2001 Polaris SLH, Virage PWC Factory Service Manual, Page 164Get this manual
Final DrivePropulsion VentilationCavitation Diagnostics
If watercraft exhibits poor performance during acceleratinghigh engine RPM with little forward speed or power, incor sistent RPM, or difficulty pulling skiers out of the water, pump ventilation or cavitation may be the cause
Ventilation
Ventilation results when air enters the pump inlet tract and is compressed by the impeller, causing reduction in thrust and an increase in engine RPM Small leaks are often difficult to diagnoseA hole or crack the size of pin in the sealed area around the pump intake tract is enough to cause ventilationSome possible sources of air are: 1Intake scoopAn improperly sealed intake scoop is the most common cause of ventilationMake sure the scoop has complete bead of Marine Grade silicone sealer all the way around without any gaps or pin holes Sometimessmall leaks in the silicone sealer around the intake scoop are hard to detect with visual inspectionThe following method may make it easier to seeSee page 5.17 for scoop installation1Turn high speed fuel screws out (counterclockwise) 12 turnand operate the craft234Remove intake grate, and look for exhaust trail (black smoke path) in the area around the scoop Remove intake scoop, clean and re-seal with complete bead of Marine Grade silicone sealantRefer to illustration below for critical sealing points in the pump areaReinstall pumpride plate, and intake grate and set high speed screws back to original position