B737 flight crew reported a near taxiway excursion after inadvertently advancing the number 2 thrust...

Attributes
ACN	1516942
Time
Date	201802
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Make Model Name	B737-800
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Flight Plan	IFR
Component
Aircraft Component	Throttle/Power Lever
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 311
Person 2
Function	Pilot Not Flying First Officer
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 200 Flight Crew Type 2000
Events
Anomaly	Deviation - Procedural Published Material / Policy Flight Deck / Cabin / Aircraft Event Other / Unknown Ground Event / Encounter Loss Of Aircraft Control

Narrative:

We were on [the] taxiway approaching runway xx at ZZZ. Tower cleared us for takeoff. I rang the flight attendants; did a throttle burst; armed the autothrottles; and asked for the before takeoff checklist. I turned on the landing lights and verbally stated 'final clear and cleared for takeoff.' as we were making the turn at the end of [the] taxiway; towards runway ZZZ; the aircraft surged. I simultaneously steered with nose wheel steering; applied brakes; and attempted to close the thrust levers. The aircraft was still powered and fighting the brakes. At this time I noticed one of the thrust levers had somehow been inadvertently advanced; [it was] #2 I believe. I was able to close the thrust lever; continue with max braking; and bring the aircraft to a stop on pavement close to the edge of the taxiway. No passengers were hurt or inured; no damage was done to the aircraft; and no runway or taxi signs or marking were damaged.

Original NASA ASRS Text

Title: B737 flight crew reported a near taxiway excursion after inadvertently advancing the number 2 thrust lever when turning onto the runway.

Narrative: We were on [the] taxiway approaching Runway XX at ZZZ. Tower cleared us for takeoff. I rang the Flight Attendants; did a throttle burst; armed the autothrottles; and asked for the Before Takeoff Checklist. I turned on the landing lights and verbally stated 'final clear and cleared for takeoff.' As we were making the turn at the end of [the] taxiway; towards Runway ZZZ; the aircraft surged. I simultaneously steered with nose wheel steering; applied brakes; and attempted to close the thrust levers. The aircraft was still powered and fighting the brakes. At this time I noticed one of the thrust levers had somehow been inadvertently advanced; [it was] #2 I believe. I was able to close the thrust lever; continue with max braking; and bring the aircraft to a stop on pavement close to the edge of the taxiway. No Passengers were hurt or inured; no damage was done to the aircraft; and no runway or taxi signs or marking were damaged.

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.