Engine Systems
DETROIT DIESEL
CAUTION: If the impeller is reusable,
A new seal may be installed in the pump used on the In-
exercise care to prevent damage to the
Line engine by placing the rubber seal ring in its groove,
splined surfaces.
starting the seal (with the lip facing the impeller cavity)
over the shaft and tapping it into place against the seal
4. Remove the cam retaining screw and withdraw the
spacer.
cam and wear plate assembly.
9. Install the cam and wear plate assembly.
5. Remove the seal assembly from the pump used on a
V-type engine by inserting two wires with hooked ends
NOTE: The wear plate is round and is
between the pump housing and seal with the hooks over
doweled to the cam. The wear plate must be
the edge of the carbon seal. Remove the seal seat and
installed with the cam in the pump housing
gasket in the same way.
as an assembly.
6. The seal may be removed from the pump used on
the In-line engine by drilling two holes in the seal case
10. Apply a non-hardening sealant to the cam retaining
and placing metal screws in the holes so that they may
screw-and the hole in the pump body to prevent any
be grasped and pulled with pliers. Then remove the
leakage. Then hold the cam with the tapped hole
rubber seal ring.
aligned and secure it with the screw.
7. Clean and inspect the impeller, cam and wear plate
11. Compress the impeller blades to clear the off-set
assembly and water seal. The impeller must have a
cam and press the impeller on the splined shaft. The
good bond between the neoprene and the metal. If the
blades must be correctly positioned to follow the
impeller blades are damaged, worn or have taken a
direction of rotation.
permanent set, replace the impeller. Reverse the wear
plate if it is worn excessively and remove any burrs.
12. Install the neoprene splined seal(s) in the bore of
Replace the seal, if necessary.
the impeller.
8. Install the seal assembly in the pump used on a V-
13. Turn the impeller several revolutions in the normal
type engine as follows:
direction of rotation to position the blades.
a. If the seal seat and gasket were removed, place the
14. Affix a new gasket and install the pump cover.
gasket and seal seat over the shaft and press them into
position in the seal cavity.
The Jabsco raw water pump is equipped with a synthetic
rubber impeller.
Since synthetic rubber loses its
b. Place the seal ring securely in the ferrule, and with
elasticity at low temperatures, impeller made of natural
the carbon seal and washer correctly positioned against
rubber should be installed when it is necessary to pump
the ferrule, slide the ferrule over the shaft and against
raw water that has a temperature below 40F.
the seal seat. Use care to ensure that the seal ring is
contained within the ferrule so that it grips the shaft.
The natural rubber impeller can be identified by a stripe
of green paint between two of the impeller blades
c. Install the flat washer and then the marcel washer.
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