845755 Mercruiser RETAINER

Grounding Practices
Proper grounding for the vehicle system and for the electrical system is necessary for proper vehicle performance and reliability. Improper grounding will result in uncontrolled electrical circuit paths and improper grounding will result in unreliable electrical circuit paths. Damage to main bearing and damage to the crankshaft bearing journal surfaces can occur. Uncontrolled electrical circuit paths can also cause electrical noise which may degrade vehicle performance.Use an engine-to-frame ground strap. The engine-to-frame ground strap must have a direct path to the battery. The direct path will ensure proper functioning of the vehicle electrical system and of the engine electrical system. Use a frame to starting motor ground or use a frame to engine ground.Ground wires should be combined at ground studs. The ground studs should be dedicated for ground use only. The engine alternator must be grounded to the negative terminal of the battery. The size of ground wire must be adequate to handle a full current for charging the alternator.Charging System Components
Alternator
Illustration 1 g00317606
Typical alternator components (1) Regulator (2) Bearing (3) Stator winding (4) Bearing (5) Rectifier bridge (6) Field winding (7) Rotor assembly (8) Fan
The alternator should never be operated without the battery in the circuit. The making or the breaking of an alternator connection with a heavy load on the circuit can cause damage to the regulator.
The alternator is driven by a belt from the pulley of the crankshaft. The alternator is three-phase and the alternator is a self-rectifying charging unit. The regulator is part of the alternator.The alternator does not need slip rings or brushes. The rotator assembly is the only part in the alternator that moves. The conductors that carry current are stationary. The following items are conductors: field wire, stator windings, six rectifying diodes and components of the regulator circuit.The rotor assembly has many magnetic poles. An air space is between the opposite poles. The poles have residual magnetism that produces a small magnetic field between the poles. Residual magnetism is similar to permanent magnets. As the rotor assembly begins to turn between the field winding and the stator windings, a small amount of alternating current (AC) is produced in the stator windings. The small amount of current is produced from the small magnetic lines of force. The small magnetic lines of force are made by the residual magnetism of the poles. The alternating current passes through the diodes of the rectifier bridge and the alternating current is then converted into direct current (DC).The current primarily charges the battery and the current primarily supplies the low amperage circuit. The remainder of the current is sent to the field windings (wires around an iron core). This increases the strength of the magnetic lines of force. The amount of alternating current that is produced in the stator windings increases. The increased speed of the rotor assembly increases the current output of the alternator. The increased speed of the rotor assembly also increases the voltage output of the alternator.The voltage regulator is an electronic solid-state switch. The voltage regulator consists of a transistor and stationary parts. The voltage regulator turns on and the voltage regulator turns off in order to control the field current (DC current to the field windings) for the alternator. The needed voltage output is met.Starting System Components
Electric Starting Motor
Illustration 2 g00578758
Components of the electric starting motor (1) Solenoid (2) Pinion (3) Reduction gear (4) Overrunning clutchThe electric starting motor has gear reduction. The electric starting motor is provided with a one-way roller clutch. Major components of the electric starting motor include the following items: motor, overrunning clutch (4) and solenoid (1). The motor generates power. Overrunning clutch (4) transmits the torque of the armature. The overrunning clutch (4) also limits the engine rpm after start-up. The solenoid engages the pinion with the flywheel ring gear. Reduction gear (3) reduces the speeds of the armature and the reduction gear transmits torque to pinion (2) .Reduction Gear
Illustration 3 g00550750
Assembly of reduction gear (1) Armature (2) Pinion (3) Overrunning clutchThe end of the armature shaft has a gear. The gear engages with an internal gear. The gear reduction reduces high motor speed. The gear reduction also transmits higher cranking torque to the pinion shaft.Overrunning Clutch
Illustration 4 g00550752
Components of overrunning clutch (1) Outer race (2) Inner race (3) Spring (4) RollerThe overrunning clutch has rollers. The outer races and the inner races form a groove. The shape of the groove is a wedge. Each roller is located in the groove. Each roller is pressed by a spring. The roller is pressed against the narrower side of the groove by the spring. The rotation of the outer race is transmitted to the pinion. No torque is transmitted from the pinion as the roller moves to the wider side. The action from the wedge is released.Electric Starting Motor Operation
Illustration 5 g00550755
Switch for electric starting motor in ON position (1) Starter switch (2) Starter relay (3) Plunger (4) Field coil (5) Reduction gear (6) Pinion (7) Battery (8) Ring gearCurrent flows from the "SW" terminal of the starting motor relay to the "L" terminal when the switch of the electric starting motor is in the ON position. The "P2" contact closes. Current from the battery flows from the "S" terminal of the magnetic switch to the pull in coil "P". Current from the battery also flows from the "S" terminal of the magnetic switch to the hold in coil "H". The current decreases. The current flows from the "M" terminal to the motor.The plunger is ener