HELP I WAS OUT YESTERDAY IN MY LITTLE BOAT EVERYTHING WAS FINE, THE WATER PUMP WORKED GREAT THEN AS I WAS RETURNING I NOTICED A DROP IN RPM AND NO WATER WAS COMING OUT THE HOLE, I STOPPED THE MOTOR AND GOT HOME,

WHAT WOULD HAVE HAPPENED AND WHAT DO I DO, I CAN FIX IT MYSELF BUT WHAT WOULD BE THE CAUSE?

PLEASE HELP