8M2000347 Mercruiser RETAINER, Bearing Carrier

Engine Design
G379 Engine
Arrangement and number of cylinders ... V8Bore ... 158.8 mm (6.25 in.)Stroke ... 203.2 mm (8.00 in.)Direction of Rotation (when seen from flywheel end). SAE Standard Rotation ... CounterclockwiseSAE Opposite Rotation ... ClockwiseFiring Order (Injection Sequence). SAE Standard Rotation ... 1-8-5-4-7-2-3-6SAE Opposite Rotation ... 1-4-5-2-7-6-3-8G398 Engine
Arrangement and number of cylinders ... V12Bore ... 158.8 mm (6.25 in.)Stroke ... 203.2 mm (8.00 in.)Direction of Rotation (when seen from flywheel end). SAE Standard Rotation ... CounterclockwiseSAE Opposite Rotation ... ClockwiseFiring Order (Injection Sequence). SAE Standard Rotation ... 1-12-9-4-5-8-11-2-3-10-7-6SAE Opposite Rotation ... 1-4-9-8-5-2-11-10-3-6-7-12G399 Engine
Arrangement and number of cylinders ... V16Bore ... 158.8 mm (6.25 in.)Stroke ... 203.2 mm (8.00 in.)Direction of Rotation (when seen from flywheel end). SAE Standard Rotation ... CounterclockwiseSAE Opposite Rotation ... ClockwiseFiring Order (Injection Sequence). SAE Standard Rotation ... 1-2-11-12-3-4-9-10-15-16-5-6-13-14-7-8SAE Opposite Rotation ... 1-12-11-4-3-10-9-16-15-6-5-14-13-8-7-2Ignition System
The ignition system has five basic components a magneto, (two on earlier G399 Engines) ignition transformers for each cylinder, wiring harness, spark plugs and instrument panel.
Component Location (G399 Engine Illustrated)
(1) Ignition transformer. (2) Spark plug. (3) Wiring harness. (4) Solid state magneto. (5) Magneto drive housing. (6) Timing bolt.Magneto Operation (Fairbanks Morse)
Cutaway View Of Solid State Magneto (Fairbanks Morse) (Typical Illustration)
(1) Timing bolt. (2) Pulser coil assembly. (3) Plate and power board assembly. (4) Distribution board. (5) Capacitor. (6) Alternator housing. (7) Pulser coil (trigger circuit). (8) Pulser rotor. (9) Electronic switch (silicon controlled rectifier). (10) Plug connector.The magneto is a solid state type. It generates (makes) current in the alternator section of the magneto. Low tension current is held in the capacitor and then released. Distribution is then made through the distribution board (4). This system has no contact points, contactors or brushes. There is no spark inside the magneto and only minimum wear. An ignition spark of high tension is made by the transformer to start the air fuel mixture burning under all operating conditions.The alternator makes a voltage as the magnet rotor is turned by the engine through a drive coupling. The alternating current is sent through a rectifier and held in a capacitor (5). A zener diode, on the power board is the regulator of the capacitor voltage for proper ignition.As the pulser rotor (8) moves by each pulser coil (trigger circuit) (7), a voltage is made and sent to the electronic switch (silicon controlled rectifier) (9) for the cylinder ready for ignition. The switch is then turned on and permits the capacitor (5) to release the voltage (discharge). Then the voltage goes through the distribution board (4) and to the transformer. The transformer causes a spark (impulse) of high voltage and low current. This is sent across the electrodes of the spark plug. As the pulser rotor moves by each pulser coil, the same development of spark (impulse) is made.Solid State Magneto (Altronic)
Cross Section Of Solid State Magneto (Altronic)
(3) Alternator. (4) Vent. (5) Speed reduction gears. (6) Pickup coil. (7) Drive tang. (8) Energy storage capacitor. (9) Rotation timer arm. (10) SCR solid state switch. (11) Output connector.
Solid State Magneto (Altronic)
(1) Alternator section. (2) Electronic firing section.The Altronic magneto is made of a permanent magnet alternator section (1) and brakerless electronic firing circuit (2). There are no brushes or distributor contacts.The engine turns magneto drive tang (7). The drive tang turns alternator (3), speed reduction gears (5) and rotating timer arm (9). As the alternator is turned it provides power to charge energy storage capacitor (8). There are separate pickup coils (6) and SCR (silicon controlled rectifier) solid state switches (10) for each engine cylinder. The timer arm passes over pickup coils (6) in sequence. The pickup coils turn on solid state switches (10) which release the energy stored in capacitor (8). This energy leaves the magneto through output connector (11). The energy travels through wiring harness to the ignition coils where it is transformed to the high voltage needed to fire the spark plugs.Instrument Panel
Instrument Panel
(1) Stop switch. (2) Gauge for the oil pressure. (3) Reset button for the magnetic switch. (4) Reset button for the gauge for oil pressure. (5) Gauge for the water temperature.The instrument panel has a magnetic switch, manual stop switch (1), oil pressure gauge (2), and a water temperature gauge (5) which are connected to the magneto. The protection shutoff valve for the gas supply line is also operated by the instrument panel.When the magnetic switch is activated it connects the magneto to ground and stops the engine. This is the normal way to stop the engine. If the water temperature gets too high or if the oil pressure gets too low the magnetic switch is activated.Before a cold engine is started, push in reset button (3) for the magnetic switch and reset button (4) for the gauge for the oil pressure. This prevents the connection of the magneto to ground because of low oil pressure. When the engine starts, normal oil pressure releases the switch from reset position. The gauge switch is then ready to stop the engine when the oil pressure is low.When the gauge switch for the water temperature has correct operation, a hot engine cannot be started.
Oil Pressure Gauge
(4) Reset button for the gauge for oil pressure.When the reset button for the magnetic switch is held in, the gauge switches for the oil pressure and water temperature cannot make connection of the magneto to ground.The protection shutoff valve for the gas line needs manual setting to open it after the engine has stopped.Spark Plugs And Adapters
Spark plugs for this gas engine use two ground electrodes. This permits the spark plug to operate longer before adjustment or replacement is needed.
Spark Plug And Adapter
(1) Cover. (2) High tension wire. (3) Seal. (4) Spark plug adapter. (5) Spark plug.A cover (1) is used over the spark plug adapter. High tension wire (2) goes through cover (1) to the connection (terminal) portion of spark plug (5). This keeps water,