Low Oil Pressure Switch. The low oil pressure switch (Figure 2) indicates when the oil pressure is
below 20 pounds per square inch (psi). The magneto circuit grounds the magneto, thus removing
ignition power from the engine. The engine is started by depressing the low oil pressure switch while
holding the start-magneto switch in the START position. The low oil pressure switch must be held
depressed until the oil pressure gage indication exceeds 20 psi or the engine will stop. When the oil
pressure is at 20 psi and above, the oil pressure holds the low oil pressure switch circuit open to prevent
grounding of the ignition.
Generator Warning Light. The generator warning light (Figure 2) indicates that the engine alternator is
generating an alternating current. This does not mean that this current is charging the battery.
Vacuum Gage. The vacuum gage (Figure 2) indicates the pump intake vacuum in inches of mercury (0-
Pressure Gage. The pressure gage (Figure 2) indicates the pump discharge pressure in psi (0-300).
Tachometer-Hourmeter. The tachometer (Figure 2) indicates the engine speed in RPM. The hourmeter
indicates the total elapsed running time of the pump.
Oil Pressure Gage. The oil pressure gage (Figure 2) indicates engine oil pressure in psi. The engine will
not operate if the oil pressure is below 20 psi. An oil pressure sender and a low oil pressure switch on
the engine furnish the power to operate the oil pressure gage.
Heater Receptacle and Switch. The switch opens or closes the circuit between the generator and the
voltage regulator. It supplies precise power to operate the M2 water heater.
Fuel quantity Gage. The fuel quantity gage (Figure 2) registers the amount of fuel in the fuel tank when
the fuel indicator switch is pressed.
Fuel Indicator Switch. The fuel indicator switch (Figure 2) is pressed and held to register the amount of
fuel that is in the fuel tank. The amount of fuel registers on the fuel quantity gages.
The pump and associated plumbing and gages are included in the pump unit assembly. The pump
(Figure 2) and associated items consist of a pump, a four-groove drive pulley, suction vacuum gage and
tubing, discharge pressure gage and tubing, prime/eductor piping, a discharge pressure pipe, and a drain
pipe. The pump consists of a tank (not to be confused with the tank unit assembly), tank cover,
lubrication fitting, breather, and other hardware. The pump drives liquids out through the discharge
piping according to valve settings.