You know it is described in detail in 'the guide' right ?
Short version >
The points should be clean first right ?
Next .. rotate the flywheel till the points gap is about .014" .. (the range is .012 to .016 - use a feeler guage) .. adjust them till they are in that range.
Then .. find the 'F' mark on the outside of the flywheel.
Line it up with the mark on the engine case.
The points should JUST crack open when the F mark and the case mark line up.
(but don't set it by changing the gap you just set .. the points sit on a plate you can also move a little)
.. move that plate till the points open when the F mark lines up.
How do you know the points just opened ?
x Either just eyeball it (crude and inaccurate)
x Or use a cigarette paper in the points .. (it should just pull out when the points crack open when the F mark lines up as you rotate the flywheel)
x use an electrical meter
x use a light bulb and battery and wires (the points become a switch)
Note .. I've never worked on a PC50 ..but I am pretty sure it has a seoarate plate that the points sit on .. to set timing.