Onan MDKBH Series, Service Manual

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3-5
RESETTING LINE CIRCUIT BREAKERS
If the genset line circuit breaker trips (p. 2-1), or a
circuit breaker in the power distribution panel of the
boat, either a circuit shorted or too many loads were
connected. Note that the genset will continue to run
after a line circuit breaker trips.
If a circuit breaker trips, disconnect or turn off as
many loads as possible and reset the circuit break-
er. If the circuit breaker trips right away, either the
electrical distribution system has a short or the cir-
cuit breaker is faulty. Call a qualified electrician.
If the circuit breaker does not trip, reconnect loads
one-by-one up to a total load that does not overload
the genset or cause the circuit breaker to trip. The
circuit probably has a short if the circuit breaker trips
right away when it is connected.
Electrical equipment must be used and maintained
properly and be properly grounded to cause the line
circuit breakers to trip when short circuits occur.
WARNING
Short circuits in electrical equip-
ment can cause fire and electrical shock leading
to severe personal injury or death. Electrical
equipment and its grounding must be main-
tained properly to protect against short circuits.
COLD TEMPERATURE OPERATION
Drain the heat exchanger (p. 4-12) and muffler be-
fore cold weather sets in if the genset is not being
used. Freezing water can damage the muffler and
the raw water tubes in the heat exchanger.
CARE OF NEW OR RE-BUILT ENGINE
Avoid no-load operation as much as possible during
break-in. Change the oil and oil filter after the first 50
hours of operation (p. 4-4).
EXERCISING THE GENSET
Exercise the genset at least 1 hour every month if
use is infrequent. Run the genset at 1/4 to 3/4 load.
A single exercise period is better than several short-
er periods. Exercising a genset drives off moisture,
re-lubricates the engine, uses up fuel before it be-
comes stale and removes oxides from electrical
contacts. The result is better starting, more reliable
operation and longer engine life.
STORING THE GENSET
Proper storage is essential for preserving top gen-
set performance and reliability when the genset
cannot be exercised regularly and will be idle for
more than 120 days.
Storing the Genset
1. Turn off the genset line circuit breaker (p. 2-1).
2. Change the engine oil and filter and attach a tag
indicating oil viscosity. See ENGINE OIL REC-
OMMENDATIONS (p. 3-1).
3. Crank the engine several revolutions but do not
let it start. This will fill the oil passages with the
new oil.
4. Disconnect the battery cables (negative [ – ]
cable first) from the starting battery and store
the battery according to the battery manufac-
turer’s recommendations. See MAINTAINING
THE BATTERY AND BATTERY CONNEC-
TIONS (p. 4-2).
5. Check coolant level and add as necessary
(p. 4-6). Test the coolant mixture if freezing
temperatures are possible and change if nec-
essary.
WARNING
Hot coolant is under pressure
and can cause severe burns when loosen-
ing the pressure cap. Let the engine cool
before loosening the pressure cap.
6. Drain the heat exchanger and muffler if freezing
temperatures are expected.
7. Clean and lightly oil parts that can rust.
Returning the Genset to Service
1. Check the oil tag on the genset and change the
oil if the viscosity indicated is not appropriate for
the temperatures expected. See ENGINE OIL
RECOMMENDATIONS (p. 3-1).
2. Reconnect the starting battery (negative [
–
]
cable last). See MAINTAINING THE BATTERY
AND BATTERY CONNECTIONS (p. 4-2).
3. Replace the raw water pump impeller if it was
installed more than a year ago (p. 4-10).
4. Perform the maintenance required (p. 4-1),
conduct the pre-start checks and prime the fuel
system.
5. Start and run the genset.
6. Turn on the genset line circuit breaker (p. 2-1)
when ready to power loads.
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