
04-3
SECTION 04 - PROPULSION SYSTEM
1. Oil reservoirs
2. Impeller shaft end play
3. Venturi
4. Stator vanes
5. Impeller
NOTE:
Watercraft models equipped from the fac-
tory with the new composite jet pump housing
can not legally used the aluminum type housing
from previous models for IJSBA competition
events.
Impeller
The impeller is enclosed in the housing and it cre-
ates a dynamic force. The thrust created by the
impeller alone is minor, but it has a high power
absorption. The stator vane and venturi are essen-
tial to create thrust and to straighten out twisted
water coming of spinning impeller.
Stator
The function of the stator is to transform the dy-
namic force created by the impeller into forward
thrust.
The design principle is similar to the impeller al-
though the stator vanes are in a fixed position.
Venturi
The venturi function is to increase the fluid veloc-
ity using static pressure to generate the thrust.
Without the venturi, there would be very little
thrust. The venturi outlet diameter can be adjust-
ed to compliment the engine tuning and impeller
you have selected. Generally speaking, a slightly
larger (1-2 mm) outlet will improve acceleration
and should give better performance for closed
course competition.
Nozzle
The handlebar pivots the jet pump nozzle which
controls the watercraft direction.
These 2 items, the handlebar and nozzle, must be
adjusted properly to obtain optimum control of
the watercraft.
The steering system alignment is most important
to ensure the adequate control of the watercraft.
For alignment procedures, refer to appropriate
model year
Shop Manual.
VENTILATION (AIR LEAK)
Ventilation is caused by air being sucked through
jet pump which will reduce performance of the
pump. Pump ventilation reduces acceleration and
will be most noticeable during initial and low
speed accelerations. Engine RPM will increase
tremendously with very little increase in water-
craft speed. This condition feels much the same
as a slipping clutch in a car or motorcycle.
Jet pump ventilation is commonly traced to a poor
seal between ride shoe and hull.
To determine if jet pump is ventilating, first verify
the following:
– Verify if the watercraft accelerates quickly
when depressing throttle lever.
– Verify if the engine has a consistent top RPM.
– Verify impeller, impeller wear ring and pump
housing for wear and/or damage, or if debris is
caught in the grate or around drive shaft.
F01J4PA
1
2
3
4
5
;
WARNING
Ensure handlebar and jet pump nozzle oper-
ate freely from side to side and that jet pump
nozzle does not contact the side of venturi
housing.
;
WARNING
Always remove the safety lanyard from wa-
tercraft prior cleaning the propulsion sys-
tem, to avoid any accidental engine starting.
Содержание Bombardier
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