Water Discharge From Idle Exhaust During Off-Idle Operation - Mercury 300XS OptiMax User Manual

TROUBLESHOOTING
Water Discharge from Idle Exhaust during Off-Idle
Operation
Normal operation. This outboard is designed to discharge water
though the idle exhaust boot (located at the aft end of the bottom
cowl) when operating at speeds above idle. The volume of
discharged water increases with boat speed as a result of the
engine cooling system.
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