Narrative:

On climbout we were given a climb from 5;000 ft to FL190. Autothrottles armed; we commanded a climb to assigned altitude. At about 7;000 ft MSL; we both noticed a #2 engine N1 overspeed; flashing red dial and associated left yaw. First officer (pilot flying) immediately retarded thrust levers to mid range level and maintained control of the aircraft. It appeared the number 2 engine rolled back due to the overspeed; but when the thrust levers were retarded; the #2 engine appeared to have auto relit. Both engines were now operating normally in the mid power ranges. We coordinated with dispatch and maintenance about the occurrence and elected to divert. We did not declare an emergency. Approach and landing were uneventful. I had contacted the flight attendants as we were turning to a divert airport to keep them informed. I asked them if they noticed anything unusual; and they did not feel the yawing moment; only felt the aircraft was flying a little slower than normal. Made a PA and told the passengers that everything was fine; but we were making a precautionary landing just to be safe. On a side note: the previous flight on descent; we got a master caution light and an ovhd warning for about five seconds. We never did see anything abnormal on the overhead panel. The light went out and the remainder of the approach/landing was uneventful. In hindsight; I suspect it was an eec on the verge of failing and it materialized on the next flight. Dispatch/maintenance/ATC all worked seamlessly for us.

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Original NASA ASRS Text

Title: B737-700 flight crew experienced an over speeding engine during climbout. The thrust levers are retarded and the engine returns to normal operation but the crew elects to divert to a suitable alternate.

Narrative: On climbout we were given a climb from 5;000 FT to FL190. Autothrottles armed; we commanded a climb to assigned altitude. At about 7;000 FT MSL; we both noticed a #2 engine N1 overspeed; flashing red dial and associated left yaw. First Officer (pilot flying) immediately retarded thrust levers to mid range level and maintained control of the aircraft. It appeared the number 2 engine rolled back due to the overspeed; but when the thrust levers were retarded; the #2 engine appeared to have auto relit. Both engines were now operating normally in the mid power ranges. We coordinated with Dispatch and Maintenance about the occurrence and elected to divert. We did not declare an emergency. Approach and landing were uneventful. I had contacted the flight attendants as we were turning to a divert airport to keep them informed. I asked them if they noticed anything unusual; and they did not feel the yawing moment; only felt the aircraft was flying a little slower than normal. Made a PA and told the passengers that everything was fine; but we were making a precautionary landing just to be safe. On a side note: The previous flight on descent; we got a Master Caution light and an OVHD warning for about five seconds. We never did see anything abnormal on the overhead panel. The light went out and the remainder of the approach/landing was uneventful. In hindsight; I suspect it was an EEC on the verge of failing and it materialized on the next flight. Dispatch/Maintenance/ATC all worked seamlessly for us.

Data retrieved from NASA's ASRS site as of July 2013 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.