Originally Posted by
43Inches
Leaning on taxi out would only be advised as far as the run-up bay, once you have completed your pre take-off checks the settings should remain that way until after take-off to avoid things like out of trim or take-off with the mixture leaned. If the aircraft is significantly fouling in the taxi between the run-up bay/area and take-off then you really should get it worked on to alleviate whats causing it.
As for 25 hour checks, god are you trying to nail the final nails in GAs coffin for no reason. Our fleet of Warriors ran 100 hours between checks in ham fisted training with no engine monitoring, simple egt and very mild leaning and the engines exceded TBO except for a few rare cases where a warranty item had to be called on (non operational caused issue). Until AD-ENG-4 this all worked fine and never had any issues related to operating. The carby O-320-D3G was relatively bullet proof, as with the O-235s on 152s. If told we had to pull the plugs every 25 hours you'd get a stern look from the owner. The O-360 series much the same unless its put in a Seminole and then that's more a cam issue and not leaning related, although thrashing it at 1800 rpm just prior to shut down would not help it. I reckon half modern engine issues are to do with them being pulled apart way more often than they need, rather than only when required. Non invasive condition monitoring is the way to go, let it run until it shows signs its not happy, then play with it. Alter operating patterns and process to make it operate longer and happier between techs pulling things apart and changing things.
Must be different fuel in Oz. Certainly my experience of engines in the 152 size needed plugs pulling before 50hrs. We have been operating a PA38 it lasts 50 hrs, even with leaning, quite a bit of lead in plugs.