DETROIT DIESEL
Engine Systems
A new seal may be installed in the pump used on the
CAUTION: If the impeller is reuseable. exercise
care to prevent damage to the splined surfaces.
In-Line engine by placing the rubber seal ring in its
groove, starting the seal (with the lip facing the
4. Remove the cam retaining screw and withdraw the
impeller cavity) over the shaft and tapping it into
cam and wear plate assembly.
place against the seal spacer.
5. Remove the seal assembly from the pump used on a
9. Install the cam and wear plate assembly.
V-type engine by inserting two wires with hooked ends
NOTE: The wear plate is round and is doweled
between the pump housing and seal with the hooks
over the edge of the carbon seal. Remove the seal seat
to the cam. The wear plate must be installed
and gasket in the same way.
with the cam in the pump housing 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 screw and the hole in the pump body to
and placing metal screws in the holes so that they may
prevent any leakage. Then hold the cam with the
be grasped and pulled with pliers. Then remove the
rubber seal ring.
tapped hole 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
12. Install the neoprene splined seal(s) in the bore of
plate if it is worn excessively and remove any burrs.
the impeller.
Replace the seal, if necessary.
13. Turn the impeller several revolutions in the normal
8. Install the seal assembly in the pump used on a
direction of rotation to position the blades.
V-type engine as follows:
14. Affix a new gasket and install the pump cover.
a. If the seal seat and gasket were removed, place the
gasket and seal seat over the shaft and press them
The Jabsco raw water pump is equipped with a
into position in the seal cavity.
synthetic rubber impeller. Since synthetic rubber loses
its elasticity at low temperatures, impellers made of
b. Place the seal ring securely in the ferrule, and with
natural rubber should be installed when it is necessary
the carbon seal and washer correctly positioned
to pump raw water that has a temperature below 40 F
against the ferrule, slide the ferrule over the shaft
(4C).
and against the seal seat. Use care to ensure that
the seal ring is contained within the ferrule so
The natural rubber impeller can be identified by a
that it grips the shaft.
stripe of green paint between two of the impeller
c. Install the flat washer and then the marcel washer.
blades.
Page 30
