Hi David,
The engine is a 147cc Atco Villiers. It is the same as those used on the early post war 17 and 20 inch cylinder mowers. Unfortunately, those engines are not the most common but parts do pop up. It really depends on what you are after, if it is only new points, condenser and coil there are a few suppliers here and in England that can usually supply these. Be careful with the flywheel cover, exhaust and fuel tank as these are not a common items (particularly the flywheel cover as it has the centre punched out) and it will not be easy to get new ones. Same goes for any aluminium castings. Generally, unless the machine is really rusted tight most of the parts will free up with a bit of penetrene or similar.
Cheers,
Sir Chook
