857093 Mercury O-RING

For initial start-up of a new or rebuilt engine, and for start-up of an engine that has been serviced, make provision to shut the engine off should an overspeed occur. This may be accomplished by shutting off the fuel supply and/or the ignition to the engine.
Note: Using the "EMERGENCY STOP" button will shut off both the fuel and the ignition.Do not start the engine or move any of the controls if there is a "DO NOT OPERATE" warning tag or similar warning tag attached to the start switch or to the controls.Ensure that no one will be endangered before the engine is started and when the engine is started.Perform the procedures that are described in this Operation and Maintenance Manual, "Before Starting Engine" (Operation Section).Purging Unburned Gas
Unburned gas in the air inlet and exhaust system may ignite when the engine is started. Personal injury and/or property damage may result.Before starting an engine that may contain unburned gas, purge the unburned gas from the air inlet and exhaust system. Refer to the topic on purging unburned gas in the "Starting the Engine" section.
The following events cause unburned gas to remain in the air inlet and in the exhaust manifold:
Emergency stop
Engine overspeed
The engine control is set to the STOP mode and the gas shutoff valve does not close.
Unsuccessful successive attempts to start the engineUnburned gas may remain in the air inlet and exhaust system after several unsuccessful attempts to start the engine. The unburned gas may increase to a concentration that may ignite during a successive attempt to start the engine.Perform the following procedure to purge the unburned gas:
If the Caterpillar Electronic Technician (ET) is not connected to the engine, connect Cat ET to the engine.
Verify that the value of the "Engine Purge Cycle" parameter is equal to 10 seconds less than the value of the "Crank Cycle" parameter.
Set the engine control to the START mode. The engine will crank for the "Engine Purge Cycle" time. Then, the gas shutoff valve will be energized and the ignition will be enabled. The engine will start.
Continue with your previous procedure.Automatic Starting
When the engine is in the AUTOMATIC mode, the engine can start at any moment. To avoid personal injury, always remain clear of the the engine when the engine is in the AUTOMATIC mode.
If the engine control switch is in the "AUTO" position, the engine will automatically start when the remote start/stop initiate contact closes.Parameters for the Start/Stop Control
Driven Equipment
Start-up is delayed until the switch for the driven equipment indicates that the driven equipment is ready.Purge Cycle
Note: The engine uses an energize-to-run system. The gas shutoff valve must remain energized to supply fuel to the engine.The purge cycle allows any unburned fuel to exit through the exhaust before the engine is allowed to fire.The purge cycle occurs under these conditions:
The gas shutoff valve is de-energized.
The ignition is off.
The engine is cranked.The purge cycle occurs before the crank cycle. The amount of time for the purge cycle is programmable.Cycle Crank Time
The maximum amount of time for activation of the starting motor and the gas shutoff valve for starting is the cycle crank time. The amount of time is programmable. The cycle crank time is only active for automatic starting.Rest Cycle
If the engine does not start within the cycle crank time, starting is suspended for a rest cycle. The amount of time for the rest cycle is equal to the cycle crank time. The rest cycle is only active for automatic starting.Overcrank Time
The overcrank time includes the total purge cycle, the total cycle crank time, and the total rest cycle. These functions are repeated until termination of the overcrank time.If the engine does not start within the overcrank time, the engine control module generates an event code.Manual Starting
Ensure that fuel is supplied to the engine.
Ensure that the driven equipment is unloaded. For generator set engines, ensure that the main circuit breaker is open.
Do not engage the starting motor when flywheel is turning. Do not start the engine under load.If the engine fails to start within 30 seconds, release the starter switch or button and wait two minutes to allow the starting motor to cool before attempting to start the engine again.
Start the engine.The crank terminate speed is programmable. When the engine rpm exceeds the crank terminate speed, the engine control module disengages the starting motor.
Allow the engine speed to stabilize at low idle rpm. Check all pressure gauges. Inspect the engine for leaks and listen for unusual noises. When all systems are normal, the rpm may be increased.
Table 1
Rated RPM And Low Idle RPM
Rated rpm 1000 1200 1400 1500 1800
Low idle rpm 700 900 1000 1000 1200