electronic ignition for B&S engine?

I have an old gardenmaster 100 rotovator (beaver powerspade) with continual spark problems. I want to convert it to electronic ignition, but can find no identifying marks on the engine.
The label on the frame says gardenmaster 100 by landmaster ltd serial number E10845.
The plate on the flywheel cover says beaver powerspade number 80112 0242-01 78020801.
I believe it is a B&S engine but there does not seem to be any marking on it anywhere, it certainly looks like a B&S and the magneto looks the same so I hope one of their conversions would work.
Can anyone identify the required conversion unit from the above info please.
Keith