813859 Mercury GASKET (200)

Aftercooler coolant temperature - This gauge indicates the temperature of the coolant in the aftercooler system. Two methods of aftercooling are available. The separate circuit aftercooler operates at a temperature that is lower than the jacket water aftercooler. Determine the method of aftercooling in order to verify the gauge reading.
If no oil pressure is indicated, STOP the engine. The engine will be damaged from operating without oil pressure.
Engine oil pressure - This gauge indicates the pressure of the engine oil. This pressure will be highest after a cold engine is started. The pressure will decrease as the engine warms up. The pressure will increase when the engine rpm is increased. The pressure will stabilize when the engine rpm and temperature are stable.
Engine Oil filter differential pressure (restriction) - This gauge indicates the difference in pressure between the inlet side and the outlet side of the engine oil filters. As the oil filter elements become plugged, oil filter differential pressure will increase.If the load is stabilized but the engine oil pressure fluctuates, perform the following procedure:
Remove the load.
Reduce the engine speed to low idle rpm.
Check the oil level. Maintain the oil level between the "ADD" and "FULL" marks on the "LOW IDLE" side of the oil level gauge (dipstick).
Inspect the lubrication system for leaks.
Engine oil temperature - This gauge indicates the temperature of the engine oil.Engine oil performs several functions: keeping the engine clean, preventing rust and corrosion, acting as a coolant and reducing friction and wear. The oil cooler transfers heat from the oil to the engine jacket water. Oil temperature that is higher than normal indicates a problem with the lubrication system and/or the cooling system. Excessive oil temperature can adversely affect the cylinder heads, cylinder liners, pistons, and crankshaft bearings.
Exhaust temperature - This gauge indicates the exhaust temperature at the exhaust inlets to the turbochargers. The two exhaust temperatures may vary slightly. This may be due to variation of the sensitivity of the two thermocouples.The exhaust temperatures at the exhaust inlets to the turbochargers provide a good indication of engine performance. For engines with dry exhaust manifolds, the temperatures are representative of the actual temperatures of the valves. Monitor this parameter frequently.Normal operating temperatures and extreme operating temperatures for different ratings are listed in Table 1. If the recommendations for the engine installation, the rating, and engine maintenance are followed, most engines will operate at the normal limit or below the normal limit.
Severe damage to the engine can result if the exhaust temperature at the inlet to the turbocharger exceeds the extreme limit.
Table 1
Temperature Limits for the Exhaust Inlet to the Turbocharger
Rating (1) Normal Limit Extreme Limit
Continuous 650 °C (1202 °F) 692 °C (1278 °F)
Prime 677 °C (1250 °F) 718 °C (1325 °F)
Standby 704 °C (1300 °F) 746 °C (1375 °F)
(1) For the rating definitions, see this Operation and Maintenance Manual, "Engine Rating Definitions" (Reference Information Section).
Fuel pressure - This gauge indicates fuel pressure to the fuel injection pump from the fuel filter. A decrease in fuel pressure usually indicates a dirty fuel filter or a plugged fuel filter. As the fuel filter becomes plugged, there will be a noticeable reduction in the engine's performance.
Jacket water temperature - This gauge indicates the temperature of the engine coolant at the outlet for the jacket water. The temperature may vary according to the load. Do not allow the temperature to exceed the boiling temperature of the pressurized cooling system.The sensor for jacket water temperature must be fully submerged in order to detect the temperature correctly. If the engine is operating above the normal temperature range, perform the following procedure:
Reduce the load and/or the engine rpm.
Inspect the cooling system for leaks.
Determine if the engine must be shut down immediately or if the engine can be cooled by reducing the load and/or rpm.
System voltage - This gauge indicates the vo