The CFI stated that the student preflighted the ACFT. They climbed to 3,000 ft and were practicing basic instrument maneuvers when a power loss occurred. After maneuvering to clear obstructions, then S-turning to dissipate altitude, the CFI stalled the ACFT about 15 ft AGL and short of the intended field. After the accident, the CFI collected nearly a quart of water from the left fuel tank. The CFI stated that the ACFT had a history of collecting water in the (usually left) fuel tank. The ACFT was last refueled about 1 week before the accident, and had been outside exposed to several inches of rain in the interim. Despite the history of water-in-fuel problems with the ACFT, the CFI did not check the tanks for water after the heavy rain. The ACFT's type-certificate holder reported that the top of the filler neck, which is above the wing surface, should preclude fluid in the scupper from entering the filler neck. The bottom of the filler neck, however, is attached to the fuel tank top by 6 bolts and sealed with a gasket at the attachment point.