16263 1 Mercury SCREW

Grounding Practices
Properly ground the electrical system for the vessel and the engine. Proper grounding is necessary for optimum engine performance and reliability. Improper grounding will result in uncontrolled or unreliable electrical circuit paths.Uncontrolled or unreliable electrical circuit paths may result in damage to main bearings, crankshaft bearing journal surfaces, and aluminum components. Uncontrolled electrical circuit paths may also cause electrical noise. Electrical noise may degrade the performance of the vessel and of the radio.Connect the starting motor directly to the negative battery terminal. Connect the alternator to the negative battery or negative terminal for the starting motor. The alternator and the starting motor must meet marine isolation requirements.Note: All electrical connections must meet or exceed the American Boat and Yacht Council Standard E-11 or your local Marine Classification Society.Use a bus bar with a direct path to the negative battery terminal for low current components that require a negative battery connection. Connect the bus bar directly to the negative battery terminal.Note: All return paths to the negative battery must be able to carry any likely fault currents.The use of a bus bar ensures that the electronic control module (ECM) and the components connected to the ECM have a common reference point.Refer to Special Instruction, REHS1187, "Marine Engine Electronic Installation Guide" for additional information on grounding procedures.Negative Battery Connection for Multiple Engines
Illustration 1 g03668717
(1) Vessel grounding bus bar
(2) Alternating current (AC) grounding bus bar
(3) Engine negative terminal
(4) Engine
(5) Starter
(6) Battery disconnect switch
(7) Battery Note: Illustration 1 is applicable for wood and fiberglass hulls only.Note: The engine negative terminal (3) must be a clean, metal to metal contact.Install the battery disconnect switches as close as possible to the battery positive (+) but outside of the battery enclosure.Note: If multiple bus bars are used to connect components to the negative battery, a common reference should be provided. All bus bars must be wired together for proper engine synchronization for multiple engine operations.Engine Electrical System
The electrical system has three separate circuits:
Charging circuit
Starting circuit
Low amperage circuitSome of the electrical system components are used in more than one circuit. The following components are used in each of the three circuits:
Battery
Circuit breaker
Ammeter
Battery cablesThe charging circuit is in operation when the engine is running. An alternator generates electricity for the charging circuit. A voltage regulator in the circuit controls the electrical output in order to keep the battery at full charge.
Never move the battery disconnect switch to the OFF position while the engine is operating. Serious damage to the electrical system could result.
If the engine has a disconnect switch, the starting circuit can operate only after the disconnect switch is put in the ON position.The starting circuit is in operation only when the start switch is activated.Both the low amperage circuit and the charging circuit are connected to the same side of the ammeter. The starting circuit is connected to the opposite side of the ammeter.
Never operate the alternator without the battery in the circuit. Making or breaking an alternator connection with heavy load on the circuit can cause damage to the regulator.
Charging System Components
Alternator
Illustration 2 g01363364
Alternator components
(1) Brush holder
(2) Rear frame
(3) Rotor
(4) Stator
(5) Drive end frame
(6) Fan assembly
(7) Slip rings
(8) Rectifier The alternator has three-phase, full-wave, rectified output. The alternator uses brushes to generate electricity.The alternator is an electrical component and a mechanical component that is driven by a belt from engine rotation. The alternator is used to charge the storage battery during engine operation. The alternator is cooled by a fan that is a part of the alternator. The fan pulls air through holes in the back of the alternator. The air exits the front of the alternator and the air cools the alternator in the process.The alternator converts mechanical energy and magnetic energy into alternating current (AC) and voltage. This process is done by rotating an electromagnetic field (rotor) that is direct current (DC) inside a three-phase stator. The alternating current and the voltage that is generated by the stator are changed to direct current. This change is accomplished by a system that uses three-phase, full-wave, rectified outputs. The three-phase, full-wave, rectified outputs have been converted by six rectifier diodes that are made of silicon. The alternator also has a diode trio. A diode trio is an assembly that is made up of three exciter diodes. The diode trio rectifies field current that is needed to start the charging process. Direct current flows to the alternator output terminal.A solid-state regulator is installed in the back of the alternator. Two brushes conduct the current through two slip rings to the field coil on the rotor.Also, a capacitor is mounted in the back of the alternator. The capacitor protects the rectifier from high voltages. The capacitor also suppresses radio noise sources.The voltage regulator is a solid-state electronic switch that controls the alternator output. The voltage regulator limits the alternator voltage to a preset value by controlling the field current. The voltage regulator feels the voltage in the system. The voltage regulator switches ON and OFF many times per second in order to control the field current for the alternator. The alternator uses the field current in order to generate the required voltage output.Starting System Components
Starting Solenoid
A solenoid is a magnetic switch that does two basic operations:
The solenoid closes the high current starting motor circuit with a low current start switch circuit.
The solenoid engages the electric starting motor pinion with the ring gear.
Illustration 3 g00285112
Solenoid
The solenoid has windin