THE PLT REPORTED THAT HE CLOSED THE THROTTLE TO SIMULATE AN ENGINE FAILURE AFTER TAKEOFF FROM RWY 06, AT ABOUT 400-500 FT AGL. HE SUBSEQUENTLY MADE A 180 DEGREE TURN BACK TOWARD THE ARPT TO PRACTICE A SIMULATED FORCED LDG, AND THE ACFT SINK RATE INCREASED TO A GREATER RATE THAN 'EXPECTED'. HE THEN ADDED FULL THROTTLE, BUT THE ENGINE DID NOT RESPOND. THE ACFT IMPACTED GRASSY TERRAIN SHORT OF AND TO THE RIGHT OF THE RWY, AND SLID ABOUT 130 FEET. A POST-CRASH FIRE ENSUED. THE PLT STATED THAT HE HAD 11 TOTAL FLT HRS IN THIS MAKE AND MODEL, ALL OF WHICH WERE OBTAINED IN THIS ACFT. HE NOTED THAT THE ACFT HAD SAT UNUSED FOR THREE YEARS PRIOR TO HIS PURCHASING IT, AND THAT IT HAD RECEIVED AN ANNUAL INSPECTION A WEEK PRIOR TO THE ACCIDENT. THE ENGINE CARBURETOR WAS REPORTEDLY EQUIPPED WITH A 'LEATHER-SKIRT' TYPE ACCELERATOR PUMP.