Cessna 150
Flight Crew Flight Instructor; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 240; Flight Crew Total 25000; Flight Crew Type 500
Confusion
Aircraft Equipment Problem Less Severe; Inflight Event / Encounter Other / Unknown
Aircraft Equipment Problem Dissipated; Flight Crew Diverted; Flight Crew Landed in Emergency Condition
Aircraft; Weather; Human Factors
While enroute at 5;500 MSL; the aircraft engine dropped about 200 RPM momentarily and then returned to normal. A few seconds later; the rpm started dropping and lost approximately 600 RPM and the engine started running rough. I went through emergency procedures; including fuel; mixture; throttle; carb heat and mags; but the engine rpm stayed around 1;800 RPM. I advised approach that we were having engine problems and that we would need to land at ZZZ. I [advised ATC]; because I felt this would mitigate the risk to others; should the situation deteriorate further. In the descent; the engine returned to normal operation. I figured that the power loss could possibly have been carb ice. Nevertheless; I felt the safest course of action would be to get the aircraft on the ground to investigate what had happened.On the ground at ZZZ; I was able to locate a mechanic who was able to provide assistance. He looked over the function of all of the engine controls; but found nothing wrong. Generous sampling of fuel provided no indications of contamination. At the mechanic's suggestion; I took the airplane out and did a full power run up and checked the function of carb heat; mags; etc. The aircraft performed perfectly. I assumed that the problem was carb ice. I flew a pattern close to the airport as a precaution in case anything was wrong and then flew the aircraft to altitude to see if any problem could be detected. The aircraft performed flawlessly.
C150 pilot reported diverting due to engine power fluctuations possibly caused by carburetor icing.