Draining; Cleaning; Battery; Multiple Efi Engine Battery Precautions - Mercury MerCruiser Horizon 8.2 ECT Manual

Section 5 - Maintenance
Without sufficient cooling water, the engine, the water pump, and other components will overheat and suffer damage. Provide
a sufficient supply of water to the water inlets during operation.
5. Supply cooling water to the engine.
6. With the engine running, check the hose connections, fittings, and gaskets for leaks. Also observe the engine temperature
gauge to ensure that the engine operating temperature is normal. If the gauge indicates excessive temperature, stop the
engine immediately and determine the cause.
A sudden loss of pressure can cause hot coolant to boil and discharge violently resulting in serious injury from burns. Allow
the engine to cool down before removing the coolant pressure cap.
7. After the engine has cooled completely, recheck the coolant level and add coolant, if necessary.
8. If the reservoir was completely emptied of coolant, a significant amount of air remains in the cooling system. Refill the
reservoir to the "FULL" mark, repeat the warm‑up/cool‑down cycle, and check the coolant level again.
9. Maintain the coolant level in the reservoir at or near the "FULL" mark with the engine cold.

Draining

Contact your authorized Mercury MerCruiser dealer.

Cleaning

Contact your authorized Mercury MerCruiser dealer.

Battery

Refer to specific instructions and warnings accompanying your battery. If this information is not available, observe the following
precautions when handling a battery.
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.
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.

Multiple EFI Engine Battery Precautions

Alternators: Alternators are designed to charge the battery that supplies electrical power to the engine that the alternator is
mounted on. When batteries for two different engines are connected, one alternator will supply all of the charging current for
both batteries. Normally, the other engine's alternator will not be required to supply any charging current.
EFI electronic control module (ECM): The ECM requires a stable voltage source. During multiple engine operation, an
onboard electrical device may cause a sudden drain of voltage at the engine's battery. The voltage may go below the ECM's
minimum required voltage. Also, the alternator on the other engine may now start charging. This could cause a voltage spike in
the engine's electrical system.
In either case, the ECM could shut off. When the voltage returns to the range that the ECM requires, the ECM will reset itself,
and the engine will operate normally. The ECM shuts off and resets itself so quickly that the engine may only seem to have an
ignition miss.
Batteries: Boats with multiengine EFI power packages require each engine be connected to its own battery. This ensures that
the engine's ECM has a stable voltage source.
Battery switches: Battery switches should always be positioned so 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.
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NOTICE
CAUTION
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WARNING
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WARNING
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90-8M0061999 MAY 2012
eng