Under certain operating conditions, it could be dangerous to have the marine propulsion engine stop unexpectantly. Examples of such conditions are: Docking, passing bridge abutments, and locking through a lock-and-dam. Marine engines are usually equipped with various alarm systems which will warn the operator when an abnormal engine operating condition is arising. When an alarm is activated, corrective measures should be taken before the situation becomes an emergency. If corrective measures are not taken in reasonable time, engine damage may result; or if equipped, a corresponding shutoff device will stop the engine.
Each alarm switch is electrically connected to an indicating light, bell or horn. The alarm will continue until the condition is corrected and then the light, bell or horn will turn off.
To silence the bell or horn while repairs are being made, a two-way switch and a red indicator light may be installed. When the alarm is turned OFF, the red indicator light will light.
If the switch is left in the OFF position after the repairs have been made, the red light will indicate the engine is not protected.
Most control panels are equipped with a test switch. By turning the switch ON, all of the indicator lights can be checked for proper operation. Test the indicator lights periodically, replace burned-out light bulbs immediately.
TEST SWITCH AND LIGHTS
All alarms on the engine should be checked twice a year for proper operation by authorized dealer personnel. Abnormal operating conditions must be simulated which could cause engine damage if the tests are incorrectly performed.
ENGINE JACKET WATER TEMPERATURE SWITCH
INLET AIR TEMPERATURE SWITCH - Left Bank
INLET AIR TEMPERATURE SWITCH - Right Bank.
MARINE GEAR OIL TEMPERATURE SWITCH
ENGINE OIL PRESSURE SWITCH
ENGINE JACKET WATER LEVEL SWITCH
ENGINE OIL PRESSURE SWITCH AND OIL PRESSURE ALARM SWITCH
Alarm Systems And Troubleshooting
Listed below are the different alarm systems usually found on an engine. Several causes for the alarm to function are listed, followed by possible corrective measures which should be performed. Additional measures may be required by the operator depending upon the circumstances and conditions present. On multi-engine powered vessels, one engine may be shut down for repairs while proceeding at reduced power on the remaining engine(s).
An authorized AVSpare dealer should analyze major engine problems.
High Engine Jacket Water Temperature Alarm:
This alarm switch is usually installed in the water temperature regulator housing on all engines. If the alarm sounds, check to see if any of the following conditions have occurred.
High Inlet Air Temperature Alarm:
This alarm switch is used on 6.25 inch (159 mm) and 5.4 inch (137 mm) bore V-engines equipped with 85°F (29°C) sea water aftercooling. The switch is mounted in the inlet manifold after the aftercooler. If this alarm sounds, check the following:
High Oil Temperature Alarm:
This alarm is installed on all AVSpare 7200 Series Marine Gear and most V-engines. The switch is located in the oil line between the oil pump and oil strainer or oil filter. If this alarm sounds, check the following:
Low Oil Pressure Alarm:
This alarm switch is usually mounted on the side of the engine block with oil lines connected to the switch. If this alarm sounds, check the following: