension of the V-belts by pressing on
the middle of a belt with your finger
[approximately 98 N (22 lb)].
Specified V-Belt Deflection
For Used V-Belt
For New V-Belt
• New V-Belt refers to a V-Belt which has been
used less than 5 minutes on a running engine.
• Used V-belt refers to a V-belt which has been
used on a running engine for more than
5 minutes.
3. If the V-belt deflection is out of limits, adjust the
V-belt tensions. Loosen the adjuster bolt
(Figure 4-13, (3)) and move the alternator
(Figure 4-13, (4)) to adjust the V-belt tension.
NOTICE: Be careful not to get any oil on the
V-belt. Oil on the belt causes slipping and
stretching. Replace the belt if it is damaged.
6LY3 Service Manual
8-10 mm
(Approximately 3/8 in.)
6-8 mm
(Approximately 5/16 in.)