On February 1, 2008, at 0830 Pacific standard time, a single-engine Cessna 152, N49811, experienced a loss of engine power on takeoff and landed hard following an emergency landing on runway 13 at Palo Alto Airport of Santa Clara County (PAO), Palo Alto, California. West Valley Flying Club operated the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91 as a positioning flight. The commercial pilot, the sole occupant, was not injured. The airplane sustained structural damage to the firewall and fuselage. Visual meteorological conditions prevailed for the local area flight that was originating at the time of the accident. The flight was destined for San Carlos Airport (SQL), San Carlos, California, and no flight plan had been filed. According to the pilot’s written statement, she reported that during maintenance work the previous day, a piece of baffling was found in the throat of the carburetor venturi. The carburetor was removed, cleaned, inspected, and reinstalled. The following morning, she performed a post maintenance run-up inspection and then intended to return the airplane to SQL. After start up, she performed a run-up, and all indications were normal. She taxied to runway 31 where she performed another run-up with no problems noted. On the takeoff roll, the engine developed 2,300 rpm’s, and all gages were in the "green." On climb out, she reported a 600-foot-per-minute climb at 70 knots. She lowered the nose to reduce the climb rate, but left the throttle and mixture in the full forward position. About 500 feet mean sea level (msl), the engine experienced a "hesitation." The pilot stated that she did not believe she could complete the pattern and land on runway 31, so she made a 180-degree turn back to runway 13 and informed the controller of her intent to land. With the runway in front of her, she reduced the airspeed to just above a stall and performed a "couple of S-turns and then slipped the [airplane]." The pilot stated that the airplane was still high and she was concerned about overshooting the runway. About halfway down the runway in an attempt to lose altitude, she reduced the airspeed as much as possible and the sink rate increased. She lowered the nose and attempted to slow the sink rate, and then raised the nose again to flare prior to landing; however, the sink rate was too high and she was not able to raise the nose before it struck the runway. Rossi Aircraft, Inc., Palo Alto, California, performed an engine inspection. The engine inspection revealed that the bottom number 1 cylinder spark plug was "excessively" fouled with carbon deposits. The other spark plugs exhibited normal operating signatures. Maintenance personnel performed a compression check of all the cylinders. Cylinder numbers 2, 3, and 4 showed normal compression results. The number 1 cylinder had zero compression. Maintenance personnel reported blow-by past the piston rings and exhaust valve of the number 1 cylinder. The carburetor heat box was inspected with no damage noted that would have restricted the airflow; however, the seals were missing. The carburetor was removed and inspected with no mechanical discrepancies noted; they did note about 2 ounces of water in the fuel bowl.