What was found
ENGINE HAS BEEN RUNNING ROUGH AND VERY RICH AT IDLE. IDLE MIXTURE WAS ADJUSTED DUE TO A RISE OF OVER 100 RPM WHEN CHECKING. ACFT FLEW FOR A FEW MORE HOURS, BUT MIXTURE WAS RICH AGAIN. ALSO WHEN ACFT WAS PARKED OVERNIGHT, FUEL STAIN WAS ON THE GROUND UNDERNEATH THE DRAIN TUBE FOR THE INDUCTION BETWEEN THE AIR FILTER AND FUEL SERVO. UNCOWLED ENGINE, CAPPED THE FUEL OUTLET FROM THE SERVO, TURNED THE PUMP ON AND OBSERVED FUEL SEEPING FROM THE GROOVE JUST BEHIND THE 4 SENSE TUBES INSIDE THE THROAT OF THE FUEL SERVO OR FUEL INJECTOR. REPLACED SERVO WITH AN O/H UNIT.