Charging and Starting Specifications
Description Specification
Alternator model series 8Si 9Si
Alternator output
(regulated)
1800 RPM 37 A 42 A
6000 RPM 85 A 115 A
Regulator voltage set point 14.5 ± 0.25 V
Starter current draw
Under load 170–190 A
No load 60–80 A
Battery Specifications
Required Starting Battery
Description
Specification
Battery type 12‑volt absorbed glass mat (AGM) battery
Rating
USA and Canada (SAE)
800 minimum marine cranking amps (MCA)
with a minimum reserve capacity of 135 RC25 rating
International (EN) 975 minimum cold cranking amps (CCA) with a minimum of 65 ampere hour (Ah)
Special Tools
DMT 2004 Digital Multimeter
91‑892647A01
A
C O
M
m
A
V H z
mV
V
H z TEMP
m A
A
IG
IP
OFF
H z
TEMP
4516
Measures RPM on spark ignition (SI) engines, ohms, amperes, AC and DC
voltages; records maximums and minimums simultaneously, and accurately
reads in high RFI environments.
12 Volt Shunt Tool 91‑889675A01
Connects to the 14 pin engine harness. Turns on the ECM/PCM without the use
of the vessel engine control harness. Used for troubleshooting purpose only.
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.
!
WARNING
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 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.
Charging and Starting System
Page 6B-2 © 2018 Mercury Marine 90-8M0146617 eng JULY 2018
To Next Page
Loading...
Need help?
General
