Shibaura ST460, Operator'S Manual

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SECTION 3 – LUBRICATION AND MAINTENANCE
3-19
Thermostat
The thermostat ① , is a heat-sensitive valve
located in the coolant outlet connection in the
front of the cylinder head.
When the engine is cold, the thermostat shuts off
the flow of coolant to the radiator, allowing for
rapid engine warm-up. A recirculating bypass
allows coolant to circulate inside the engine
whenever the thermostat shuts off flow to the
radiator.
IMPORTANT: Do not attempt to improve cooling
by removing the thermostat. This will cause the
engine to run below normal working
temperatures, resulting in excessive engine
wear.
To install a new thermostat
①
, position it in the
recess of the water outlet connection so that the
heat element (spring end) is in the cylinder head
of the engine.
Fan Belt
NOTE: Check the condition of the fan beIt after
every 50 hours of operation. Check fan belt
tension after every 200 hours of operation.
A belt-driven fan located at the front of the
engine draws air through the fins of the radiator
to lower the temperature of the radiator coolant.
When 5 kg of thumb pressure is applied to the
belt midway between the belt pulleys, a correctly
tightened belt will deflect 5 - 10 mm.
If the fan belt is slipping, fan efficiency is lowered,
resulting in the engine running too hot. If the belt
is too tight, the life of the alternator bearing will
be shortened. If the fan belt shows signs of
cracking or fraying, install a new belt.
To adjust fan belt tension:
WARNING
Never attempt to loosen or tighten mounting
bolts while the engine is running.
1. Loosen the alternator mounting bolts
①
.
2. Pry the alternator away from the engine and
tighten the mounting bolts.
3. Recheck belt deflection.