On Memorial Day, Monday, 05/25/09 I filled up in Suffolk, Va, KSFQ, with Mogas. This gas is 87 octane. The header tank took 3.4 gallons of fuel. I took on a total of 35.4 gallons of fuel.

After the fill-up, I headed back home to Y47. Initially I climbed to 10,000 ft.

1 hour and 15 minutes into the flight over Clarksburg, WV, (KCKB) at 14,000 ft and after pumping 9 more gallons of Mogas into the header, the engine stopped producing power. The density altitude was 16,000 ft. I turned on the pitot heat, pulled the carb heat and slightly enriched the mixture. The fuel pressure read zero. I thought that something must have been frozen but the temperatures were too high. The OAT was 5°C and the carb temp was 6°C.

I declared an emergency and headed to KCKB, about 20 miles away. By 12,000 ft the engine was started up again. ATC cleared me to 10,000 and I headed back toward Detroit. The rest of the flight was just peachy.

I have gassed up in Suffolk with Mogas twice prior to this flight but never gone above 8,500 ft.

Today I sumped the plane and found water in the gasalator sump. No water in the wings. The header tank gas looked clean as did its finger strainer. There was no alcohol in the gas.

I think that the gas may have vaporized at the 16,000 density altitude. Any other ideas?

--
Lorn H. 'Feathers' Olsen, MAA, ASMEL, ASES, Comm, Inst
DynaComm, Corp., 248-345-0500, mailto:lorn@dynacomm.us
LNC2, FB90/92, O-320-D1F, 1,570 hrs, N31161, Y47, SE Michigan