C-FVGR, a privately owned and maintained Cessna 150GX, had been rented to a pilot for flight training. Prior to departing Langley Regional, BC (CYNJ), the pilot sumped the fuel, and then filled both tanks. About an hour into the flight while flying at 3000 feet ASL in practice area CYA185 over Stave Lake, BC, the pilot conducted a stall and the engine (Continental O-200-A X) stopped producing power. The pilot recovered the aircraft from the stall, however engine power could not be restored.
The pilot radioed a MAYDAY, which was relayed to Vancouver ACC by an overflying aircraft. Shortly afterwards, the engine began to produce intermittent power.
The pilot was able to maintain 2000 feet ASL and elected to return to CYNJ, approximately 18 nm South West. Inbound to CYNJ, the mode C function of the aircraft’s transponder stopped operating and, after the landing, the engine quit while taxiing to the apron.