EXCESSIVE CONSUMPTION OF LUBEOIL, FUEL, OR WATERYou should suspect engine trouble wheneverexcessive consumption of any of the essential liquidsoccurs. The possible troubles indicated by excessiveconsumption will depend on the system in question.Leakage, however, is one trouble that may be commonto all. Before you start any disassembly, check for leaksin the system in which excessive consumption occurs.TROUBLESHOOTING GASOLINEENGINESThe troubleshooting procedures used for a marinegasoline engine are, in many ways, similar to those fora diesel engine. The two types of engines are quitesimilar with two exceptions, the manner of getting fueland air into the cylinders and the method of ignition.This section deals primarily with the systems thatdiffer in the gasoline and diesel engines. In addition,troubleshooting information is given on the electricalsystems.Even though most electrical maintenance and repairis the responsibility of an Electrician’s Mate, you, as anEngineman, can reduce the amount of electrical troublesby following the correct operating procedures. Mostelectrical system troubles develop from improper use,care, or maintenance.The following information will help you detectelectrical troubles and take corrective action.When a gasoline engine fails to start, one of threeconditions exists. The engine is not free to turn, thestarter does not crank the engine, or the engine cranksbut does not start. Figure 3-44 lists many of theconditions and sources of such difficulties,If the engine will not turn over, some part isprobably seized In this case you should make a throughinspection, which may necessarily include somedisassembly.STARTER DOES NOT RUNIf the starter fails to turn, the trouble can usually betraced to the battery, connections, switch, or startermotor.Symptoms of battery trouble generally occur beforethe charge gets too low to perform the required workBattery failure is normally preceded by a gradual declinein the strength of the battery charge. A dead battery maybe the result of insufficient charging, damaged plates, orimproper starting technique.The generator, used to maintain the charge of thestarting battery, may become defective. The normalsymptoms are a low battery charge when the engine isstarted and a zero or low ammeter reading when theengine is running.The battery must be in good condition to ensure theproper operation of the ignition system. A starter drawsa heavy current from the best of batteries. When thebattery is weak, it will be unable to operate the ignitionsystem satisfactorily for starting because the heavystarting current will drop the voltage to an extremely lowvalue.NOTE: Keep flames and sparks of all kinds awayfrom the vicinity of storage batteries. A certain amountof hydrogen gas is given off from a battery at all times.In confined spaces this gas can form a dangerousexplosive mixture.When you use tools around a battery, be careful notto short circuit the battery terminals. Never use a tool ormetal object to make a so-called test of a storage battery.Keep batteries in exposed locations subject to lowtemperatures fully charged during cold weather. Inextreme cold weather, remove storage batteries andplace them in a warm compartment, if possible.Electrical connections are another possible sourceof trouble if the starter does not turn. All connectionsmust be tight and free from corrosion to providemaximum voltage and amperage from the battery.Battery terminals, since they are more vulnerable tocorrosion, looseness, and burning, are the principalsources of trouble.Burned battery terminals may be caused by a looseconnection, a corroded terminal, or a short circuit.Burning of terminals usually occurs when an engine isbeing started Burning may be indicated by such thingsas smoke, a flash, or a spattering of molten metal in thevicinity of the battery. Usually, the starting motor willcease to turn after these symptoms appear.Switches, electrical relays, or contactors that aredefective or inoperative may be the reason a starter willnot turn. Contactors, being subject to extremely highcurrent, must be maintained in the best possiblecondition. Starting contactors are either manually ormagnetically operated and are designed to be operatedfor only short periods of time.3-43
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