Why Is My Outboard Not Pumping Water?

Make sure the cooling-water intakes are fully submerged or connected to the correct flushing device exactly as the manufacturer directs. Remove visible weeds or debris only with the engine off. Never run the pump dry to see whether it starts working.

The small outlet can clog even when the engine is receiving some cooling water. The reverse is also possible: a stream may be present while flow elsewhere is restricted. Temperature, alarms, water pressure where equipped, and the engine's full cooling path matter.

A technician may inspect the pump housing and impeller, verify the water tube connection, test thermostats, check pressure-control components, and look for debris in passages. Missing impeller vanes should be located rather than assumed to have exited safely.

After the cause is corrected, the engine should be tested using the procedure for that model. Verify stable temperature, alarms, telltale behavior, and water pressure where equipped rather than judging the repair from the stream alone.

If the problem followed an impeller failure, inspect for pieces in the housing and downstream cooling path. If it followed shallow or debris-filled water, examine the intake and passages for obstruction. Documenting the cause helps determine whether the normal replacement interval should be shortened.