Yanmar 4LHA-HTP Operation Manual page 525

Chapter 6 Cooling Water System
3. Fresh Water Pump
Tap for water temperature switch
Inlet for water heater
From heat
exchanger
(fresh water tank)
3-2 Specifications of fresh water pump
Crank shaft speed (max.)
Pulley ratio
(crank shaft/pump shaft)
Pump shaft speed
Delivery capacity
Total head
3-3 Fresh water pump disassembly
(1) Do not disassemble the fresh water pump. It is difficult
to disassemble and, once disassembled, even more dif-
ficult to reassemble. Replace the pump as an assembly
in the event of trouble.
(2) When removing the fresh water pipe as an assembly
from the cylinder and cylinder head, replace the
cylinder intake pipe O-ring.
(3) When the fresh water pump body and cylinder intake
flange and/or fresh water pump and pump plate are
disassembled, retighten to the specified torque.
Tightening torque for
pump setting bolts
3-4 Fresh water pump inspection
(1) Bearing unit inspection
Rotate the impeller smoothly. If the rotation is not
smooth or abnormal noise is heard due to excessive
bearing play or contact with other parts, replace the
pump as an assembly.
(2) Impeller inspection
Check the impeller blade, and replace if damaged or
corroded, or if the impeller blade is worn due to contact
with pump body.
To heat exchanger
m
(fresh water tank)
Tap for water temperature
sender unit
3600 rpm
0134/0120
«134/0120= 1.083
2970-3030 rpm
150 //min (5284 in.Vmin)
5m (16.4 ft)
6 8 6 - 1 0 7 9 ( 7 0 - 1 1 0 ) N(kgf)-cni
Outlet for water heater
Thermostat
Beanng unit
V pulley \
V pulley flange
Pump body
Mechanical seal
(3) Check the holes in the cooling water and bypass lines,
clean out any dirt or other foreign matter and repair as
necessary.
(4) Replace the pump as an assembly if there is excessive
water leakage due to mechanical seal or impeller seal
wear or damage.
(5) Inspect the fresh water pump body and flange, clean
off scale and rust, and replace if corroded.
(6) Measure the clearance between the impeller and the
pump body, and the impeller and the plate.
Measure the clearance between the impeller and the
pump body by pushing the impeller all the way towards
the body, and inserting a thickness gauge diagonally
between the impeller and the body.
Measure the clearance between the impeller and the
plate (pump body bracket) by placing a straight-edge
against the end of the pump body and inserting a
thickness gauge between the impeller and the straight-
edge.
6-8
4LHA Series
Cyli. head
Pump plate
—- To cylinder body
O ring
P i p e flange
Gasket'
v