THE AIRPLANE WATERLOOPED DURING THE TAKEOFF RUN AFTER NEARLY WATERLOOPING ON THE PREVIOUS LANDING. POSTACCIDENT EXAMINATION DISCLOSED THE LANDING GEAR CABLE WAS IMPROPERLY RIGGED, ALLOWING THE LEFT AFT PONTOON WHEEL TO DEPLOY. MAXIMUM RPM COULD NOT BE ATTAINED BECAUSE THE PROPELLER GOVERNOR WAS NOT PROPERLY ADJUSTED. A REVIEW OF THE ACCIDENT VIDEO TAPE REVEALED AIRCRAFT HAD ATTAINED SUFFICIENT FLYING SPEED. PILOT DID NOT DEPLOY TAKEOFF FLAPS.