Toro Greensmaster 3420 TriFlex, Service Manual

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Greensmaster 3320/3420 Page 6 -- 69 Electrical System
Temperature Sender (Greensmaster 3420)
The temperature sender is located near the alternator
on the water flange attached to the engine cylinder head
(Fig. 88).
The resistance of the temperature sender reduces as
the engine coolant temperature increases. The chang-
ing resistance of the temperature sender signals the
console temperature gauge to indicate engine coolant
temperature during machine operation.
Temperature Sender Test
1. Park machine on a level surface, lower cutting units,
stop engine, apply parking brake and remove key from
ignition switch.
2. Locate temperature sender on engine and discon-
nect wire harness connector from sender.
CAUTION
Make sure engine is cool before removing the
temperature sender from engine.
3. Lower coolant level in the engine and remove the
temperature sender from water flange.
4. Put sender in a container of oil with a thermometer
and slowly heat the oil (Fig. 89).
CAUTION
Handle the hot oil with extreme care to prevent
personal injury or fire.
NOTE: Prior to taking resistance readings with a digital
multi meter, short the meter test leads together. The me-
ter will display a small resistance value (usually 0.5
ohms or less) due to the internal resistance of the meter
and test leads. Subtract this value from from the mea-
sured value of the component you are testing.
5. Check resistance of the sender with a multimeter
(ohms setting) as the oil temperature increases.
A. The meter should indicate from 11.4 to 13.6 ohms
at 68
o
F (20
o
C).
B. The meter should indicate from 2.3 to 2.6 ohms at
140
o
F (60
o
C).
C. The meter should indicate from 0.6 to 0.7 ohms at
212
o
F (100
o
C).
6. Replace temperature sender if specifications are not
met.
7. Install temperature sender to the water flange.
A. Clean threads of water flange and temperature
sender thoroughly. Apply thread sealant to the
threads of the sender.
B. Screw sender into the water flange until it is finger
tight. Then, tighten sender an additional 2 to 3 full
turns.
C. Connect wire harness connector to sender.
8. Fill engine cooling system.
Figure 88
1. Temperature sender 2. Alternator
2
1
Figure 89
Elec
trica
l
System