Thanks Bruce.
I bit the bullet this afternoon and pulled the beast apart. Turns out I was half right in the start, it had blown the upper seal right up to the flywheel. See the photos
The lower seal seems to be hidden behind a metal cover which I cant see how to remove?
![[Linked Image]](https://www.outdoorking-forum.com.au/forum/uploads/usergals/2011/02/full-4644-482-dsc00963.jpg)
![[Linked Image]](https://www.outdoorking-forum.com.au/forum/uploads/usergals/2011/02/full-4644-483-dsc00965.jpg)
For the record I measured the flywheel side crankshaft seal as 32mm OD and 20mm ID.