Narrative:

I was on a pleasure flight in a cessna 150 in level cruise at 4;500 feet MSL; I began to notice a very slight loss of RPM. This loss was corrected with the application of intermittent carb heat. As my flight progressed; I needed more frequent application of carb heat and the RPM loss without carb heat became increasingly more pronounced. About 10 minutes after my initial detection of RPM change; the carb icing had become significant enough that the engine would not run without full application of carb heat. At this time I advised ATC that I was descending down to 3;000 feet hoping that the warmer air down lower could improve the situation.I saw no improvement at the lower altitude; but the engine continued to lose power; even with full carb heat applied. Within about 30 seconds after my descent; the engine slowly but steadily lost power and ultimately ceased operation. At this point; I notified ATC that I had an engine failure likely due to carb ice and [requested assistance].after establishing best glide and locating a suitable field for an off airport landing; I attempted to restart the engine. I was concurrently updating ATC of my situation. They offered vectors to [the nearest airport] but it was too far to glide. I advised them that I was continuing to attempt a restart; but was most likely going to make a forced landing in a farmer's field.at approximately 1;000 feet AGL; I successfully restarted the engine and climbed to a safe altitude. I notified ATC that I had restarted the engine and that I planned to circle the field for a few minutes. At this point; I advised them that I no longer needed emergency handling. After about 10 minutes of circling; I determined that the engine was performing without issue. I flew home uneventfully under the watchful eye of [ATC].upon landing; I called [ATC] to thank them and let them know that I had made it safely home. They advised me that there was nothing else that I needed to do at that point. That evening; I pulled the relevant weather history and determined that at the time of my engine quitting the atmospheric conditions put me in the range of 'serious carb icing at cruise power.' I grounded the plane and reviewed with my mechanic a few days later. He determined that I wasn't aggressive enough with early carb heat and given the favorable conditions and design of the cessna 150; that I reached a point where I was making carb ice faster than I was able to melt it.in the future; I plan to laminate and keep a copy of a carb ice chart in the airplane and be aware of conditions that are conducive to the formation of carb ice. I will also be more aggressive with the application of carb heat at the first detection of roughness or RPM change. And I am considering adding a carb temp gauge to monitor the internal temperature and intervene as necessary.

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Original NASA ASRS Text

Title: The pilot of a C150 reported loss of engine power due to suspected carb ice. After regaining engine power; the flight was successfully completed. The pilot noted the need for more awareness to carb ice conditions and more aggressive use of carb heat.

Narrative: I was on a pleasure flight in a Cessna 150 in level cruise at 4;500 feet MSL; I began to notice a very slight loss of RPM. This loss was corrected with the application of intermittent carb heat. As my flight progressed; I needed more frequent application of carb heat and the RPM loss without carb heat became increasingly more pronounced. About 10 minutes after my initial detection of RPM change; the carb icing had become significant enough that the engine would not run without full application of carb heat. At this time I advised ATC that I was descending down to 3;000 feet hoping that the warmer air down lower could improve the situation.I saw no improvement at the lower altitude; but the engine continued to lose power; even with full carb heat applied. Within about 30 seconds after my descent; the engine slowly but steadily lost power and ultimately ceased operation. At this point; I notified ATC that I had an engine failure likely due to carb ice and [requested assistance].After establishing best glide and locating a suitable field for an off airport landing; I attempted to restart the engine. I was concurrently updating ATC of my situation. They offered vectors to [the nearest airport] but it was too far to glide. I advised them that I was continuing to attempt a restart; but was most likely going to make a forced landing in a farmer's field.At approximately 1;000 feet AGL; I successfully restarted the engine and climbed to a safe altitude. I notified ATC that I had restarted the engine and that I planned to circle the field for a few minutes. At this point; I advised them that I no longer needed emergency handling. After about 10 minutes of circling; I determined that the engine was performing without issue. I flew home uneventfully under the watchful eye of [ATC].Upon landing; I called [ATC] to thank them and let them know that I had made it safely home. They advised me that there was nothing else that I needed to do at that point. That evening; I pulled the relevant weather history and determined that at the time of my engine quitting the atmospheric conditions put me in the range of 'serious carb icing at cruise power.' I grounded the plane and reviewed with my mechanic a few days later. He determined that I wasn't aggressive enough with early carb heat and given the favorable conditions and design of the Cessna 150; that I reached a point where I was making carb ice faster than I was able to melt it.In the future; I plan to laminate and keep a copy of a carb ice chart in the airplane and be aware of conditions that are conducive to the formation of carb ice. I will also be more aggressive with the application of carb heat at the first detection of roughness or RPM change. And I am considering adding a carb temp gauge to monitor the internal temperature and intervene as necessary.

Data retrieved from NASA's ASRS site 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.