Yanmar 3YM20, Руководство по обслуживанию

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2. Inspection and adjustment
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4) Nozzle punch mark
(3) Check the impeller of the cooling water pump (seawater pump)
The impeller must be replaced with new one periodically (every 1000 hrs or four years whichever comes
first).
Refer to 2.2.5 (5) for the procedure.
(4) Clean & check the water passages
When it is used for a long time, cleaning of the cooling water passages is periodically necessary,
because trash, scales, rust, and so on collect in the cooling water passages and the cooling
performance declines.
(a) Cleaning and inspection of cooling water rubber hoses.
1) Remove the cooling water rubber hoses for the fresh water line and the seawater line.
2) Check the dust and trash inside the hoses. If necessary, clean it.
3) Check the crack and the deterioration of the rubber hoses. If necessary, replace with new ones.
4) Replace the used hose clips with new ones, if necessary.
(b) Heat exchanger inspection
1) Cooler core inspection
a) Inspect the inside of the tubes for rust or scale buildup from seawater, and clean with a wire brush
if necessary.
NOTE: Disassemble and wash when the cooling water temperature reaches 85
°
C.
b) Check the joints at both ends of the tubes for looseness or damage, and repair if loose, Replace if
damaged or corroded
c) Check tubes and replace if leaking.
d) Clean any scale or rust off the outside of the tubes.
2) Heat exchanger body water leakage test
a) Check heat exchanger body and side cover for dirt and corrosion. Replace, if excessively
corroded, or cracked.
b) Inspect seawater and fresh water inlets and outlets, retighten any joints as necessary and clean
the insides of the pipes.
c) Check the exhaust gas intake flange and line, and replace if corroded or cracked.
NP - DN O P D N159
Design code
BOSCH
Type: pintle type
Injection angle
Size: size P
Throttle type
Identification
number
NP-DNOPDN159