Onan MDKBH Series, Service Manual

Page: 36 / 90

4-11
6. Remove the 4 pump cover screws (Figure 4-9)
and remove the impeller and O-ring. Use two
pliers to grip vanes on opposite sides if the im-
peller is difficult to remove. It will be necessary
to check for and cleanout pieces of the impeller
from the heat exchanger and exhaust elbow if
vanes have broken off.
7. Install the new impeller. It helps to twist the im-
peller clockwise (the way it turns) while squeez-
ing it into the housing.
8. To provide initial lubrication and better pump
suction before water reaches the pump, wet the
inside of the pump and impeller with water,
soap solution or a silicone lubricant.
CAUTION
Do not lubricate the impeller
with grease or oil or other petroleum prod-
ucts because they are known to chemically
attack impeller materials.
9. Secure the cover and O-ring.
10. Remount the pump, reconnect the hoses, ad-
just V-belt tension (Page 4-9) and reassemble
the enclosure panels and doors.
11. Fill the sea water strainer for faster priming at
startup if it is above the water line.
12. Open the sea cock, reconnect the battery
cables (negative [ – ] last) and start the genset.
The genset will shut down within 8 seconds if
there is no raw water flow and Fault Code No. 7
(p. 11-6) will be declared. If it shuts down, find
out why, remove any blockage and restart the
genset.
IMPELLER
O-RING
COVER AND
SCREWS
FIGURE 4-9. REPLACING THE IMPELLER
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