B737-700
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 180; Flight Crew Type 3000
Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
General Evacuated
Aircraft
We had just arrived at the aircraft for the start of a three day pairing. We were briefed by the off going crew that the aircraft was in good shape with no write ups or MELS. I boarded the aircraft to start prefight duties as the FO was out doing an exterior preflight. One of the rampers informed me that the number two engine was on fire with flames coming out the back. I looked out the forward galley door and confirmed that smoke was coming out of the front and rear of the number two engine. I informed the crew and told them to initiate evacuation of the passengers we had onboard.I asked the FO to be a safety observer and assist with the evacuation as I proceeded to the flight deck to verify if there were any fire indications. There were not any fire indications on the ECP or the light in the fire handle; but I had visually confirmed the fire; so I overrode the number two fire handle and pulled and rotated it; discharging a fire bottle into the number two engine. I then notified operations of our condition and requested fire coverage at [the] gate. I then proceeded to the cabin to check on the evacuation and visually checked the engine again to see if the fire had gone out. Smoke was still coming out of the front and rear of the engine so I discharged the second fire bottle into the number two engine. Once evacuation was complete; I shut down the aircraft did a walkthrough of the cabin to ensure all passengers and crew were out and then I egressed the aircraft.
[Report narrative contained no additional information].
B737-700 flight crew reported the #2 engine caught fire during preflight of aircraft. Captain fired both bottles and the passengers were removed from the aircraft via the jet bridge.