Fuel Pump Test; Thermostat Test - Toro Groundsmaster 300 Series Service Manual

Fuel Pump Test (Fig. 22)
1. Turn the ignition switch to the ON position. Test for
pump operation by listening for the pump oscillating
sound, or by feeling for vibration which indicates the
pump is operating.
2. If no pumping action occurs when the ignition switch
is turned on, connect a 12 volt DC battery directly to the
pump (Fig. 22). If the pump now operates, check for an
electrical failure of the pump circuit, eg. fuses, connec-
tions, wires, etc.
3. The delivery of the fuel pump may be checked by
disconnecting the fuel lines from the water separator
and fuel filter and routing them to a can of filtered diesel
fuel and a drain pan (Fig. 22). Activate the pump and
measure the amount of fuel pumped in during a 15
second time interval. The standard pump rate is approxi-
mately 8 ounces (225 cc) in 15 seconds.
4. If the fuel delivery rate is below the standard value
the pump should be disassembled and checked. (See
Fuel Pump Service in the Fuel System Repairs section
of this chapter.)
Thermostat Test (Fig. 23)
If the engine overheats and a faulty thermostat is sus-
pected, the thermostat should be tested.
1. Remove the thermostat (see Thermostat Removal
and Installation in the External Engine Component Re-
pair section of this chapter).
2. Put the thermostat in a container of water with a
thermometer and heat the water (Fig. 23).
Valve cracking temperature: 76.5
Full-open temperature: 90
Valve lift: 8 mm (0.314 in.)
3. If the thermostat fails to open, only partially opens, or
sticks, it should be replaced.
Testing
o o
C (177 F).
o o
C (194 F)
Page 4 - 24
Figure 22
Figure 23
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Groundsmaster 300 Series