891728 Mercruiser STUD, Grounding

If no oil pressure is indicated, STOP the engine. If maximum coolant temperature is exceeded, STOP the engine. Engine damage can result.
Engine Coolant Temperature - This gauge indicates the engine coolant temperature. The temperature may vary according to the load. Do not allow the temperature to exceed the boiling temperature of the pressurized cooling system.Fully submerge the engine coolant temperature sensor to detect correctly the temperature. 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.
Engine Load - This gauge indicates a percentage of the full rated torque. The calculation of the percentage is based on these factors: flow of fuel, engine rpm, fuel energy content and fuel correction factor. This gauge flashes if the torque exceeds the maximum limit that is programmed into the control strategy.
Engine Oil Pressure - The oil pressure should be greatest 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 is stable. A lower oil pressure is normal at low idle. If the load is stable and the gauge reading changes, perform the following procedure:
Remove the load.
Reduce engine speed to low idle.
Check and maintain the oil level.
Engine Oil Temperature - This gauge indicates the engine oil temperature after the oil has passed through the oil cooler. The oil cooler is thermostatically controlled.
Exhaust Temperature - This gauge indicates the exhaust temperature at the exhaust inlets to the turbochargers. The two exhaust temperatures may vary slightly.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.
Severe damage to the engine can result if the exhaust temperature at the inlet to the turbocharger exceeds the extreme limit.
Fuel Level - This gauge indicates the fuel level in the fuel tank. Normally, the fuel level gauge will register the fuel level only when the switch is in the ON position.
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 performance.
Fuel Temperature - This gauge indicates the temperature of the fuel. A high fuel temperature can adversely affect performance. If the temperature of the fuel is too low, the fuel filter may begin to plug. See this Operation and Maintenance Manual, "Fuel and the Effect from Cold Weather" for more information.
Fuel Usage - This gauge indicates the rate of fuel usage.
Inlet Manifold Air Pressure - This gauge indicates the air pressure (turbocharger boost pressure) in the air inlet manifold after the aftercooler. The inlet manifold air pressure depends on the engine rating, the load, and the operating conditions. To establish the normal inlet manifold air pressure, compare the data from the gauge to the data from the engine commissioning and look for trends.
Inlet Manifold Air Temperature - This gauge indicates the inlet manifold air temperature after the aftercooler. As the inlet air increases in temperature the following conditions occur: expansion of the air, less oxygen in the cylinders and less power. If the temperature of the inlet air is too high during full speed and load operation, the engine may consume excessive fuel.
Service Hour Meter - This gauge indicates the total number of clock hours on the engine.