CFM doesn't recomend single engine taxi out. They give several reasons:
Starting an engine without outside supervision (leaks, fire,etc); warm-up time (Airbus tells 2 minutes but CFM says optimum is 10-15 mins) that reduces engine life or could result in engine failure. So adding all up, it's not worth it.
So, I won't do single engine taxi out, however I'll do it when I taxiing in.
Check Six Krueger...
