Thanks, Norm. I had a bit of trouble but I ended up using two flathead screwdrivers to pry it off. On my donor engine, which I used it's working magneto to replace, It was a bit seized so I had a mate hold the screwdrivers while I used a brass hammer to impulse it off. I finished swapping them out and got it running ok and I'm just working on the carb after school now.
Cheers Xav
