Yanmar 3TNV82A-B Service Manual page 239

EGR system
To remove deposited carbon, use carbon cleaner,
kerosene, or some other liquid capable of removing
carbon as well as a soft brush or cloth to clean the
valves, taking care not to damage their parts.
Upon completion of carbon removal, wipe off water
and liquid, make sure that the case, valve, and
stopper are free of foreign matter, and then reinstall
the valve and related parts.
Stopper chamfer
Exhaust gas
passage hole
17.5
Assemble without
misalignment.
20
Figure 6-159
Precautions for installation
1. The valve and stopper must be installed in their
specific orientations. As shown in the figure
above, install the valve and stopper so that they
are located on the left-hand side of the lead
valve.
2. Install the valve by tightening the machine
screw while ensuring that it is evenly positioned
inside the case window.
3. The machine screw must be tightened with
torque of 1.37±0.2N•m(14±2kgf•cm).
4. After tightening the machine screw, mark it with
a marker to indicate that it has already been
tightened.
TNV DI Service Manual
Valve plate
EGR cooler
The EGR cooler must be periodically cleaned every
1500 hours because the exhaust gas passage is
subject to carbon deposition and the cooling water
transit portion to scale deposition and these
depositions gradually deteriorate the cooling of
recirculated gas, thus resulting in higher gas
temperatures and lower effective circulation
amounts (EGR ratio).
To remove deposited carbon from the gas passage,
use compressed air (0.19MPa(2kg/cm2) or lower).
Then dip the gas passage in carbon cleaner,
kerosene, or some other liquid capable of removing
carbon; leave it dry and blow it with compressed air
again.
To clean the water transit portion, dip it in a solution
of descaling detergent diluted with water and wash
it.
EGR pipe and other connecting elbows
The exhaust gas passage is subject to carbon
deposition when used over time. To remove
deposited carbon from the gas passage, use
compressed air (0.19MPa(2kg/cm
exhaust gas passage is heavily fouled, clean it by
dipping it in carbon cleaner, kerosene, or some
other liquid capable of removing carbon.
ENGINE
2 ) or lower). If the
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