Mercury 2.8 Diesel Operation & Maintenance Manual page 103

Section 4 - Maintenance
In either case, the ECM could shut off. When the voltage returns to the range that the ECM requires, the ECM will reset itself.
The engine will now run normally. This ECM shut down usually happens so fast that the engine just appears to have an ignition
miss.
Batteries: Boats with multi‑engine Electronic Control power packages require each engine be connected to its own battery,
ensuring that the engine's Electronic Control Module (ECM) has a stable voltage source.
Battery Switches: Battery switches should always be positioned so that each engine is operating off of its own battery. Do not
operate engines with switches in both or all position. In an emergency, another engine's battery can be used to start an engine
with a dead battery.
Battery Isolators: Isolators can be used to charge an auxiliary battery used for powering accessories in the boat. They should
not be used to charge the battery of another engine in the boat unless the type of isolator is specifically designed for this
purpose.
Generators: The generator's battery should be considered another engine's battery.
90-8M0113987 DECEMBER 2015 Page 95
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