THE FLOAT EQUIPPED AIRPLANE MADE A LOW PASS OVER A LAKE. POWER WAS ADDED FOR A GO AROUND AND THE ENGINE FAILED TO RESPOND. WHILE MANEUVERING FOR THE LANDING, THE AIRPLANE CONTACTED THE LAKES SURFACE IN AN APPROXIMATE 30 DEGREES NOSE DOWN ATTITUDE WITH A 45 DEGREE LEFT BANK. WHEN INTERVIEWED AFTER THE ACCIDENT, THE PILOT SAID THE MIXTURE WAS LEAN DURING THE LOW PASS AND REMAINED LEAN DURING POWER APPLICATION. THE ENGINE WAS TEST RUN SATISFACTORILY FOLLOWING THE ACCIDENT.