An engine needs three things to run; fuel, air and sparks.
I check those things in that order so that means fuel - change tanks pump on etc. Air - Select hot or ram or filter or something appropriate and different. Sparks - are the mags on both or is there a possibility that one bad mag is dragging the engine down in which case selecting a single mag might be a good idea. This is a simplified and rapid check which will fix many engine related problems but still leave enough capacity to fly the aeroplane.
3 Point
Last edited by 3 Point; 5th Aug 2012 at 22:01.