99173 1 Mercury GASKET, DRIVE SHAFT HOUSING TO PLATE

Grounding Practices
Proper grounding is necessary for optimum engine performance and reliability. Improper grounding will result in uncontrolled electrical circuit paths and in unreliable electrical circuit paths.Uncontrolled electrical circuit paths can result in damage to main bearings, to crankshaft bearing journal surfaces, and to aluminum components. Uncontrolled electrical circuit paths can also cause electrical activity that may degrade the engine electronics and communications.Ensure that all grounds are secure and free of corrosion.The engine alternator must be grounded to the negative "-" battery terminal with a wire that is adequate to carry the full charging current of the alternator.For the starting motor, do not attach the battery negative terminal to the engine block.Ground the engine block with a ground strap that is furnished by the customer. Connect this ground strap to the ground plane.Use a separate ground strap to ground the negative "-" battery terminal for the control system to the ground plane.If rubber couplings are used to connect the steel piping of the cooling system and the radiator, the piping and the radiator can be electrically isolated. Ensure that the piping and the radiator are continuously grounded to the engine. Use ground straps that bypass the rubber couplings.
This engine is equipped with a 24 volt starting system. Use only equal voltage for boost starting. The use of a welder or higher voltage will damage the electrical system.
Always disconnect the power when you are working on the engine's electronics.Charging System Components
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.
Alternator
Illustration 1 g00285111
Alternator components (typical example)
(1) Regulator
(2) Roller bearing
(3) Stator winding
(4) Ball bearing
(5) Rectifier bridge
(6) Field winding
(7) Rotor assembly
(8) Fan The alternator is driven by a belt from an auxiliary drive at the front right corner of the engine. This alternator is a three-phase, self-rectifying charging unit. Regulator (1) is part of the alternator.This alternator design has no need for slip rings or brushes, and the only part that moves is rotor assembly (7). All conductors that carry current are stationary. The conductors are field winding (6), stator windings (3), six rectifying diodes, and the regulator circuit components.Rotor assembly (7) has many magnetic poles. Air space is between the opposite poles.The poles have residual magnetism that produces a small amount of magnetic lines of force between the poles. As rotor assembly (7) begins to turn between field windings (6) and stator windings (3), a small amount of alternating current (AC) is produced in the stator windings. This current is from the small magnetic lines of force that are made by the residual magnetism of the poles. This AC is changed to direct current (DC). The change occurs when the current passes through the diodes of rectifier bridge (5). Most of this current completes two functions. The functions are charging the battery and supplying the low amperage circuit. The remainder of the current is sent to field windings (6) which are wires around an iron core. The flow of DC through the field windings increases the strength of the magnetic lines of force. These stronger lines of force increase the amount of AC that is produced in stator windings (3). The increased speed of rotor assembly (7) also increases the current and voltage output of the alternator.Voltage regulator (1) is a solid-state, electronic switch. The regulator senses the voltage in the system. The regulator opens and the regulator closes the field current many times in one second in order to control the field current to the alternator. The output voltage from the alternator supplies the needs of the battery and the other components in the electrical system. The rate of charge cannot be adjusted.Other Components
Circuit Breaker
The circuit breaker is a switch that opens the battery circuit if the current in the electrical system goes higher than the rating of the circuit breaker.A heat-activated metal disc with a contact point completes the electric circuit through the circuit breaker. If the current in the electrical system gets too high, the metal disc gets hot. This heat causes a distortion of the metal disc. The disc opens the contact in order to break the circuit.
Find and correct the problem that causes the circuit breaker to open. This will help prevent damage to the circuit components from too much current.