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