Well, I got a recipe for several carby cleaners off the net. The one I used was a mixture of kerosine and paint stripper. I left the carby sitting in it for 24 hours and I didn't think it would work as it was a very lumpy mixture. Anyway I blew it out with compressed air and poked all the orifices with a stripped wire tie. I changed the fuel in the mower and put the carby back on. You would'nt believe it but it started on the 3rd pull and ran like a new mower. There are still a couple of problems though.
1. It revs too high and the throttle control doesn't seem to make much difference.
2. I have to reconnect the kill wire if the coil is OK.
3. The amount of smoke was lethal.
If anyone has a picture of the throttle linkages for a B&S 12F series mower it might help.
This isn't really a restoration, it's more loke a repair but I did feel good when the mower started.