Ok , last thing I know of to try ...
Could the speed of the drill be going TOOO slow ? A lot of the 2 strokers need a certain RPM before they will create spark.
Try and remove the plug , ground out the plug after removal and hit it with the drill and see if you get any spark .
Between the HP output of the engine , verses the output of the drill , you might not have enough HP and RPM from the drill .
I found this out with a BLACK AND DECKER bat operated drill . ( so , I went and used a regular AC powered drill and used a invertor that I had - extra - used to use them in the truck before I got everything DC opertated )
Worked good then .
let us know