Serpentine Belt Failure Identification - Mercury T6200 TowSport Operation And Maintenance Manual

Serpentine Belt Failure Identification

Appearance
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90-8M0128975 JUNE 2017
eng
Description
Abrasion
Each side of the belt appears
shiny or glazed. Severe
condition: Fabric is exposed.
Pilling
Belt material is sheared off from
the ribs and builds up in the belt
grooves.
Improper install
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.
Cause
Belt is in contact with an object.
Can be caused by improper belt
tension or tensioner failure.
There are a number of causes
including lack of tension,
misalignment, worn pulleys, or a
combination of these factors.
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.
Section 4 - Maintenance
Solution
Replace the belt and
inspect for contact with an
object. Verify the belt
tensioner is functioning.
When pilling leads to belt
noise or excess vibration,
the belt should be
replaced.
The belt life has been
severely limited and
should be replaced
immediately. Ensure all
ribs of the replacement
belt fit into the pulley
grooves. Run the engine.
Then, with the engine off
and battery disconnected,
inspect the belt for proper
installation.
Replace the belt and verify
the alignment of the pulley.
Replace the belt
immediately.
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