52
OM-C3 11/21
Service and Maintenance - 2000 Hour
SP 27. Inspect and Repair Sea Water Pump
(M150C13)
• Inspect pump housing for seal leakage
1. Inspect the sea water pump housing weep hole, if
equipped, for evidence of water or oil indicating seal
leakage. If water leakage is evident, replace impelle
and front housing/shaft seal.
If oil leakage is evident, consult an authorized Northern
Lights dealer for repair.
Remove and Inspect Impeller
1. Close sea cocks and drain sea water system.
2. Remove cover plate (A) from sea water pump.
NOTE: Special impeller puller tool is provided with
sea water pump rebuild kits. If tool is not available, the
impeller can normally be removed by using two pair of
pliers to grip impeller vanes on opposite sides of impeller.
Rotating the pump shaft by hand may help free the
impeller.
Petroleum based lubricants can cause the impeller to
swell, and are not recommended to free a stuck impeller.
3. Remove impeller (B) and shaft key (C) (if equipped)
from pump housing.
4. Remove O-ring (D).
5. Inspect cam plate (E) for evidence of heavy pitting or
wear. Replace as needed.
6. Inspect impeller for damages such as tears, stress
cracks, excess abrasions on vane ends, or chunks of
material missing. Impellers that are run dry will over
heat and fail the impeller blades at the root. Impellers
that swell and stick, fail the impeller in the middle of
the blade. If impeller replacement is necessary, order
an impeller repair kit.
IMPORTANT: If impeller has chunks of material missing,
the heat exchanger, aftercooler, marine gear oil cooler and
any other circuit that are cooled by raw water should be
thoroughly cleaned and flushed.
7. Install shaft key (C) (if equipped) on shaft.
8. Lubricate new impeller blades with a non-petroleum
based lubricant such as silicone or soapy water. Install
impeller using a twisting motion and be sure the
impeller blades are bent in the same direction as they
were upon removal to prevent damage at startup.
Rotate impeller on shaft to align keyways/splines and
slide the impeller onto the shaft.
Remove cover
plate (A)
9. Using a new O-ring (D), install cover plate and tighten
cap screws with washers securely.
10. Install sea water pump and tighten cap screws to 73
N·m (54 lb-ft).
11. Connect sea water inlet and outlet tubes.
Tighten mounting cap screws evenly until secure.
12. Replace O-rings on oil tubes and install oil filter
housing and oil tubes. Tighten mounting cap screws to
35 N·m (26 lb-ft).
13. Open sea cocks, start engine and check pump
operation.
Remove and inspect components. Impeller (B), Shaft key (C),
O-ring (D), Cam plate (E)
Inspect sea
water pump
impeller
