Having a press you could probably press both bearings into the block and then press the crank through easily.
I just do it that way as i do not have a press. But I do have lots of blocks of wood and lots of hammers.
Its probably a good idea to seperate the boss and flywheel.
A hammer on one side and a light tap on the other should see the boss come off easily. If not sit it on an anvil and tap a little harder. Not too hard up near the flywheel as that is the thinnest part of the taper. I have split a stubborn one before. Care is needed.
The washer is the trick. If you can get the crank through the bearings enough to assemble it, a washer in place of the blade disc and it all pulls together nicely.
