Serpentine Drive Belt; Checking; Replacing Belt And/Or Adjusting Tension - Mercury MerCruiser 4.3 TKS User Manual

Section 5 - Maintenance

Serpentine Drive Belt

Inspecting the belts with the engine running may cause serious injury or death. Turn off
the engine and remove the ignition key before adjusting tension or inspecting belts.
d
a
With a seawater pump

Checking

1. Inspect the drive belt for proper tension and for the following:
•
•
NOTE: Minor, transverse cracks (across the belt width) may be acceptable. Longitudinal
cracks (in the direction of belt length) that join transverse cracks are NOT acceptable.
•
•
•

Replacing Belt and/or Adjusting Tension

IMPORTANT: If a belt is to be reused, it should be installed in the same direction of rotation
as before.
NOTE: Belt deflection is to be measured on the belt at the location that has the longest
distance between two pulleys.
1. Loosen the 16 mm (5/8 in.) locking nut on the adjustment stud.
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a
b
f
c
e
6116
a - Idler pulley
b - Water circulating pump pulley
c - Crankshaft pulley
Excessive wear
Cracks
Fraying
Glazed surfaces
Proper tension ‑ 13 mm (1/2 in.) deflection, with moderate thumb pressure, on the
belt at the location that has the longest distance between two pulleys.
WARNING
!
d
b
Without a seawater pump
d - Alternator pulley
e - Seawater pump pulley
f - Power steering pump pulley
mc75130-1
90-899883179 OCTOBER 2007
a
f
6117
c