Mercury MERCRUISER, Service Manual, Page: 323 / 566

Without a seawater pump
a - Alternator pulley
b - Water circulating pump pulley
c - Crankshaft pulley
d - Belt tensioner
e - Power steering pump pulley
Checking
Inspect the drive belt for the following:
•
Excessive wear
• Cracks
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.
mc75130-1
• 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
Belt Tension Gauge SPX BT‑33‑73‑F
Replacing
IMPORTANT: If the belt is removed and is found to be in acceptable condition to use, you must install it in the same direction of
rotation as before.
NOTE: All power packages have a decal on the front of the engine. The decal shows the serpentine belt routing. Refer to the
decal when installing the serpentine belt.
The belt tensioner operates within the limits of movement provided by the cast stops when the belt length and geometry are
correct. If the tensioner contacts either of the cast stops during operation, check the mounting brackets and the belt length.
Loose brackets, bracket failure, accessory drive component movement, incorrect belt length, or belt failure can cause the
tensioner to contact the cast stops. See your authorized MerCruiser dealer for service if these conditions exist.
!
CAUTION
Rapid release of the belt tensioner, or allowing the tensioner to snap back quickly, could cause injury or product damage.
Relieve the spring tension slowly.
1. Use a breaker bar and appropriate socket to relieve the tensioner. Rotate the tensioner counterclockwise away from the
belt until it stops.
a
b
c
d
e
55045
Charging System
90-8M0099748 eng DECEMBER 2015 © 2016 Mercury Marine Page 4C-9