MerCruiser Sterndrive TDI 3.0L User Manual page 105

Appearance
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90-8M0070851 AUGUST 2012
eng
Description
Improper installation
The belt ribs begin separating
from the joined strands. If left
unattended, the cover will often
separate, causing the belt to
unravel.
Misalignment
Sidewalls of the belt may appear
glazed or the edge‑cord may
become frayed and the ribs are
removed. A noticeable noise
may result. In severe cases, the
belt can jump off the pulley.
Chunk‑out
Pieces or chunks of rubber
material have broken off the
belt. When chunk‑out has
occurred, a belt can fail at any
moment.
Uneven rib wear
The belt shows damage to the
side with the possibility of
breaks in the tensile cord or
jagged edged ribs.
Cracking
Small visible cracks along the
length of a rib or ribs.
Cause
Improper belt installation is a
common cause of premature
failure. One of the outermost belt
ribs is placed outside the pulley
groove, causing a belt rib to run
without a supporting or aligning
pulley groove.
Pulley misalignment. Misalignment
forces the belt to kink or twist while
running, causing premature wear.
Chunk‑out can happen when
several cracks in one area move
parallel to the cord line. Heat, age,
and stress are the primary
contributors.
A foreign object in the pulley can
cause uneven wear and cut into
the belt.
Continuous exposure to high
temperatures, the stress of
bending around the pulley leads to
cracking. Cracks begin on the ribs
and grow into the cord line. If three
or more cracks appear in a
three‑inch section of a belt, 80% of
the life is gone.
Section 5 - Maintenance
Solution
The belt should be
replaced immediately.
Ensure all ribs of the
replacement belt fit into
the pulley grooves.
Operate the engine.
Then, with the engine off
and the battery
disconnected, inspect the
belt for proper installation.
Replace the belt and
verify the alignment of the
pulley.
Replace the belt
immediately.
Replace the belt and
inspect all pulleys for
foreign objects or
damage.
Replace the belt
immediately.
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