B737-800
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Less Severe
Flight Crew Returned To Gate; Flight Crew Rejected Takeoff
Aircraft
We were given clearance to line up and wait. As we powered up; the aircraft behind us advised we had flames coming from the back of the left engine. Simultaneously we got a call from the flight attendants indicating several passengers had seen the same thing. We were already on the runway and started the shutdown of the left engine. My First Officer called for the fire equipment as Tower cleared us to exit the runway. We executed the QRC engine tailpipe fire checklist followed by the QRH checklist for engine tailpipe fire. I gave the passengers a couple PAs to remain in their seats as well as talked with the flight attendants informing them that the fire trucks were looking us over.While in communication with the CFR they informed us of no further evidence of fire or damage based on their FLIR system. I made another PA to the passengers we were going to taxi back to the gate and we would be followed by the fire trucks. We received clearance from ATC to taxi to the gate and we proceeded with no further incident.At no time during this entire event did we have any abnormal or fire indication from the left engine.
Prior to this event; we experienced a 'No Starter-Cutout' on the same engine. The checklist was performed; we pulled into the gate and maintenance performed a checklist including an engine run and deferred the Starter Cutout per the MEL. On the subsequent start; (this flight) the cutout operated normally. I am not sure if this was a cause or not.
B737-800 flight crew reported they rejected their takeoff when flames were reported at the left engine tailpipe.