Water Leaking From Under The Bearing Housing; Loud High Pitched Rattling Whine; Excessive Vibrations, Gradually Increasing; Engine Rpm Increases Gradually Over A Period Of Time - Hamilton Jet HJ212 Installation And Service Manual

Fault Finding

Water leaking from under the bearing housing

Possible cause
Faulty water seal
Refer to section: Bearing Housing and Water Seal Assembly Dismantling on page 9-18.

Loud high pitched rattling whine

Possible cause
Blockage in the jet unit
Blocked intake screen
Faulty thrust bearing
Cavitation
Blunt or damaged impeller
Excessive impeller tip clearance
Wrong impeller type fitted
Overloaded vessel
Weight too far aft
Bad weather or sea conditions

Excessive vibrations, gradually increasing

Possible cause
Worn marine bearing
Bearing water drain hole blocked
Worn driveshaft universal joint
Refer to section: Clearing blockages on page 10-46.
Refer to section: Marine Bearing Replacement on page 9-29

Engine RPM increases gradually over a period of time

Possible cause
Worn or blunt impeller
Excessive impeller tip clearance
Refer to section: Impeller check for wear and damage: on page 8-13

Sudden increase in vibration from the jet unit

Possible cause
Debris stuck in impeller
Refer to section: Clearing blockages on page 10-46.

Gradual increase in vibration from the jet unit

Possible cause
Worn driveshaft joints
Worn marine bearing
Refer: Driveshaft, manufacturer's documentation
Refer to section: Marine Bearing Replacement on page 9-29
Solution
Inspect and replace the water seal
Solution
Remove the blockage
Inspect and repair/replace thrust bearing
Refer to section: Impeller check for wear and damage: on
page 8-13.
Solution
Inspect and repair/replace marine bearing
Clear blockage
Inspect and repair driveshaft as per manufacturers
instructions
Solution
Inspect and repair impeller
Solution
Remove debris
Solution
Inspect and repair as necessary
Inspect and repair as necessary
7-2
Installation and Service Manual