THE ENGINE LOST POWER WHILE THE AIRCRAFT WAS CRUISING AT 7500 FT MSL AT NIGHT. DURING A FORCED LANDING, THE AIRCRAFT TOUCHED DOWN ON STEEP, ROCKY SOIL. THE AIRCRAFT BOUNCED AND THEN NOSED OVER AFTER A SECOND TOUCHDOWN. DURING AN INTERVIEW ABOUT TWO HOURS AFTER THE ACCIDENT, THE PILOT REPORTED AN INDICATION OF ABOUT 1800 RPM WHEN THE ENGINE LOST POWER. DURING THAT INTERVIEW, HE INDICATED THAT HE MAY NOT HAVE USED CARBURETOR HEAT WHILE ATTEMPTING TO RESTART THE ENGINE. LATER IN A WRITTEN STATEMENT HE REPORTED THAT HE "PUSHED IN CARB HEAT" WHILE ATTEMPTING TO RESTART THE ENGINE. THE TEMPERATURE WAS 27 DEGREES FAHRENHEIT, BUT THE DEW POINT WAS NOT DETERMINED. WHEN THE FUEL SYSTEM WAS CHECKED, NO CONTAMINATION WAS FOUND. HOWEVER, DURING IMPACT, THE FIREWALL SUMP HAD RUPTURED AND THE CARBURETOR WAS BROKEN AWAY FROM THE ENGINE. AN ENGINE TEARDOWN REVEALED NO PREIMPACT MALFUNCTION OR FAILURE.