Mercury Jet 25 - TROUBLESHOOTING; Engine Over-Speed (Excessive RPM); Performance Loss

TROUBLESHOOTING
24
Engine Over‑Speed (Excessive RPM)
POSSIBLE CAUSES
• Outboard mounted too high on the transom.
• Worn jet pump impeller or liner.
• Incorrect jet pump impeller clearance adjustment.
• Tilting the outboard out beyond a vertical position.
• Cavitation of the impeller due to rough water or obstruction in
the boat hull.
• Blockage of the water intake.
Performance Loss
POSSIBLE CAUSES
• Throttle not fully open.
• Damaged impeller.
• Incorrect engine timing, adjustments, or setup.
• Boat overloaded or load improperly distributed.
• Excessive water in bilge.
• Boat bottom is dirty or damaged.