Section 05
COOLING SYSTEM
Sub-Section 02
(CIRCUIT)
05-02-1
CIRCUIT
2
GENERAL
The cooling system is equipped with a fitting spig-
ot for flushing purposes (a hose adapter for the
HX model).
For flushing operation, a coupler hose is available
(unnecessary for the HX model) to connect to fit-
ting spigot. The other end of coupler hose is to be
connected to a garden hose to flush the whole
system by backwash. For flushing procedure, re-
fer to MAINTENANCE 02-02.
For winterization of cooling system, refer to
MAINTENANCE 02-04.
Special precautions should be taken when towing
a Sea-Doo watercraft.
When towing your watercraft pinch the water
supply hose from the impeller housing to the en-
gine with the Hose Pincher (large) Pþ/þN 529 030
400.
This will prevent the cooling system from filling
which may lead to water being injected into and
filling the exhaust system. Without the engine
running there isn’t any exhaust pressure to carry
the water out the exhaust outlet.
CAUTION : Failure to do this may result in
damage to the engine. If you must tow a
stranded watercraft and do not have a hose
pincher be sure to stay well below the maxi-
mum towing speed of 24 kmþ/þh (15 MPH).
When finished towing the craft you must remove
the hose pincher before operating it. Failure to do
so will result in damage to the engine.
The water supply is taken from a pressurized area
in the jet pump between the impeller and venturi.
The tuned pipe and exhaust manifold are de-
signed with a double wall to allow water circula-
tion.
Water is pre-heated by the exhaust system be-
fore entering the cylinder cooling jackets.
When engine is running, water must flow from
bleed outlet(s) indicating that water circulates.
Check monitoring beeper operation by jumping
terminal of thermosensor wire to ground. Beeper
must operate.
At every verification of monitoring beeper always
apply dielectric grease on thermosensor connec-
tor.
Verify wire terminal on connector for tightness. If
too loose, squeeze terminal slightly at installation.
CAUTION : When investigating for no wa-
ter flow in the cooling system, check all el-
bows and straight fittings as well as all hoses
for blockage.
When servicing the hull, always rotate watercraft
counterclockwise (seen from the rear). Rotating
watercraft clockwise could allow residual water in
tuned pipe to enter the engine and cause damage.
717 and 787 Engines Only
These engines have a Serial Cooling System ;
fresh water enters the cylinder head assembly,
cooling the combustion chamber to prevent deto-
nations. Then, water exits cylinder head toward
tuned pipe.
1. Cylinder head cover
2. Fresh water from jet pump
3. Water exiting head assembly to tuned pipe, exhaust manifold and
cylinders
A. Water from cylinder water jackets exiting engine
-
-
F01L45C
Max. 90
°
F01E1LA
2
3
1
4
www.SeaDooManuals.net