Mercury 350 MAG MPI Horizon, Service Manual

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C1028
Excessive Engine Temperature
Possible Cause Remedy
Water Inlet valve closed (If Equipped). Open valve completely.
Drive belt loose or in poor condition. Replace or adjust belt.
Seawater pickups obstructed. Remove obstruction.
Faulty thermostat. Replace.
Coolant level low in closed cooling system.
Check for cause of low coolant level and repair. Fill
system with proper coolant solution.
Heat Exchanger Cores plugged with foreign
material.
Clean Heat Exchanger.
Loss of pressure in closed cooling system.
Check for leaks. Clean, inspect and test pressure
cap.
Kinked, collapsed, or broken hose. Straighten or replace hose.
Transmission fluid cooler and/or engine oil cooler
plugged with foreign material. Disconnect hoses from coolers and flush out with a
water hose in direction opposite normal water flow.
CA448
Insufficient Engine Temperature
Possible Cause Remedy
Faulty Thermostat. Replace.
CC1029
Low Engine Oil Pressure
Possible Cause Remedy
Insufficient oil in crankcase. Check and add oil.
Excessive oil in crankcase (causing it to become
aerated).
Check and remove required amount of oil. Check for
cause of excessive oil (improper filling, bad fuel
pump).
Engine oil cooler hose kinked causing excessive oil
temperature and thinning of the oil.
Straighten hose or replace, if damaged.
Diluted or improper viscosity oil.
Change oil and oil filter, using correct grade and
viscosity oil. Determine cause for dilution (excessive
idling, faulty fuel pump).