How many engines Apollo 13?

Answer 1

The CSM (Command Module) had one main engine. The LM (Lunar Module) had a Descent engine and an Ascent engine. Both the CSM and the LM had some tiny steering rockets. These would not be considered "engines" as such as their purpose was not propulsion. That makes three engines.

Of course, the Saturn 5 boosters were also engines, but you seemed most interested in the Apollo 13 craft itself, not the boosters that sent it up. In other words, the engines it had during the emergency, not before launch.

The Lunar Module descent engine was the one that powered the Apollo 13 home, as the CSM engine could not be fired, due to the lack of electrical power the accident caused.

Answer 2

Apollo 13 had a total of five engines: one S-IC first stage F-1 engine, five J-2 engines on the S-II second stage, and one J-2 engine on the S-IVB third stage.