6.
Grasp frame spacer under fuel tank and
slide engine/sled assembly back from
pump adapter. Slide far enough to
access impeller approximately 10" to
12".
7.
Tighten 1/2-13 nuts to prevent
engine/sled from moving during
maintenance procedure.
MECHANICAL SEAL REPLACEMENT
NOTE: Always replace the seal assembly (Ref.
No. 7) and shaft sleeve (Ref. No. 8) to ensure
proper mating of mechanical components.
NOTE: Always inspect impeller stub shaft ball
bearing (Ref. No. 15) during seal replacement.
The bearing may have been damaged by
leaking water. Refer to IMPELLER STUB
SHAFT BEARING REPLACEMENT section.
1. Access impeller/seal plate area as
described in SLIDING ENGINE SLED
OPERATION section.
2. Unscrew impeller (Ref. No. 5) from the
impeller stub shaft (Ref. No. 16). Turn
the impeller counterclockwise. Use a
rubber mallet or soft block of wood and
hammer to loosen impeller. Remove any
impeller shims (Ref. No. 6), shaft sleeve
and seal head from impeller stub shaft.
3. Remove two 1/2-13x1" cap screws (Ref.
No. 12) holding seal plate (Ref. No. 10)
to bearing housing adapter (Ref. No.
11). Remove seal plate from bearing
housing adapter.
4. Remove impeller shaft washer (Ref. No.
14) and inspect impeller stub shaft ball
bearing for water damage or wear.
Replace shaft washer with flat surface
toward impeller.
5. Push seal seat from the seat plate
recess with a screwdriver.
6. Clean the seal plate recess before
inserting a new seal seat.
7. Carefully wipe the polished surface of
the seal seat with a clean cloth.
8. Wet the rubber portion of he seal seat
with a light coating of soapy water.
9. Press the new seal seat squarely into
the cavity in the seal plate. If the seal
seat does not press squarely into the
cavity, it can be adjusted in place by
pushing on it with a piece of pipe.
Always use a piece of cardboard
between the pipe and the seal seat to
avoid scratching the seal seat. (This is a
lapped surface and must be handled
very carefully).
10. After the seal seat is in place, ensure
that it is clean and has not been
scratched or cracked.
11. Using a clean coth, wipe the impeller
stub shaft and make certain that it is
clean.
12. Install seal plate and secure to bearing
housing adapter face with two 1/2-13x1
cap screws.
13. Apply a light coating of soapy water to
the inside rubber portion of seal head
and slide onto the shaft sleeve. Slip the
shaft sleeve and seal head onto the
impeller stub shaft with seal head lapped
surface towards seal seat lapped
surface.
14. Replace any impeller shims removed
during disassembly.
15. Screw the impeller back in place
tightening until it is seated against shims
and shaft sleeve.
NOTE: Make sure seal spring retainer is not
pinched between impeller/shims and end of
shaft sleeve.
16. Refer to section entitled Shim
Adjustment at this time if shaft sleeve or
any other parts listed therein have been
replaced.
17. Check O-ring (Ref. 9), make sure it is
not damaged or worn and is in position
on seal plate.
NOTE: Always inspect O-ring seals. Replace
when cracked or worn. Wet O-ring with soapy
water for ease of assembly.
18. Slide engine/sled back into position
aligning lead diameter on seal plate with
adapter inside diameter. Replace three
1/2-13x1-3/4 cap screws. Tighten six
1/2-13 hex nuts clamping side rails to
frame rails.
19. Remount any other parts and reconnect
spark plug wires and battery.
SHIM ADJUSTMENT
Manual method:
1. When installing a replacement impeller
(Ref. No. 5), shaft sleeve (Ref. No. 8),
bearing housing adapter (Ref. No. 11),
seal plate (Ref. No. 10), or volute (Ref.
No. 41), it may be necessary to vary the
number of impeller shims (Ref. No. 6)
that will be required. This is easily done
by adding one shim more than was
removed and reassembling the pump as
described in Mechanical Seal
Replacement section.
2. Ensure that volute, adapter (Ref. No.
42), seal plate and bearing housing
adapter are fitted firmly. Check tightness
of all fasteners.
3. Remove spark plug wires and bump
engine over slightly with electric starter.
If engine does not turn freely or
interference between impeller and volute
can be heard, disassembly pump and
remove one shim.
NOTE: When adding or removing shims, it is
best to proceed with a 0.020" increment each
time. If engine does turn freely, add shims until
it does strike, then remove a 0.020" shim. This
will ensure maximum performance.
4. Proper running clearance is 0.020" to
0.040"
5. Follow the above procedure until proper
clearance is obtained.
Measurement method:
1. When installing a replacement impeller,
shaft sleeve, bearing adapter, seal plate
or volute, it may be necessary to vary
the number of impeller shims that will be
required. This can be accomplished by
measurement with a suitable size depth
micrometer or similar measuring
instrument.
2. Measure depth from pump adapter-seal
plate mounting surface to impeller face
of volute. Measurement should be close
to 5.960".
3. Add or remove impeller shims until
height of impeller face to seal plate-
pump adapter mounting surface
measures 0.020" to 0.040" shorter than
depth measured in previous step.
4. Slide engine/sled back into position
aligning lead diameter on seal plate with
adapter inside diameter. Replace three
1/2-13x1-3/4 cap screws. Tighten six
1/2-13 hex nuts clamping side rails to
frame rails.
5. Remove spark plug wires and bump
engine over slightly with electric starter.
If engine does not turn freely or
interference between impeller and volute
can be heard, disassemble pump and
remove one shim. Rotate engine again.
Engine must rotate freely.
IMPELLER AND VOLUTE REPLACEMENT
Impeller and volute are subject to wear only by
abrasive sand or sediment laden liquids. If
badly worn, all these parts can be replaced and
the pump thus restored to full efficiency.
NOTE: When the clearance between the
impeller and the volute. The increased
clearance can cause lengthened priming times
and reduce pumping capacity. If both the
priming and capacity of your unit are
satisfactory for your application, it is
recommended that no corrective maintenance
be performed regardless of what clearances on
you unit may have developed, since the
increased clearances in themselves are not
generally harmful to your pump. Normally, new
pump clearances can be restored by simply
shimming behind the impeller. If the impeller is
badly worn, it is recommended that the impeller
be replaced. This is usually all that is required
since only on unusually abrasive services does
the cast iron volute show deterioration.
Occasionally a stone or hard object might get
caught in the impeller and cause damage to the
volute/cutwater. In these cases, follow the
instructions below for replacement.
1. Refer to SLIDING ENGINE SLED
OPERATION section for procedure to
access the volute and inside of the
casing.
3