INSTRUMENTSEngine monitoring instruments provide the operator with important information concerning the operating condition of theengine. Generally, the instruments are not as precise as test instruments but they will provide sufficiently accurateindications of the operating condition of the engine.ENGINE OIL PRESSURE GAUGEThis is one of the most important instruments and should be checked as soon as the engine starts. Normal oil pressure is30/60 P.S.I. (2.1/4.2 kgf/cm 2) at maximum engine speed with the engine at normal operating temperature. During thelife of the engine, as bearing surfaces wear, there will be a gradual decrease in pressure, There will also be a slightdecrease in pressure when the oil is hot or if the wrong grade of oil is used during certain climatic conditions. Refer topage 58 for the correct oil grades.Fig. 4 Typical Instrument PanelTACHOMETERThis instrument provides the operator with the speed, in revolutions per minute (rpm), of the engine crankshaft. The valueindicated on the dial usually has to be multiplied by one hundred (100) to arrive at the engine rpm. (e.g., 20 x 100 = 2,000rpm).NOTE: Initial calibration may be required for certain tachometers.WATER TEMPERATURE GAUGEThis instrument provides the operator with the temperature of the engine coolant. The coolant temperature (normal)should remain within the ranges listed on page 54. If a higher than normal temperature is experienced, investigate andcorrect immediately (refer to page 54).AMMETERThis instrument provides the operator with an indication of whether or not the battery is being charged by the alternator.An indication that the battery is discharging should be investigated and corrected immediately.-30-
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