THE PILOT STATED THAT AS HE WAS DESCENDING AFTER CROSSING A MOUNTAIN RIDGE LINE, THE ENGINE STARTED RUNNING ROUGH AND THEN QUIT COMPLETELY. THE FAILURE OCCURRED OVER UNSUITABLE TERRAIN, HOWEVER, THE PILOT LOCATED A NARROW GRAVEL ROAD AND EXECUTED A FORCED LANDING. THE LANDING WAS MADE WITH A 13 TO 16 KNOT TAIL WIND. DURING THE LANDING ROLL THE PILOT LOST CONTROL, THE AIRPLANE VEERED LEFT, AND NOSED OVER. NO EVIDENCE OF MECHANICAL FAILURE OR MALFUNCTION WAS FOUND ON THE ENGINE. THE PILOT, IN HIS INITIAL INTERVIEW, STATED THAT HE SUSPECTED CARBURETOR ICE. A REVIEW OF THE ICING PROBABILITY CHARTS INDICATED THAT, FOR THE ATMOSPHERIC CONDITIONS THAT EXISTED, THERE WAS A THREAT OF VISIBLE CARBURETOR ICE AT BOTH RATED ENGINE POWER AND GLIDE POWER SETTINGS. TEMPERATURE AND DEW POINT WERE 77 DEGREES AND 64 DEGREES RESPECTIVELY.