Precautions - Mercury MerCruiser MCM 454 Mag MPI Service Manual

SERVICE MANUAL NUMBER 23

Precautions

The following requirements must be observed:
Index
90-861326--1 MARCH 1999
Downloaded from https://needmanual.com/
Before removing any ECM system component, disconnect the negative battery cable.
Never start the engine without the battery being solidly connected.
Never separate the battery from the on-board electrical system while the engine is run-
ning.
Never separate the battery feed wire from the charging system while the engine is run-
ning.
When charging the battery, disconnect it from the boat's electrical system.
Ensure that all cable harnesses are connected solidly and that battery connections are
thoroughly clean.
Never connect or disconnect the wiring harness at the ECM when the ignition is switched
ON.
Before attempting any electric arc welding, disconnect the battery leads and the ECM
connector(s).
When steam cleaning engines, do not direct the steam cleaning nozzle at ECM system
components. If this happens, corrosion of the terminals or damage of components can
occur.
Use only the test equipment specified in the diagnostic charts, since other test equip-
ment may either give incorrect results or damage good components.
All voltage measurements using a voltmeter require a digital voltmeter with a rating of 10
megohms input impedance.
MULTI-PORT FUEL INJECTION DESCRIPTIONS AND SYSTEM OPERATION
Page 5B-13