I've locked this board so it is available for reference only. The active forum for the site can be found here: http://vsgt.aforumfree.com/index.htm
That is a Tecumseh engine. The manufacturer source code of 143 gives it away. If it were a Briggs, it would be 500. Here is just one internet listing of the source codes: http://www.professional-power-tool-guide.com/Craftsman-Sears-Manufacturing-Source-Code.htm