Narrative:

I was headed north. Enroute at 1;100 ft just below the 1;200 ft ceiling of class C airspace; my engine began to run very rough; so I diverted to ZZZ airport which is also under the same 1;200 ft ceiling. While approaching ZZZ airport; I noticed that my aircraft had climbed to approximately 1;300 ft. Under the circumstances; I decided to hang onto the extra altitude until I was sure I had the airport. After landing; it was found to be carb ice (in clear sky) that caused the problem. In the future; I will try carburetor heat first.

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Original NASA ASRS Text

Title: Stinson 108 pilot encountered rough running engine and diverted to a nearby airport. Cause determined to be carburetor icing.

Narrative: I was headed north. Enroute at 1;100 FT just below the 1;200 FT ceiling of Class C airspace; my engine began to run very rough; so I diverted to ZZZ Airport which is also under the same 1;200 FT ceiling. While approaching ZZZ Airport; I noticed that my aircraft had climbed to approximately 1;300 FT. Under the circumstances; I decided to hang onto the extra altitude until I was sure I had the airport. After landing; it was found to be carb ice (in clear sky) that caused the problem. In the future; I will try carburetor heat first.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.