Probably made by Gilson. Gilson is long gone, but was absorbed by Lawn Boy. Try a Lawn Boy dealer (preferably one that's been around for a long time) in your area. The last I knew (several years ago) they were still providing support for the old Gilson stuff.

Something is the mists of my aged memory makes me think that AMF made Penneys tillers - but maybe it was Gilson. Anyway, go to this GardenWeb link and see if the pics look like your machine; if so, click on the original posters "my page" and try contacting him by email to see what he found out.

Good luck.

Here is a link that might be useful: GardenWeb archive