826135 Mercury NUT, (1.00-14) (BLACK)

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.For G3400 Engines, the typical oil pressure at rated rpm is 275 to 600 kPa (40 to 87 psi).For G3400 Engines at low idle, the typical oil pressure is 186 to 344 kPa (27 to 50 psi).If no engine oil pressure is indicated, then stop the engine.
Oil Filter Differential Pressure - 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, the pressure will increase. Replace the engine oil filter elements when the oil filter differential pressure reaches 103 kPa (15 psi).
Jacket Water Coolant 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. The temperature should never be allowed to exceed the boiling temperature of the pressurized cooling system. The operating range is 88 to 98 °C (190 to 205 °F). Higher temperatures may occur under certain conditions.The engine should operate within the normal temperature range. The sensor for jacket water coolant 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.
Inlet Manifold Air Temperature - This gauge indicates the inlet manifold air temperature to the cylinders.
High inlet manifold air temperature increases the risk of detonation. Detonation can cause damage to the engine. Ensure that the aftercooling system is operating properly.
The inlet manifold air temperature depends on the engine's aspiration and the water temperature regulator for the separate circuit aftercooler (if equipped). If the maximum temperature is exceeded, the engine will be unable to provide rated power. Derating occurs at temperatures that are greater than the maximum. See Table 1 for maximum temperatures of different engines.
Table 1
Maximum Inlet Manifold Air Temperatures for G3400 Engines
Aspiration Water Temperature Regulator Maximum Inlet Manifold Air Temperature
Naturally aspirated n/a 25 °C (77 °F) (1)
Separate Circuit Aftercooling 32 °C (90 °F) (2) 43 °C (110 °F)
Separate Circuit Aftercooling 54 °C (130 °F) (2) 65 °C (150 °F)
(1) This temperature is for an engine at an altitude of 152 m (500 ft) above sea level. A greater temperature or a higher altitude requires derating.
(2) Water inlet to the aftercooler
Inlet Manifold Air Pressure (TA Engines) and Inlet Manifold Vacuum (NA Engines) - For TA engines, this gauge indicates the air pressure (turbocharger boost pressure) in the air plenum (air inlet manifold) after the aftercooler. For NA engines, this gauge is the pressure of the inlet manifold vacuum. For all engines, this pressure is relative to the load. This pressure may be used for estimating power output. Several factors affect the inlet manifold air pressure. All of these factors must be accounted for when power is estimated from inlet manifold air pressure: air restriction, exhaust restriction, coolant temperature, ambient air temperature, variation of the fuel, air/fuel ratio, ignition timing and condition of the valves.For more information, see the performance curves in the Engine Performance manual. The manual is available from your Caterpillar dealer.
Tachometer - This gauge indicates the engine rpm.
An overspeed can result in serious damage to the engine. To help prevent engine damage, never allow the engine to exceed the rated rpm.
Note: The rated rpm is stamped on the engine Information Plate.
Service Hour Meter - This meter indica