Hamilton Jet HJ241, Manual

Page: 129 / 202

9.25
9 OVERHAUL
9.7 T
AILPIPE
A
REA
- O
VERHAUL
HJ-241 / HSRX
BALANCING:
1. The Impeller must be balanced if welding or
grinding has been carried out on the Impeller.
2. Balance the Impeller statically, preferably on the
Mainshaft with the Coupling and all Impeller and
Coupling Keys in place. If this is not possible
then balance the impeller statically on a suitable
mandrel set on horizontal knife edges or bars to
within the maximum out of balance specified.
3. Balance to within 27 gm-cm (0.38 oz/ins.).
Balance weights of 316SS may be welded to the
inside of the hub and grinding is permitted.
PASSIVATION:
1. If the Impeller has been welded, passivation is
required.
2. Immerse the Impeller in hot 30% Nitric Acid for
at least 2 hours.
3. Rinse in clean water.
4. If nitric acid immersion is not possible, a "Brush
On" pickling / passivation gel may be used on
weld and heat affected areas.
9.7.7 Tailpipe Overhaul
Refer to Drawings HJ-241-01-000 Basic Jet Assem-
blies Standard and Dry Run Sht 1 & 2.
TAILPIPE:
1. Check the Marine Water Bearing [2] and Bearing
Sleeve [4] for wear or severe scoring and if
necessary replace.
Refer to Section 8.5.1 Jet Unit
Servicing Details Item No16 h). Also refer to Sec-
tion 9.7.1 Impeller - Checking for Wear. Replace
automatically if the Impeller has just been built
up and the Wear Ring has been replaced.
2. Use an internal extractor to pull the Marine
Water Bearing [2] from the Tailpipe.
3. Apply grease to the Tailpipe bore before inserting
a new Marine Water Bearing but ensure that
grease is kept away from the Rubber Bearing
surfaces.
4. When pressing in the new marine water bearing,
use a wooden block under the nose of the
Tailpipe to take the load.
NOZZLE BUSHES - REPLACEMENT:— Ensure that
all worn or damaged Steering and Reverse System
Bushes, Scrapers and Seals have been replaced prior
to re assembly of the Tailpipe and Nozzle.
Refer to
Section 9.4.2 Steering Shaft Removal and Section
9.4.4 Nozzle Assembly Overhaul.
EXTERNAL TAILPIPE ANODES [39] -
REPLACEMENT:—Refer to Drawings
HJ-241-01-
000 Basic Jet Assemblies Standard and Dry Run Sht 1
& 2
and Drawing HJ-241-13-002 Anode Locations .
1. Check the 2 x external Tailpipe Anodes [39]
attached to the underside of the Tailpipe, if these
are less than half of their original size, they
should be replaced.
a) To replace the External Tailpipe Anodes, carry
out the following operation:-
b) Remove the Nuts [27], Spring Washers [28]
and Screws [40] securing the Anodes to the
web on the underside of the Tailpipe.
c) Remove the External Anodes [39].
d) Clean up the contact area where the Anode
will locate to remove any corrosion and paint.
Repair the paint finish.
e) Fit a new External Anodes [39] and secure
with Screws [40], Spring Washers [28] and
Nuts [27]. Torque load to the recommended
torque.
2. If the Anodes are still in good condition, ensure
that they have not been painted over.
3. Scrub down the Anodes with a wire brush if a
coating has built up on the Anodes.
INTERNAL TAILPIPE ANODES [50] -
REPLACEMENT:—Drawings
HJ-241-01-000 Basic
Jet Assemblies Standard and Dry Run Sht 1 & 2 and
Drawing HJ-241-13-002 Anode Locations refer.
1. Check the 4 x Internal Tailpipe Anodes [50]
attached to the Anode Mounting Plate [44] which
is fitted to the forward face of the Tailpipe.
Should these be less than 2/3rds their original
size, they should be replaced.
2. To replace the 4 x Internal Tailpipe Anodes [50],
carry out the following operation:-
a) With the Tailpipe removed from the Intake
[19], remove the Nyloc Nuts [65] and Spring
Washers [28] from the Studs [52] attaching
the Anode Mounting Plate [44] to the Tailpipe.
W
ARNING
Appropriate safety glasses, pro-
tective gloves and clothing must
be worn to prevent skin exposure
to nitric acid.