AMMETER - The ammeter should register in the charging
In cold weather the temperature-gauge may fluctuate
range when the engine is running above low idle. If the
in or near the cold range. This indicates the engine is
gauge still registers a discharge as the engine speed is
being overcooled. In these instances the use of radiator
louvers is suggested.
increased, determine the cause.
fails to start, the cranking timer will time out and lock the
An automatic start-stop system ensures that power is
start circuit open, preventing the batteries from being
supplied to a load when the normal power source is
interrupted. The cranking panel is the heart of the system
and consists of the failure warning system and relays to
During the cranking cycle, the safety shutoffs are
start and stop the engine. When a power failure occurs the
inoperative to prevent a low oil pressure shut down. When
system senses the failure, starts the engine and transfers
oil pressure reaches a safe level the safety circuit is armed
the load to standby. When power is restored, it senses
by the arming relay, High water temperature or low oil
pressure will now stop the engine and prevent major
stops the engine. The major use of automatic start-stop
systems is standby electric sets. This discussion is limited
to that application.
If an unsafe engine condition exists, a sending unit
completes the circuit to the safety relay and locking relay.
The remote contacts close when a power failure occurs
The safety relay de-energizes the fuel solenoid and stops
and completes the circuit to the cranking timer and the start
the engine. The locking relay insures that the circuit to the
slave relay. The start slave relay completes the circuit to
safety relay is complete even if the remote contacts open.
the starter motor and the engine begins cranking.
The safety circuit must be reset by moving the start
As the engine starts and increases in speed, the
selector switch to the OFF position. Before restarting any
unit which has been shut down by the safety circuit, the
starts the slave relay. This disconnects the starter motor
cause must be determined and corrected.
circuit and protects the starter from overspeed damage. If
DETERMINING THE CAUSE OF SHUTDOWN
Anytime an engine is shut down by its safety circuit, the
cause must be determined. In some cases the cause will
DO NOT remove the pressure cap of an
be obvious but often an investigation will have to be made.
overheated unit. The coolant is under
Do not put the engine back into service without determining
pressure and relieving this pressure
and correcting the cause of the shutdown.
will cause the coolant to flash into
Serious bums and engine
HIGH WATER TEMPERATURE
damage can result from the escaping
coolant. Pressure in a radiator or surge
Look for the obvious first.
tank may be reduced by pouring warm
water on the top tank to condense the
1. Check for water on the floor from spilled or leaking
2. Check the water temperature gauge for accuracy.
NEVER add cold water to an overheated
3. Check air flow through the radiator.