Table of Contents
Advertisement
Charging and Starting System
Battery
Battery Cable Test
This test is used to determine if there is excessive resistance in the battery's positive or negative cables, or if the cable is sized
properly to carry the necessary current needed to crank the engine at the proper RPM.
IMPORTANT: This test must be performed while the key switch is in the "START" position. Ignore any voltage readings taken
without the circuit under load.
Moving parts can cause serious injury or death. Wear eye protection and keep hands, hair, and clothing away from moving
parts when performing tests or checking adjustments on an operating engine.
1.
Perform a load test on the battery following the instructions supplied with the load tester. Ensure that the battery is brought
to a full charge after being tested.
2.
With the key switch in the "START" position, measure the voltage across the battery posts not the cable clamps. Record
the voltage reading. If the voltage is less than 10 VDC, replace the battery.
NOTE: The voltage reading in step 2 is the base voltage. The base voltage reading will be compared to the voltage
readings obtained in the following steps.
3.
With the key switch in the "START" position, measure the voltage from the battery positive post (not the cable clamp) to the
starter solenoid (the bolt where the battery positive cable is connected). Record the voltage reading.
4.
With the key switch in the "START" position, measure the voltage from the starter motor positive terminal to the battery
negative post (not the cable clamp). Record the voltage reading.
5.
If the voltage reading in step 3 was more than 1.0 VDC:
a.
Check the cable connections for tightness and corrosion.
b.
If the cable is tight and not corroded, replace the cable with a larger diameter cable.
6.
If the voltage reading in step 4 was more than 1.0 VDC:
a.
Check the cable connections for tightness and corrosion.
b.
If the cable is tight and not corroded, replace the cable with a larger diameter cable.
Resistance in the cables can cause a voltage drop and limit current to the starter. If corrosion is present, or if the starter is
worn, there may not be enough amperage to turn the starter motor.
NOTE: If the voltage at the starter is less than 11 VDC, the engine may not start.
Original Battery Cable Length and Gauge Shipped with Engine
6–25 (2 and 4‑Stroke 400 cc [24.4 in³] or less)
25–115 (except OptiMax)
125–250 (except OptiMax)
OptiMax/Verado
75/80/90/100/115 EFI FourStroke (2006 and newer)
Battery Cable Size for Outboard Models
IMPORTANT: Only use copper battery cables. Do not use aluminum cables for any outboard marine installations.
•
If longer battery cables are required, the wire gauge size must increase. See chart following for correct wire gauge size.
Page 2B-12
Original Equipment Battery Cable Length/Wire Gauge Size Shipped with Engine
Models (HP)
b
© 2016 Mercury Marine
WARNING
!
a
Cable Length
Wire Gauge Size
2.4 m (8 ft)
2.4 m (8 ft)
3.0 m (10 ft)
3.7 m (12 ft)
3.7 m (12 ft)
a -
Wire gauge size
b -
Battery cable length
2758
90-8M0105568 eng MARCH 2016
8
6
6
4
4
Advertisement
Chapters
Table of Contents
Troubleshooting
