INSTRUMENTS
Engine monitoring instruments provide the operator with important information concerning the operating condition of the
engine. Generally, the instruments are not as precise as test instruments but they will provide sufficiently accurate
indications of the operating condition of the engine.
ENGINE OIL PRESSURE GAUGE
This is one of the most important instruments and should be checked as soon as the engine starts. Normal oil pressure is
30/60 P.S.I. (2.1/4.2 kgf/cm 2) at maximum engine speed with the engine at normal operating temperature. During the
life of the engine, as bearing surfaces wear, there will be a gradual decrease in pressure, There will also be a slight
decrease in pressure when the oil is hot or if the wrong grade of oil is used during certain climatic conditions. Refer to
page 58 for the correct oil grades.
Fig. 4 Typical Instrument Panel
TACHOMETER
This instrument provides the operator with the speed, in revolutions per minute (rpm), of the engine crankshaft. The value
indicated on the dial usually has to be multiplied by one hundred (100) to arrive at the engine rpm. (e.g., 20 x 100 = 2,000
rpm).
NOTE: Initial calibration may be required for certain tachometers.
WATER TEMPERATURE GAUGE
This 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 and
correct immediately (refer to page 54).
AMMETER
This 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.
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