Air cooled aero engines (ie most) default to over rich with the mixture forward, as it provides extra cooling from unburnt fuel during takeoff and initial climb, where cooling airflow is low.It does this by design, and is necessary. This over rich state is a great deal richer than best power mixture. So you can take off with a lean, or leaner than T/O power mixture,(if you did this and forgot the t/o checks) and the engine will run just fine, until it cracks a head or burns out a valve or any of the other nasties this may cause.The engine would need to be significantly overleaned for it to die when the throttle was opened.I always use full rich for any ground operation (unless hot'n high, which you should have training for).Leaning a bit on the ground will produce a slightly higher combustion temperature, which helps prevent crap fouling the plugs,plus there is less unburnt crap,but I think it would take a long time to overheat an engine this way.
We had a lot of problems in the 80's when the fuel grade changed to 100LL, and found plug fouling after as little as 3min of ground running quite common on some, generally older engines.If this occured, the technique was to lean for maybe 10sec at runup power, to about best power mixture,then try the mags again at full rich.Sometimes needed repeating for a little longer, or at slightly higher power. If it made no difference after the first attempt, there was something wrong with a lead or a plug.