
2. Remove the belt from the idler pulley and slowly relieve the tension on the breaker bar.
Standard cooling shown, closed cooling similar
a -
Belt tensioner
3. Inspect the belt for damage and replace as necessary.
4. Route the belt according to the diagram on the decal.
5. Carefully release the tensioner and ensure that the belt stays positioned properly.
6. Check the belt tension.
NOTE: Proper tension is a measurement of deflection with moderate thumb pressure on the belt at the location that has
the longest distance between two pulleys.
Description
Deflection
13 mm (½ in.)
Troubleshooting
Before You Begin
!
WARNING
An operating or charging battery produces gas that can ignite and explode, spraying out sulfuric acid, which can cause
severe burns. Ventilate the area around the battery and wear protective equipment when handling or servicing batteries.
!
WARNING
Recharging a weak battery in the boat, or using jumper cables and a booster battery to start the engine, can cause serious
injury or product damage from fire or explosion. Remove the battery from the boat and recharge in a ventilated area away
from sparks or flames.
IMPORTANT: The charging system may be damaged by:
•
Reversed battery cables
•
Running the engine with the battery cables disconnected
•
An open circuit, such as a broken wire or loose connection
Before proceeding with the tests in this section, perform the following checks to eliminate possible problem areas.
1. Check the charge and physical condition of the battery and battery cables. The battery must be at least 75 percent (1.230
specific gravity) charged to obtain valid test results. Ensure that the battery is fully charged before testing the system.
NOTE: An undercharged battery can result from excessive current draw from excessive accessory power loads or by
extended operation at low speeds.
2. Inspect the charging system wiring for damage or corrosion. Ensure that all connections are secure and clean.
3. Check the alternator drive belt for proper tension, excessive wear, cracks, fraying or glazed surfaces. Replace if necessary.
Charging Output Tests
1. Check the drive belt condition and tension.
2. Check battery charge and condition.
3. Connect the digital multi‑tester (DMT) leads directly to the battery posts.
a
54989
Charging System
Page 4C-10
© 2016 Mercury Marine
90-8M0099748 eng DECEMBER 2015
Summary of Contents for MERCRUISER
Page 2: ......
Page 6: ...90 8M0099748 eng DECEMBER 2015 2016 Mercury Marine Page iv...
Page 12: ...General Information Notes Page 1A 6 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 70: ...Maintenance Notes Page 1C 54 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 96: ...Troubleshooting Notes Page 1D 26 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 156: ...Installation Notes Page 2B 52 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 202: ...Engine Disassembly Notes Page 3A 46 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 286: ...Engine Troubleshooting Notes Page 3C 14 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 314: ...Waste Spark System Notes Page 4B 8 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 330: ...Charging System Notes Page 4C 16 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 404: ...MPI ECT Fuel System Notes Page 5A 34 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 424: ...All Models Notes Page 6A 20 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 448: ...Models with Closed Cooling Notes Page 6C 20 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 462: ...Water Flow Diagrams Notes Page 6D 14 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 474: ...Important Information Notes Page 7A 12 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 477: ...Manifolds and Elbows Notes 90 8M0099748 eng DECEMBER 2015 2016 Mercury Marine Page 7B 3...
Page 538: ...Compact Hydraulic Steering Notes Page 8B 12 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 558: ...Notes Color Diagrams Page 10A 2 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 559: ...Notes Color Diagrams 90 8M0099748 eng DECEMBER 2015 2016 Mercury Marine Page 10A 3...
Page 565: ......