Why doesn't my Yardman snow blower spark?

I have a Yardman 31220-8 w/ a Teseh H50-6520 1J engine. I just rebuilt the carburetor and did not have this problem before the rebuild. I could get it started, but it wouldn't stay running, before the rebuild and had good spark. Now there is 0 spark and I have tried 2 different plugs. HELP!! Many thanks!