© Feb. 2023
90 TB20J Plus Maintenance Manual
POWER SYSTEM
Fig 50 93 dust filter
NOTICE
• When turning off the machine for inspection, the
dust can be removed in time through the dust ex-
haust valve which should be replaced in time if it is
damaged or lost.
• Never operate the engine without equipped an air
filter, or dust and impurities entering the engine
may cause premature engine wear.
1. Loosen all the clips connecting the back cover to
the housing, then remove the back cover and clean
all dust from the back cover.
2. Turn the yellow sealing cap counterclockwise and
remove it, and then the outer filter element will be
visible.
3. Grasp the back cover lug of the outer filter element
with hand and pull the outer filter element out from
the cavity inside the air filter housing.
4. Maintain the outer filter element according to the air
filter maintenance instructions.
5. Before reinstalling the outer filter element, clean the
dust in the cavity of the filter and its thread with a
brush or cloth to ensure that the thread is smooth
and prevent dust from entering the inside of the out-
er filter element.
6. Reinstall all parts in reverse order correctly to en-
sure the filter is sealed and that no parts are
missed.
Belt Drive
• Do not carry out work on the belt drive unless
the engine is at standstill.
• After repairs: Check that all protective devices
have been installed and that all tools have
been removed from the engine.
Inspect the Belt
The belt should be replaced/reinstalled immediately if
the belt has:
• Cracked or broken
• Worn or unaligned
• Come off
• Glazed or hardened
If the belt is not properly tensioned, it should be
adjusted:
1. If a belt tension tester is available: Use the belt ten-
sion tester to measure the belt pretension and run-
ning tension. For correct belt pretension and
running tension, please refer to the chart of engine
belt tension.
2. If a belt tension tester is unavailable: Press down or
pull up the belt by hand in the middle of two pulleys
with the force of 10kg (22lb), and take the belt span
length as 200mm (7.9in) for calculation. Estimate
the tension by referring to the chart of engine belt
tension reference value, and refer to the chart of en-
gine belt tension for the correct running tension.
Note: If the belt span length is not equal to 200mm
(7.9in), estimate the tension reference value by pro-
portional increase or decrease.
Fig 51
Replace the V-ribbed Belt
It is recommended to replace the V-ribbed belt every 2
years or after 2000 hours of operation.
Clean the Engine
1. After warming up the engine, drain the engine oil,
clean the oil filter, and add anti-rust oil. Drain the
fuel and add anti-rust oil again.
2. Drain the coolant and add coolant containing rust
inhibitor.
3. Start the engine and idle it for 15-25min.
4. Fill with clean oil, fuel and coolant.
5. Take care to protect other parts.
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