Hi all,
I decided to take Norm's advice and leave the boss on there and use a washer to fill in the gap. When reinstalling the engine to the body, I got heard a scraping sound and of course, figured I'd misaligned something again. Fortunately, it was just the flywheel which had been slightly lowered in the process of trying to remove the boss, which was rubbing against the engine shield. After heading up to Bunnings, $0.69 later I had an M20 galvanised washer which fit just about perfectly. 75NM torsion bar and an impact wrench and the 4 blade disc is on.
Cheers all,
pau13z
