Sorry for the delay but I was looking for some info and found this thread,
You have more than likely done it by now, but the drive shaft comes off easily enough. Take the screws out of the cover in front of the engine and the drive shaft will come out with this, remove the second cover and you can remove the drive shaft coupling if needed by simply unscrewing this. The ignition unit is right in front of you.
Gerry
June 2010