Onan MJA Series Service Manual page 24

22
COOLING SYSTEM
INSTALL THIS SEAL WITH LI P
"TOWARD IMPELLER ­
INSTALL THIS SEAL WITH LIP
AWAY FROM lMPELLER-
FIG 3.1. D - RUBBER· IMPELLER WATER PU:MP.
4. Loosen the set screw on the side of the pump 3 or 4 turns and tap
it lightly to free the cam from the pump body. Lift out the cam
and wear plate.
5. Drive tbe'2 watersealsout from the drive end of the pump. NOTE:
Remove these only if they are to be replaced.
B.
Repair. -
Most water pump ::failure is cau-sed by the rubber impel­
~;,
ler. If the impeller fails, check for pock marks on its end surfaces.
These are a sign of
air in
the cooling system (Sect 3.1. 2) which re­
duces pump lubrication and causes overheating.
If
the cam, wearplate, or end cover show excessive wear, -replacethem.
If
the pump leaks water along its. shaft, replace the water seals.
C. Assembly. - Before beginning assembly, clean aU old permateX
from the- inside surfaces of the pump body and from the cam and wear
plate.
1. Install both seals in the body with lips pointing in opposite directions.
2. Drop the wear plate in the body with tanged side out.
3. Permatex top surface and back face of cam and install with cam
screw. Permatex the screw threads and line up the hole in the cam
with the tang on the wea:r plate.
4. Install the shaft and impeller assembly.
5. Install the gasket and end cover with screws.
3.1.4 HEAT EXCHANGER COOLING (Optional)
ONAN Heat Exchanger cooling is available either factory installedoI' as
a kit for customer installation.
A
completed heat exchanger install:3,tiQIJ
contains 2 water systems, the closed water system and raw water sys ­
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