Bombardier SeaDoo 1998 factory shop manual, Page 164Get this manual
Section 05 COOLING SYSTEM Subsection 02 (CIRCUIT, COMPONENTS AND CARE)
This will prevent the cooling system from filling which may lead to water being injected into and filling the exhaust systemWithout 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 engineIf you must tow stranded watercraft in water and do not have hose pincher be sure to stay well below the maximum towing speed of 24 kmh (15 MPH)Snugly install the hose pincher on the water supply hose as shown in the following illustrationsF08E01A